Table of contents

Preface

Dear Ladies and Gentlemen, respectable Colleagues and Friends of KOD,

The 10th International Conference Machine and Industrial Design in Mechanical Engineering - KOD 2018 is organized by Faculty of Technical Sciences, University of Novi Sad from 6th till 8^th of June 2018.

KOD 2018 is an anniversary conference, the 10^th time, and we organize it for almost twenty years. KOD Conference has become over the years a tradition of the Faculty of Technical Sciences, carried on by the Department of Mechanization and Design Engineering.

List of Conference Chair and Committees are available in this PDF.

All papers published in this volume of IOP Conference Series: Materials Science and Engineering have been peer reviewed through processes administered by the proceedings Editors. Reviews were conducted by expert referees to the professional and scientific standards expected of a proceedings journal published by IOP Publishing.

The author's life line has been traced from the investigation of various exotic gears to design and manufacture of gear-boxes for the main drive of rolling mills.

The roller profile is of paramount importance in rolling bearing design because, under the most bearing loadings, it should provide low stresses and a long bearing life. But, unfortunately, it is impossible to find a universal optimal profile for a certain roller whatever the actual compressive load on the roller is. In the first part of this paper a complex procedure to find the optimal log-profiles of the cylindrical rollers (appropriate to specific bearing loading ranges) is presented. Since, for economic reasons, many times it is necessary to machine a simplest profile, in the second part of the paper a method to find the best 2ZB approximation (partial crowned profile) of the optimal profile of the rollers of a cylindrical roller bearing is given. The purpose is defined as an optimization problem and solved by means of Evolutionary Algorithms. To validate the optimization and considering four significant criteria, the obtained profile was compared with the optimal one and the full crowned profile used until recently.

3D processes are one of the most innovative and perspective technologies for the production of machine parts. Currently, this technology is developing very quickly and is becoming more and more competitive for traditional methods of making prototypes and models, as well as for the production of functional products - semi-finished products or finished machine parts. It is used in many areas of life - from medicine and biomechanics, through such industries as: automotive, aviation, film production, to art, jewellery, furniture production and fashion. The paper presents the characteristics of 3D techniques focused on the production of machine parts from metal materials. Selected Laser Sintering (SLS), DMLS - Direct Metal Laser Sintering, SLM - Selective Laser Melting, Laser Cusing, Laser Engineering Net Shaping (LENS), Fused Deposition Modelling (FDM) and Electron Beam Melting (EBM) have been characterized. Metal materials used in the manufacture of products using additive techniques have been presented. The advantages and disadvantages of the presented technologies were highlighted and attention was paid to economic aspects.

Product development is a creative task where is systematically created a new product, which makes possible to firms to offer attractive, innovative and market oriented products. In conditions of fierce competition and saturated markets, companies that do not innovate are stagnating and disappear from the market. Innovations are very important factor for surviving the company on the market because companies need to increase their competitive ability through development of new high quality products, introduction of new technologies in production, introduction of new organization in production, introduction of new information and communication techniques etc. Research, inventions and innovations are closely related to each other. The results of research projects can largely contribute to finding inventions and innovations and their application in creating new products and technologies. This is a very important resource that is insufficiently used in our country. The paper analyzes the role and importance of excellence and relevance of research at faculties and institutes from the aspect of their effective application in economic subjects.

Maintenance and it processes became during last decade a very important part of an organization management. It significantly helps to avoid failures, eliminate accidents, reduce machine repairs and minimize costs and corrective actions. Manufacturing organizations use different types of tool and methods to manage maintenance processes but also for their assessment. Especially now, when new standard ISO 9001:2015 with Risk-Based Thinking approach arrived, organizations are convinced to integrate "old types" of methods with "new trends" of understanding. The implementation of maintenance system is the best way how to ensure the effective maintenance activities, which are controlled but they miss systematic approach with exact requirements. The idea of systematic approach should also be added in maintenance system in the same way, as is it in Asset management. According to this ideology the Maintenance Model (PMM) was designed, which is based on the EFQM structure. The aim of the paper is present the mentioned model, which does not follow requirements of the standard ISO 9001 but helps to asses, if organization is able to meet commitments, given by management and also its ability to follow different criteria.

A chamfering of the joining sheet edges is often used in welding practice. In work, the analysis of groove weld input on residual stress distribution in single-pass butt welded joints with thorough penetration is presented. For this purpose, comparative calculations of instantaneous and residual stresses in two steel flat bars were made. The butt welded joints of S235 steel elements put to the analysis. Numerical simulations were conducted for joint with welding groove and for joint without chamfering of flats. The calculations include strains caused by temperature changes as well as the effect of phase transformations. For calculations are used authors' programs made in Borland Delphi. The results are presented in the form of temperature, volume phase fraction and stress distributions in the element's cross section as well as welding thermal cycles and stress history at selected points. The analysis of the results of the calculations showed slight differences in the stress distributions in the heat-affected zones of the considered flat bars, while it did not show significant differences in stress levels outside these areas.

Technical systems have a network structure. During mathematical model-based analysis of real technical systems, it is a key issue to determine the existence of interconnection between the subsystems and components. In cases of an integrated system the exposure of interconnections can be a difficult task because of their complexity of interconnections. Graph theory is a well-known mathematical tool; to study interconnections between components of network structure systems. The aim of this paper is to show an easy-usable algorithm for determining the existence of interconnection between the network structure system-components.

This paper presents the design of an electro-mechanical actuator that is used for actuation of a medium sized helicopter. The designed actuator consists of a commercially available electro-mechanical cylinder EMC40 from Rexroth Bosch and a brushless DC motor EC45 from maxon motor. Cylinder and the motor are connected by a custom-made gearbox, which allows for their parallel axial mount. In addition to the actuator, the paper describes a test platform that can be used to emulate the forces generated by an actual helicopter. Designed test platform consists of a torsional spring and an AC motor with excentre. Frequency regulator is used to achieve the desired frequency of the force. Experimental results obtained by testing the designed actuator on the test platform are also given in the paper.

The aim of this paper is a numerical study of the connections that are established between main elements of the steel structure of pallet racks, frames and beams. Frames that lie in the vertical plane consist of two perforated columns linked together by a system of diagonal and/or horizontal bracing welded or bolted to the columns. Beams connect adjacent frames and lie in the horizontal direction. Beam-end connectors are welded to or otherwise formed as an integral part of the beams, which has special devices which engage in holes or slots in the column. There are different types and designs of beam-end connectors which characterize the different racks manufacturers. Currently the only way to determine moment-rotation curve with structural properties of such connections is an experiment. In order to avoid a large number of expensive tests with aim to determine the main characteristics for different types of connection which in practice may be very much, this paper shows developed numerical model to simulate the experiment using the finite element method. Using the developed model can be made a global analysis of the structural behaviour and the calculation of elements according to the procedures defined in the relevant standards and recommendations.

Excavators as operating machines or equipment are exposed to diversetypes of undesired conditions, such as variable workloads, exposure to various environment conditions, unprofessional or imperfect maintenance and others. This paper demonstrates a case of anexcavator slewing ring failure which is investigated. The study suggests the failure to be caused by improper control and inadequate maintenance. The example is illustrated by photodocumentation with description of damage and probable causes in details. In conclusion, distinctive types of conditions are listed for consideration while selecting the appropriate bearing for certain type of load. Further, we outline the necessary conditions needed for maintenance and monitoring the slew ring during normal operations.

Maintenance of similar multiple equipment is challenged by the complexities brought by respective maintenance needs and intervals for each equipment. Therefore, maintenance scheduling and planning becomes expensive and time intense, affecting productivity and profitability of the plant. Organizations are embracing the need to enhance maintenance planning by evaluating equipment characteristics which potentially offer benefits from reduction in maintenance costs and downtime to avoiding of unplanned shutdowns and efficiency maximization. To address this need, this study proposes a methodology that groups equipment with similar characteristics picked from lubricant analysis using fuzzy cluster analysis. Grouped equipment tend to require similar corrective and preventive maintenance (PM) actions enhancing maintenance planning and equipment availability. To validate this framework, lubricant analysis data for seventeen medium speed engines (MSE) of a thermal power plant is utilized where the derived clusters are subsequently used to group the engines. The framework offers benefits towards reduction of maintenance cost, improved planning and overall availability of the plant and equipment.

Greater braking torque, in constrained volume and weight, is a primary challenge in magnetorheological brakes' designs. This paper deals with the feasibility of increasing the overall braking torque by multiplying the number of its active surfaces in constrained volume. Improved design of magnetorheological brake is presented. Variation in number of active surfaces and their influence to magnetic flux density intensity was considered through electromagnetic simulations. Simulations on multiple models were carried out using commercial finite element method software - COMSOL Multiphysics, AC/DC module. Materials' magnetic properties, required for simulation process, were previously obtained from manufacturer or were determined by the measurements and were applied to the simulations. Post processing was utilized to calculate the magnetic flux density distribution and intensities across the models' specific cross-sectional areas. The proposed magnetorheological brake design shows great potential for braking torque increase.

Often, maintenance managers face challenges in making maintenance decisions due to the lack of sufficient and accurate information. It's not uncommon for the current problem to be resolved, but the cause of the problem remains, which is why some types of failures often recur, reducing the equipment availability and generating additional costs. To overcome these challenges, modern maintenance principles are based on the application of the equipment condition monitoring techniques. One of these techniques is used oil analysis also known as lubricant condition monitoring, which yields an insight into the physical and chemical state of the lubricating oil, as well as the condition of the machine elements that come in contact with oil during routine operation. To illustrate the benefits of employing this technique, a case study of asphalt paving machine is presented. In the case study, four basic lubricant parameters (viscosity, water content, solid particulate content and acid number) for the hydraulic system were analysed. The results of the analysis show a sudden increase in the solid particles content, due to which certain maintenance interventions had to be taken to avoid failure of the system and unnecessary maintenance costs. Also, by oil condition monitoring, after two years, maintenance staff received information which is the base for making a decision on the appropriate replacement interval of hydraulic oil.

In this work, the authors present the necessity of photometric measurements in order to determine quality parameters when changing light sources with other types of light sources. To emphasize this we conducted a case study, measuring luminous parameters on two different streets, and we determined the technical luminous coefficients that establish the lighting system quality. We made photometric measurements on a street with sodium vapours lamps and on a street with LED lamps, determined the technical light parameters and did a comparison of the results. The outcome of the case study underline the need of conducting photometric measurements and of the lighting system redesign such that, upon changing the light sources and the technical characteristics of the lighting systems, the system still fulfils the technical standards requirements. In conclusion, for each space that is to be illuminated, an optimal solution should be found, which ensures both a reduction of the energy consumptions (reducing the system's costs) and meets the technical lighting requirements.

In Romania, as well as worldwide, lignite for the production of electrical energy is mainly extracted in quarry conditions. At the present time and for the near future at least, extracting lignite will be done with the help of continuous action excavators, especially with rotary headed excavators with radial digging, that undertake the cutting and the evacuation of the rocks from the baric step and of the lignite. On the mechanized operation lines, the excavator is the leading equipment. The growth in work efficiency of the excavator is conditioned by choosing it according to the concrete conditions of exploitation and in correlation with the other equipments on the operation lines for extracting lignite and mine waste from the coating of the lignite strata, rational intensive and extensive exploitation, adopting a modern and efficient system for doing maintenance, as well as undergoing rehabilitation and modernization processes for maintaining their technical condition at a suitable level. Estimating the duration of safe functioning of an equipment that has a certain degree of risk is a requirement of current legislation. This paper undertakes to present one of the calculus methods that is at the basis of the objective estimation of the remnant life duration of an excavator.

The paper presents a method to detect cracks with a complex shape in semi-finished casting products, which bases on the vibration response of the tested element. Firstly, we contrived relative frequency shift curves for beams subjected to L and T shaped cracks by means of the finite element method. The curves were plotted for numerous crack positions along the test specimen and used to contrived crack patterns, which consist of a set of frequency shifts for several weak-axis out-of-plain modes. The patterns are collected in a database and are used as a benchmark in the damage detection process. At the end of the paper, we demonstrate through an experiment how a visual method can be used in an automated damage detection procedure to identify a crack with a complex shape.

In this article an outlook is given of our and other recent approaches of research and representation of the mathematical models of some physical phenomena that occur in the cutting process. The focus is on the mathematical power model reliability which can be evaluated by the uncertainty parameters based on all error contributors and presented along with the model. An algorithm is proposed for the recommended steps during experimental modelling of the cutting process and uncertainty estimation. The significance of certain errors sources from the measurement software, hardware and the cutting process itself is stressed.

In rubber product design finite element analysis is widely used. The aim of this research is to choose the appropriate material models and to determine the related material parameters for finite element analysis of a rubber jounce. Rubber products can suffer from large deformation upon working conditions while behaving as a non-linearly elastic, isotropic and incompressible material. Hyperelastic material models accurately describe the observed material behaviour. Uniaxial compression test of rubber specimen has been performed to determine the stress-strain curve. Using test data and ANSYS for curve fitting process, the material constants for Mooney-Rivlin and Yeoh model have been established. Finite element analysis of the compression test has been made to validate the specified material constants. It can be stated that three term Yeoh model showed better agreement with the test data than the one term formula. Two term Mooney-Rivlin model showed good match with the measurement data, thereby it is also recommended for the future investigations of rubber jounce.

For orthopedic applications 3D metal printing delivers flexible and tailor-made solutions. The greatest advantage of the additive manufacturing is that patient-specific implants can be manufactured. Determination of compressive properties of implant structure by numerical way is a demanding engineering task and it is indispensable for design purposes. In design of load-bearing biomedical implants the elastic behavior under working circumstances has to be considered. The professional literature offers different unit cell models to represent trabecular structures. In this paper the cubic open cell structures are established using CAD application and linear-elastic finite element simulations are performed. The aim of the research is to compare the material response of the investigated geometrical models.

In this paper effects of welding on mechanical and microstructural characteristics of high-strength low-alloy steel joints is presented. Testing was done at models prepared with V-groove butt joints that are done by two different welding processes. Considered welding processes were done by MMA or MIG for root pass and MAG for other passes with related consumables. Experimentally determined basic mechanical characteristics were put in correlation to relate ones that were numerically calculated. The experimentally obtained yield strength and tensile strength showed that welding process MMA/MAG provide better mechanical properties then MIG/MAG. It is implicated that selection of welding process at high-strength low-alloy steels is multi criterion analysis. If only proper welding is obtained, applications of high-strength low-alloy steel are adequate. Those applications caused specific problems related to its specific characteristics and properties especially weldability. As welding processes can be analysed from different aspects, selection of specific welding process at high-strength low-alloy steel are more complex.

A power uprate of the nuclear power plant will affect some systems, which will be exposed to new loads, transients and operating parameters. After defining of new loads, transients and operating conditions, work to qualify a system begins with modelling of this pipe system as well as modelling of supports which are active in the system. Pipe supports in pipe model are defined depending on the supports function and also their correct stiffness. After analysis is done, reaction forces are obtained in points where pipe supports are defined in the pipe model. Reaction forces from pipestress analysis, in the points where pipe supports are defined, becomes attacking forces in pipe supports analysis. A complete calculation of support is explained as well as the way to use required standard. The calculation includes stiffness calculation, calculation of membrane stress and membrane plus bending stress. In order to qualify the support a limit load analysis is performed. Finally, it is showed that pipe support could be qualified according to the standard ASME NF-3200. This paper describes use of software Pipestress and Ansys in stress analysis of piping systems and pipe supports.

The paper includes a study on optimum batch calculation in designing the technology of execution of a welded structure within a company with mechanical profile, this being one of its main objects of activity. Because of the duration of different operations in the technological itinerary is not equal or in a multiple report, loading of machinery and workers cannot be done in a uniform manner, the production process being interrupted most often, narrow places and stocks large unfinished production, which is why we tried to determine an optimum manufacturing batch that would no longer allow these drawbacks. The solution of these problems is differentiated, considering the particularities of the manufactured product, the technological process, based on the economic analysis, aiming at the adoption of an optimal variant. The method provides the possibility to determine the influence of the size of the batch of parts on the duration of its production cycle.

The Industry 4.0 is current phenomenon in industrial enterprises, which brings a revolutionary way of production. As Industry 4.0 is applied to the entire lifecycle and value chain of products, its success depends solely on the flow of information across the system. That's the point where we get the benefits from a dynamic simulation solution which is one of the cornerstones of future businesses. The solution from Siemens Tecnomatix, the Plant Simulation module, provides an effective tool for planning and scheduling manufacturing processes. This article deals with the scheduling integration of production and simulation from the field of planning and production management at the workshop level. At the same time, it focuses on the problem of custom-made production and describes the possibilities of using simulation as a new production scheduling approach.

The article presents the results of research the process of reducing the diameter of pipe ends using the necking method, which are applied to the ends of pressure hoses. The aim of the research was to determine the possibility of reducing the diameter of the S355J2G2W steel pipe by cold necking. The research was carried out using numerical analysis, which was verified experimentally. The software Simufact.forming was used for numerical research of the pipe endnecking process. Experimental tests were carried out using specially designed and made dies and a hydraulic press. As a result of the tests, we determined the pushing force for various friction conditions and the clamping force of the die for four types of grease. The article also presents experimental results of measurements of wall thickness of the pipe being reduced (diameter before and after leaving the die). The test results showed a large influence of the type of grease on: upsetting and elongation of the pipe, flow and the quality of the material surface. The test results showed the effect of the cone angle of the standard die made on the buckling phenomena during the necking process. On the basis of the conducted research, tools for changing the diameter of pipes with theoretically unlimited length were designed.

Experimental and numerical modeling and simulations of the wind influence within the atmospheric boundary layer are essential tools in optimum building structural design. Each of these methods, however, has both advantages and disadvantages. In experimental investigations performed in wind tunnels, reliable results can be obtained, but detailed information of the wind profile parameters, such as the surface roughness length z₀ or the friction velocity u*, are difficult to determine. Numerical simulations, on other hand, easily yield any information of the wind velocity profile. However, the reliability of numerical results strongly depends on the established and adopted computational model. This paper presents the computational fluid dynamics (CFD) analysis of the atmospheric boundary layer simulated in subsonic wind tunnels using appropriate types of obstacles, based on the SST k-ω turbulence model with optimized unstructured mesh and optimum selection of relevant physical model parameters, performed in Ansys Fluent software. Results have been compared with the measurements from the Assiut University wind tunnel with maximum velocity of 4 m/s, and from subsonic wind tunnel at Belgrade University, with maximum air velocity of 45 m/s. Detailed comparisons for velocity distributions with these experimental results have shown very good conformity. Also, the three-parameter fitting methods were successfully established to define surface roughness length z₀ and the friction velocity u*. Obtained results have shown that the established numerical model is able to substitute a remarkable number of expensive wind tunnel tests hours within the operational investigations of wind influence on the building structures.

In order to provide fresh air for the operator and proper pressurization against ingress of contaminants and dust, farm tractor cab must have ventilation system that forces filtered outside air into the cab. In the hot conditions, outside air is passed through the evaporator where the heat and moisture must be removed, which can be between 40 and 70% of total heat load. Consequently, there are several contradictory demands on the tractor cab's air-conditioning system. It is necessary to obtain good air quality and comfort environment keeping the power consumption as low as possible. In the same time, the air-conditioning system should be neither too complex nor too large. In this paper, qualitative and quantitative analysis of tractor cab's air-conditioning system were carried out. The results are compared in terms of power consumption and air quality and guidelines for efficient cab air-conditioning system design are given.

Structural adhesives are increasingly used in the construction of mechanical devices. Adhesive joints replace welded, soldered and other joints. The strength of the adhesive joints obtained allows the transfer of loads. The possibility of combining different materials is a significant advantage. In order to design joints, it is necessary to know the mechanical properties of adhesives. Determining them requires the use of special methods of obtaining specimens. Analytical and numerical methods of stress estimation in adhesive joints require more material data than is provided by manufacturers. The aim of the following work is to present the method of manufacturing specimens and to compare methods for determining mechanical properties based on three example structural adhesives. The paper presents two methods for determining the mechanical properties of exemplary structural adhesives: metacryl, epoxy and polyurethane adhesive. The tests were carried out on a cast and then machined specimens. Flat specimens were used in a tensile test. In compression test, round specimens were used. The results obtained from both tests were compared with the manufacturer's data. Differences and possible reasons for them were indicated. Stress distributions in the adhesive single lap joint were estimated using the Volkersen analytical method for various determined mechanical properties.

The efficiency of agricultural activity is significantly influenced by the condition of power machines used in the agricultural production. Among others, the formation and maintenance of suitable soil-conditions play a very important role in obtaining the desired harvest yield. Many types of wear have been recognized such as abrasive, erosive, corrosion, oxidation etc. The abrasive wear in agriculture equipments is the most common problem. The tillage elements are exposed to an extraordinary high load and a significant wear, therefore it is necessary to investigate the relationship between their active layer and durability. Abrasive wear is probably the most significant cause of mechanical damage of equipment components coming in contact with abrasive bodies. The purpose of our research work is to change the old, worn cultivator tines to tines having a longer durability; hot metal powder spray fusing has been used in order to realize our aim. The products made by us will be used in the agricultural production in the future therefore the type of layer build-up technology to be used during the production can be determined. As a cultivator is equipped with a lot of cultivator tines, the expenses can significantly be decreased by the use of cultivator tines made by a well-chosen layer build-up technology and a higher yield/agricultural area can be obtained during the cultivation.

The brake pads are an important component in the braking system of vehicles. Materials used for brake pads should have high durability, stabile and reliable frictional and wear properties under varying conditions of load, velocity, temperature and environment. In this regard, has been produced an organic frictional material with coconut fibre, friction modifiers, abrasive materials and solid lubrificant using powder metallurgy. In this paper are presented the experimental determinations carried out under laboratory conditions for testing the friction material developed. In this sense will be analysed density, porosity, hardness, mechanical properties, the evolution of the friction coefficient and the temperature field in the contact area between the disc and the brake pad on an own design installation. The results performed in the laboratory give a better image about the performance of the developed friction material recipes designed to make the brake pads for small and medium vehicles.

The paper presents the results of experimental tests under static and cyclic loads of thick-layer adhesive joints. The test specimens were made of X2CrNi12 steel sheet (PN-EN 10027-1: 2007), 1.6 mm thick. BETAMATE BTR adhesive was used for gluing. Bonding was carried out under strictly controlled conditions, i.e. 20 °C and 23 % humidity. The specimens underwent aging in various conditions. Subsequently, experimental tests were carried out under static load. The obtained results allowed to determine: tension strength of glued joints S_u, yield stress S_{y 0.2}, elastic modulus E and elongation ΔL. Plots of static strength allowed to calculate the value of work W, needed to damage the joint. The second stage of the research covered of determination of the aging effect of the specimens on fatigue life. The research was carried out in the conditions of constant amplitude loads with asymmetric cycle coefficient R = 0. The obtained results allowed to assess the influence of the aging process of adhesive joints on its fatigue life.

The number of papers in the topic of autonomous vehicle research is growing exponentially. This paper addresses the problem of self driving a car on tire grip limit, in other words it gives a simple model of a race car driver. Driving is transformed into a simple deep learning problem, where the agent has one action, that is the direction in which the actual speed vector needs to be modified for the next step, and the environment state contains of the actual position and speed. The environment models the race track as a two colour map, to decide on and off track positions, and the car as a point mass with maximal possible acceleration according to the so called GG diagram. Results show that the agent can learn how to drive on the track under the described circumstances.

A new type of specimens, being the subject of the patent application in Poland, was used in the studies. The sample consists of two beams: top one (longer) made of structural material such as steel, aluminium alloy and bottom one (shorter), which is part of the glass, which is tempered, layered or traditional glass. The top beam may have any cross-section, e.g. rectangular, square, c-shaped, etc., which is characterized by different values of the moment of inertia. The bottom beam, meanwhile, is made of rectangular glass. The tests were performed under four-point bending conditions at monotonic incremental bending moment values on the Instron 5965 durability machine. The sample allows bending tests to be performed at bending loads while maintaining a constant bending moment in the glued joint area. The new type of specimen has been developed to allow for the testing of glued joints of different structural rigidity, with special emphasis on the steel-glass, aluminum-glass, steel-aluminum and similar connections. The experimental study of the durability of adhesive joints under four-point bending conditions with the monotonic incremental bending moment allows to determine the values of stresses, whose value is related to initiation of damage of the tested joint.

Polylactide is compostable and biodegradable thermoplastic polymer. It is made from renewable sources like tapioca roots, corn starch or sugar cane. Polylactide can be used as a material in food and packaging industries. According to manufacturer's instruction biodegradable bioplastics can be used for disposables applications such as cups, cosmetic packaging etc. In some cases, the type of stored substances can affected on container stability. The aim of the study was an investigation of mechanical properties of PLA depend on its degradation rate. Obtained results show degradation process of injection moulded PLA in simulated physiological fluids. Results of the study can be helpful to prediction of the behaviour of products manufactured with biodegradable polylactide.

Understanding the vehicle behaviour in the tire saturation region, close to the grip limit, is really important when the safety during vehicle motion is concerned. In case of autonomous vehicle research, usually the so called "safety-margin" is defined to describe this limit behaviour. For this, often a simulation environment is used. These environments can over-simplify suspension parameters that leads to inaccurate results, in such conditions. This paper investigates the effect of these parameters, in a given simulation software, to understand if parameter changes, eg.: roll center height, creates the expected changes in vehicle behaviour. This way it is possible to validate, if the chosen environment is "good enough" for our safety-margin research in the future.

Numerical model of controlled cooling in the production of steel hot rolled bars was developed. The numerical model and algorithm are completed to solve problems in controlled cooling of hot rolled bars in cooling beds. The controlled cooling is performed by special placement of hot rolled bars on cooling beds. By numerical model of controlled cooling is possible to predict a transient temperature field, microstructure evolution and hardness of round steel bars during their cooling in cooling beds. The numerical model of transient temperature field is based on control volume method. The hardness and microstructure distribution in steel bars has predicted by using equations of austenite decomposition kinetic. The algorithm for prediction is based the real chemical composition. Numerical model and computer program were experimentally verified by experimental work in a real industrial production of low-alloyed steel bars. The verification of developed numerical model was performed by comparison of simulated with experimentally evaluated results hardness and cooling curve.

Modular fixtures are some of the most used fixtures for orientation and fixing of the workpieces in the cutting process. It is also know that the precision of the machining process is influenced by the overall stiffness of the modular fixtures, which, in turn, depends on the stiffness of each module, connecting elements, contacts etc. This paper comprises a study of the stiffness of modular fixtures based on the multifunctional holes system. We shall determine the influence of the applied force, of the pretension force, of the friction coefficient at sliding between surfaces in contact and of the number of joints on the normal stiffness and tangential stiffness for an orientation subassembly consisting of modules in a set based on the multifunctional holes system.

Powered roller conveyor is used as a segment of transport handling system within the warehouse. A model of this conveyor was developed using Autodesk Inventor Professional 3D CAD software. Selection of main elements, drive units and accompanying mechanisms was performed. Dimensions and parameters of the most important elements of the design (rollers, frames and drive arrangement) were determined based on previous calculations, partly presented in the paper. The concept of calculations was adopted according to the procedures defined in the standards and recommendations. The goal was for adopted design to be highly configurable, simple to install and maintain. The application of standard components ensures elimination of product damage and reduction of the costs.

This paper introduces the theory of the mass-in-mass subsystems of metamaterials by a 2-Degree-Of-Freedom vibration model with linear characteristic springs and dampers, periodic excitation. The theory is described by a traditional method, by rotating vectors, using D'Alambert's principle. Formerly this method was used only for 1-Degree-Of-Freedom and now it has been developed for 2-Degree-Of-Freedom. Relationship between the phase shift and the amplitudes of the two masses' motion has been determined. Both depend on only the Lehr's damping ratio and the frequency rate. A G₂₁ = A₂/A₁ factor has been introduced and called amplitude rate. The mass-in-mass subsystem has been described by the conducted results, so the motion and the forces are more apparent.

Based on experience from the testing of the mining stacker in the copper mine in Bor, a practical procedure of frequency simulation of the enforced vibration of the structure was demonstrated. Modelling of the excitation was performed by the harmonic function of the eccentric mass of the belt conveyor drive. The paper shows how the drive frequency excitation affects the amplitude of vibration of the supporting structure. From this, the idea is presented - an algorithm for software that would allow for keeping the dynamic properties of the members of the structure within controlled range. An experiment for accelerating the structure and its FFT analysis in the frequency domain was performed. Dynamic modelling of the structure allows obtaining the objectivised concept of the measurement system for monitoring based on the given level of dynamic sensitivity of the parts of the structure.

The cavitation erosion researches conducted on vibratory devices presents a way of degradation very similar with those encountered in industrial equipment. Photos of the cavitation cloud as well as the eroded surfaces, at various exposure periods, are the basis of the present work in the description of this destruction mechanism. For the experiments, there were used two materials: gray cast iron with lamellar graphite and a high resistance bronze. The used device is that of the Timisoara Polytechnic University Cavitation Laboratory which respects integrally the prescriptions of ASTM G32-2010 Standards. For the description of the results there are used both the roughness profiles and the structure images of the eroded areas, after four different exposure times (5, 60, 120 and 165 minutes). The cavitation erosion behavior is expressed both by the mean depth erosion (MDE) and the parameters of roughness values of the affected areas. The conclusion show that the specific degradation is determined by the cavitation hydrodynamics, as well as by the repeated implosion of individual bubbles which forms the cavitation cloud attached to the exposed surface.

Adhesive joining is one of the well-established methods for joining structural materials, however it was not until the rapid development in chemistry of adhesives that it could gain wide recognition. It is impossible to imagine any branch of modern industry without adhesive joining technology, which proves indispensible in: aircraft, aerospace, automotive or building industries. The importance of adhesive joining and adhesive materials in the economy of modern world is unparalleled. Among the factors of crucial importance to the strength of adhesive joining it is the preparation of adhered surfaces through proper treatment that appears to predominate. The issue is even more important as the decision regarding the surface treatment is undertaken by a technologist, whereas the other elements of joining technology, such as temperature, time or load applied during cure, and the joint seasoning time are known and specified by manufacturers for each adhesive. Another factor relevant to the strength of adhesive joints is the effect of cyclic thermal loading. The disparity in the coefficient of thermal expansion of adhesives and adherends and in their thermal conductivity results in the adhesive joint being subjected to cyclic internal stresses. Thermal fatigue of cured adhesives may implicate ageing processes, increase polydispersity of the substrate and consequently affect its mechanical properties. This paper presents the results of comparative analysis of the shear strength of adhesive lap joints. The tests were performed on samples following different surface treatment methods, which were subsequently subjected to thermal shock in the varying range of temperatures between -40 °C and +60 °C.

The paper presents author's models and method for vehicle planetary transmission, which cover the stages of synthesis, kinematic, quasi-static and dynamic computations, dependability prediction and diagnostics of transmissions in operation process. The obtained data of the synthesis stage (block and kinematic diagrams, gear ratios of transmission mechanisms) are expanded at subsequent design stages with the ultimate goal of forming a complete information model (digital twin), allowing to support transmission design process and predict the behaviour of the transmission in operation. The emphasis is made on the developed original methods solving the most science intensive problems in the transmission life cycle.

In a paper, the important original results on various topics of gears and gear transmissions are generalized and enhanced, which are described at large in the monograph 'Gears and Transmissions in Belarus: Design, Technology, Estimation of Properties', Minsk, 2017 (in Russian). Achievements of Byelorussian scientific schools in field of mechanical gear transmissions and polymer composite gears are presented. Technological aspects, models and methods for calculation and design of drives and their components as well as estimation of lifetime, noise and vibration characteristics are described. The complex of key issues for development, manufacturing, diagnostics and testing gears, which largely determines the competitiveness of machines and their transmissions, is considered. The activities of Belarusian scientists in IFToMM are characterised, including their contribution to identification of terminology on gears. The paper is a kind of guide on science-intensive developments of Belarusian specialists in the field under discussion.

New automated systems for designing gear drives and adoption of standard computer software on gearing are considered. A review of different software solutions for designing gears, gear drives and gear forming tools is presented. Methodological aspects and numerical results of designing injection-moulded plastic gears and forming mould dies for their manufacturing are shown, including the techniques of tooth profile construction and adjusting gear accuracy parameters. The possibilities of a two-level calculation procedure for strength and wear of composite gears made of dispersion-filled plastics aimed at optimization of reinforcing filler content are noted. The results of application of known standard automated systems, such as IOSO, KIMoS and other for quality improvement of the front loader gearbox and transmissions of "Belarus" tractor are discussed.

Turboshaft engines, as the rule, contains gear transmission unit – reducer and belong to the group of drive systems with the name motor-reducer. These are the compact and autonomous assemblies for various applications. In the case of turboshaft engine in combination with high speed reducer, arise the set of phenomenon which has to be solved. Majority of them are in relation to reducer protection of overheating and of gears and bearings failures. The article contains analysis of heat sources, heat transfer through design structure and heat taking out in order to maintain acceptable temperature level of reducer lubricant. Theoretical discussions are supported with various experimental results and testing procedures, including analytic calculations. The set of design solutions for reducer protection when reducer located in the area of hot gas flow, is the main content. The case study is innovative design of turboshaft motor-reducer with free turbine which provides flexible operation and compact design structure.

In this paper, we present the finite element analysis of a cylindrical gear using the Autodesk Simulation Mechanical software, with mechanical event simulation (MES). MES combines the kinematic, rigid, and flexible-body dynamics with the nonlinear stress analysis. Therefore, MES can be used to simultaneously analyse mechanical events involving large deformations, nonlinear material properties, kinematic motion and the forces caused by this motion for predicting the resulting stresses. It is essential that MES can be used to define the surface contact between the teeth in contact at a given time, the analysis parameters by time steps, respectively the kinematic and kinetostatic parameters, variables defined by certain curves. We use the analysis to find the stress distribution, nodal displacements, etc. in the contact area of the two gear wheels, at different time steps of the kinematic cycle.

The topic of this publication is the reconstruction and measuring process of a used straight spur gear. The tooth number, the tip circle diameter and the tooth length have to be measured for the reconstruction. Based on these parameters the type of the straight spur gear has to be determined. For the designing of the gear a new computer program is created. Based on the calculated parameters the CAD model of the gear could be designed. The profile of the real spur gear is measured by a microscope having computer controlled. The real and the theoretical involute profile curve will be analysed.

Universal gear reducers are quite simple products, so today there are many manufacturers around the world that produce this kind of reducers. Their connecting dimensions and shape are not defined by the standard, so there is a large number of solutions. The most of manufacturers produce gear reducers with connecting dimensions and axis height, usually the same like the biggest manufacturers do (mainly company SEW), because they want to provide interchangeability of their gear reducers. It is interesting to note that most manufacturers are trying to adopt such a form of reducer that will be different from competing solutions in order to avoid an accusation of coping with someone else's solution, although manufacturers have almost identical shape and competing (copied) solutions. The paper presents, due to the volume of matter, only the analisys of forms of the housing of modern single-stage universal gear reducers in order to point out the expected directions of their further development.

This paper presents an analysis of the load distribution in the trochoid pump with the planetary movement of the impeller. There are a lot of theoretical and numerical analyses conducted for the gerotor of the pump with fixed positions of the gear axis. Design of planetary gerotor pump has a different load distribution than gerotor with fixed axes. A planetary gerotor consists of a fixed outer gerotor gear with internal gearing and inner gear with an external gearing. The centre axis of the inner gear has a circular motion around the central axis of the fixed gear, because of the eccentricity on drive shaft. The special shape of the gerotor teeth forms chambers with varying volume that allows the flow and pressure of the fluid. During the pump working process the forces of different direction and intensity are present in each of the working chambers. It is necessary to determine the pressure in each of the chambers in order to obtain the load model of the gerotor. Load model will enable the calculation of load distribution in the zone of the maximum contact stresses. This calculation should help in dimensioning of the pump and the achievement of better performance characteristics.

In this paper are presented the power losses and sources of their occurrence in worm gear reducer. These are the losses that occur in the coupling of worm teeth and worm gear, losses in bearings, seals and oil churning power losses in the transmission. Power losses are determined for the actual model of worm gear reducer, on the specialized testing device AT200 at the Center for testing power transmission at the Faculty of Engineering in Kragujevac, Serbia. The total losses are determined for different values of input number of revolution, output torque and by variation of types of oil, according to the pre-defined experiment plan. The aim of the paper is an experimental proof of theoretical assumptions of the influence of various factors on losses in the worm gear reducer.

Authors created basis formula and algorithm of calculation of tooth profile radiuses of curvature into line of contact parameters. Employment of this basis formula combined with famous Euler-Savary equation allows calculation reduced radius of curvature in any of points on line of contact and contact stress (by Herz) between teeth of gear and wheel without finding of that's profiles. This greatly simplifies the synthesis of optimal line of contact in cylindrical gears because allows to calculate any of quality indicators in any points on line of contact before finding contacting tooth profiles. And find on fixed plane places with good, acceptable, bad or unacceptable conditionals of tooth contacts There is a given an example of three tasks solutions with using programmes that was created with foundation on basis formula.

The article deals with the design of the deployment of components and the creation of kinematic bonds of the test bench for planetary gearbox. The source of the drive on test benches is an electric motor. In article is described creation of kinematic bonds for test bench with an open flow of mechanical power, the part of which is in addition to the electric motor also a dynamometer. It is also described a assembly procedure of kinematic bonds for test bench with an closed flow of mechanical power, in which only an electric motor is used, while this electric motor is the same for both test benches. The kinematics of test benches is modelled and calculated in programs KissSys and KissSoft. As a result, the article deals with comparing the energy balance of the individual test benches, especially by comparing the energy balance of the electric motor.

This article deals with the arrangement stiffness of the roller bearings with the line contact in the bearing units with regard to their durability. It analyses stationary and flanged standardized bearing units with the roller bearing using finite-element analysis. The article describes Hertz, Lundberg, Palmgren and Stribeck theories and published evaluation methods of the stiffness for the bearing units. It also evaluates the stiffness influence (variable cross-section characteristics) and other construction influences using suitable procedures where the standard for durability calculation is not taken into consideration. On the basis of the finite-element analysis results there has been created the mathematical model of the stiffness influence on more accurate determination of the basic durability of the roller bearings with the line contact.

The exploration of renewable energy sources and energy efficiency are becoming crucial for putting climate change under control. Thanks to large investments in development of technology for transformation of wind energy to useful form of energy, wind energy became one of the most sustainable energy source. According to the fact that horizontal wind turbines (HAWT) are more common, vertical wind turbines (VAWT) are gradually becoming more interesting because of less direction of wind sensitivity that those turbines have. Geometric parameters of rotor, such as aero foil shape, pitch angle, chord length, rotor radius, blades length, number of blades, significantly influence to the helical VAWT rotor performances. In order to be able to do influence analysis of those parameters to the helical VAWT performances, it is necessary to perform huge number of expensive experimental testing. In order to determine optimal number of needed experiments, special attention has to be put on experimental research designing. With correct design of experiment, expenses of helical VAWT rotor development are significantly increased, by using computer simulations tools that are very reliable in those experiment designs and computer simulations can replace preliminary experiment researches. In this paper, by using SolidWorks Flow Simulation tool, the research of influence of pitch angle, chord length, rotor radius and rotor height on the rotor torque, was performed. Design of Experiments and Optimization option, enables defining and performing huge number of computer simulated experiments, where chosen variables are changing their values in the plan range, defined with minimum and maximum, and all according to perform optimal study for more than one variable. Testing on rotor with three blades of NACA 0018 aero profile, with 5 m/s wind velocity, was simulated and presented in this paper.

The article deals with a description of a mathematical algorithm, programmed in the MATLAB environment of the company MathWorks. The algorithm serves a calculation of an optimal axial preload of rolling bearings. So that, the life of a bearing pair, arranged into "X" or "O" arrangement, is maximized according to a given load. Hence angular contact ball bearings and tapered rolling bearings are the subject matter of the article. Moreover, methods, that were used in the optimizing code, such as Hertz's contact of two bodies and Stribeck's load-distribution on rolling elements, are described in the article too. The finding is the dependency between total axial preload and life of a bearing pair.

The main factor that influences the lifecycle of the double harmonic transmission is the durability of the flexible toothed wheel, which is the most strongly stressed element of the transmission. The complexity of the stress distribution in the flexible toothed wheel depends on many factors, such as: the type of wave generator, the flexible wheel construction shape, the coupling mode of the flexible wheel and the transmission load. In the paper it was studied the stress distribution in the flexible wheel body, as well as the variation of the displacements of the nodes located on certain generatrix of the flexible wheel, by considering three types of mechanical generators with two deformation waves, materialized by: 2 rolls, 2 eccentric discs or cam. The numerical simulation of the flexible wheel was made in the elastic domain using a Finite Element Method with SolidWorks software.

The construction of modern industrial robots has imposed the assurance of a higher kinematic precision of orientation and positioning, which led to the apperance of better mechanical transmissions. The paper presents the construction and operating of such a new mechanical transmission, named the double harmonic transmission (DHT). Through the kinematic analysis of the double harmonic transmission, it was developed an original analytical calculation method of the transmission ratio for the cases of two constructive variants of these transmissions. The detailed study of the harmonic engagement processes in the two stages of double harmonic transmission has highlighted the relative movements of the teeth of the conjugated wheels.

In the first part of the paper we present the results of a theoretical study about of the vibrations of a rotating assembly consisting of a turbine rotor coupled by an elastic shaft to the rotor of an electric generator, to which vibrations come from the deformation of the shaft during operation and the static imbalance. It has been presented the differential equations for the movement for rotor of the generator, and of the turbine. There have been analysed some approximate solutions for the equations and we draw some conclusions about obtaining a stable functioning of the machine. In the second part of the paper there is presented an experimental study on a hydro-aggregate who had a high vibration level in all operating modes.

The paper presents technology of forming of a face gear cooperating with cylindrical worm in spiroid gear drive application for rotation table. The method is based on application of a disc tool instead application of a hob. The solution is possible after application the CNC milling machine with five axis numeric system control. The method of forming face gear proposed in this article is based on application of the disc tool with a single blade edge and CNC milling machine. The method of forming the face gear cooperation with cylindrical worm on CNC milling machine with continuous divide and the scheme of the process kinematics have been presented in the paper.

The article deals with analysing the stiffness of a special type of bearings called slewing bearings. The purpose of the analysis is to examine the stiffness of the bearing steel. This type of bearings is most often designed for operation in which the rolling elements and hence the rings themselves are loaded in the axial direction. However, the aim of the work is not only to examine the stiffness but to identify possible ways that would favourably affect the stiffness, achieving the maximum lifetime or the maximum hours of operation. Stiffness measurements will be performed in the Ansys Workbench calculation program. On the basis of the measured values, manual calculation will be performed on the basis of which possible inaccuracies that arise from the bearing production itself will be corrected.

The article deals with the influence of deformations of the individual components of the gearbox as well as their influence on the correctness of the gearing, which is essential for the correct functioning of the gearbox and its overall service life. In the next section the article deals with the effect of the gearbox deformation on the contact of the gears and the effect on the final life of the gearbox. The article it contains processing the computational model of gearbox, strength analysis gearbox, contact analysis of the selected toothed gears, taking into account the deformation of the teeth, shafts and the gearbox. The results of the work is overview size of influence individual components of gearbox on their service life.

This paper aims to develop optimal transmission architecture, constrained by selection of parameters, to be used as a reference for design of planetary gear assembly comprising of gearsets. These parameters are CAD (Computer Aided Design) geometric attributes of gear members. Planetary gearset is used in fully automatic transmission, in automotive, since this is compact, accommodates gear shifting under load and possesses high torque density, which the parallel shaft variants of gearbox do not. Fully automatic transmission involves high maintenance cost and low fuel efficiency than the manual or the automated manual types. Modelling of transmission architecture has been attempted for hybrid electric vehicle (HEV) as per the available literature, but no mathematical modelling of design parameters has been reported. This research emphasises the significance of mathematical modelling of design parameters for a planetary gear assembly and gear members for deriving optimised architecture. Mathematical models, presented in this work, are gleaned from DoE (design of experiment) based response data and are built utilising General Linear Model (GLM) for obtaining good fit. Material failure based information is expounded in this work for designing vehicle transmission architecture. Effect of design parameters on fuel consumption is also explicated in this article.

Sliding bearings' main advantages over the ball bearings are it's load capacity and longevity. If hydrodinamic lubrication conditions are met then the sliding bearings will work forever. This is especially important when dealing with high rotation rate environments, where ball bearings see very limited use due to their inferior load capacity and longevity. The focus of this study is the examination and determination of coefficient of friction values in sliding bearings made of tin based white metal alloys conditioned with hydrodinamic lubrication. A sliding bearing is based on a kinematic pair made of a steel axle and a braided alloy TEGOTENAX V840 made by Ecka Granules. The chemical composition of the this alloy is 88.7% Sn, 7.6% Sb and 3.7% Cu. The examination was performed using one oil lubricant. Experimental data has been used for creating an adaptive neuro-fuzzy inference system model. ANFIS model provides an estimation of coefficient of friction values in function of load. Based on the ANFIS model an analytical expression, used for connecting load values with coefficient of friction values, was defined. This analytical expression is suitable for engineering applications and purposes.

Regardless of the high operational reliability of modern ball and roller bearings and advanced methods for their selection and durability calculation, a significant proportion of the failures in the electric motors, about 51% [1], are of mechanical nature. Often, mechanical damage leads to irreversible engine states and costly replacement. Careful theoretical analysis of bearing failures may indicate the root causes of their defects mainly from external for the bearings surface factors and to recommend proper preventive actions. Damage cause can undoubtedly refer to the way in which significant mechanical energy generated in the rotor is transmitted, most often through belt drives or elastic couplings, while the bearings themselves withstand the significant reaction forces that have occurred. A model analysis will be performed to reveal the interconnection of the mechanical power output of an electric motor via belt drive or an elastic coupling to the internal loads and friction of supporting ball or roller bearings. In addition, a suitable lubrication regime for bearings will be examined according to different types of bearings, shaft speed and temperatures.

This paper presents design proposal for power transfer box intended for experimental light hybrid-electric vehicle. This vehicle is originally configured as parallel hybrid with mechanical power at the rear axle and two electric hub-motors at the front axle. Vehicle should subsequently be also equipped with additional electric generator enabling charging of traction batteries for front axle drive, enabling also configuration of series hybrid or range extender. Task of the transfer box described in this paper is to connect IC engine with either rear driving axle or PTO for electric generator, or both. The goal of design process is to design the transfer box by minimizing the mass and power losses.

Gears are some of the most important elements used in machinery. Their purpose is to transmit motion and torque from one shaft to another. When shafts intersect, bevel gears provide the most efficient mean of transmitting power. There are two main forms of bevel gears, straight bevel gears and spiral bevel gears. This paper is the first of a sequence of papers concerning design and manufacturing of spiral bevel gears using computer numerical control (CNC) milling machines. It is an introduction to their designing features, showing the standards that recommend the geometrical dimensions of gear tooth and a theoretical approach to the traditionally used cutting methods of spiral gears, Gleason, Oerlikon and Klingelnberg methods. Finally, it is presented five-axis machining tools that can be used for cutting of spiral bevel gears.

The tests with small plastic gears, which were conducted to assess Wöhler curves for S- and E-gears indicated improved behaviour of S-gears, which is due to their geometry. However, the thermal load of the gears in contact is of a crucial importance. Therefore, the paper focusses on the differences in thermal load of cylindrical, spur, plastic involute and S-gears. Whereas there are thermal (temperature) models at disposal for the involute gears, no models are available for the S-gears. Such a model should reflect actual flank shape and difference in actual thermal behaviour deriving from there. So, frictional power along the path of contact, work of friction and deriving flash temperatures along the path of contact were calculated for both gear types, which disclosed lower thermal load of S-gears. Small E- and S-gears made of polyacetal and nylon were manufactured by milling. So, gears were of higher quality and reflected actual tooth flank geometry. The later long-term experiments were planned with smaller loads to run up to 10 or 20 million cycles; in this context they were focused on measurements of a steady state bulk temperature which helped in assessment of actual contact circumstances and contact temperatures.

Screw and relieved surfaces with a profile of substantial and variable curvature are often used in machine parts and cutting tools. Among them, a special place is occupied by worm hobs for cutting the teeth of Wildhaber-Novikov gears with the profile of the generating worm, variable not only in radius, but also in sign of curvature. A technique for forming the tooth flanks of these hobs by a disk grinding wheel is developed, which allows the grinding and ground profiles in the axial section of the generating worm to be brought together as close as possible. The method for calculating the settings-up and profile coordinates of the grinding wheel is given for its performance in real production conditions.

IC engine crankshaft bearings are amongst the most loaded parts of the engine. Forces, acting on crankshaft bearings are changed very intensively during the engine operating cycle. Therefore, it would be very useful to have a visual representation of the bearings wear. For that purpose, a computer program has been developed to generate theoretical wear diagrams for all the crankshaft bearings of the engine. Theoretical wear diagrams provide a picture of the bearing material wear distribution resulting from the bearing load. The bearing load calculations used in the program are based on a statically indeterminate method. The description of the program, followed by some illustrations of its application, has been given in the paper.

The dynamic behavior of machines which rotate at extreme high speeds is crucial for stable and long operation. In design process some dynamics calculation must be taken into account to avoid potential operation near resonance areas. This paper considers dynamic analysis of the high speed reducer, designed together with the turbo-shaft engine. Resonances can occur when frequency of rotation and teeth mesh frequency are close to gear pair in mesh natural frequency, to the shafts natural frequencies and to the other parts natural frequencies. Problems can be avoided by translating resonant areas to higher or lower level of frequency by changing some design parameters, mass, stiffness and by variation of the stiffness of bearing supports. The paper presents the approaches to natural frequencies identification for the example of high speed reducer design. Some examples of design solutions, especially for elastic bearing supports and their experimental testing are also presented.

The article compares the tube heat exchanger with annular fins with innovative star shaped fins. For the analysis of the heat transfer and pressure drop, the computational fluid dynamics analysis with ANSYS Fluent software was applied. Through the tubes flow the hot water and heat the cold air flowing around the fins and tubes. The validation of selected turbulence models (k-ω SST and k-ε Realizable) was performed by annular fins comparing with the results in the literature. The results of the numerical analysis for star shaped fins for 2200 <Re< 12000 show an average of 15 % higher fins efficiency, 13 % higher Nu number on the air side with reduction of the exchange surfaces weight of 23.8 % compared to annular fins.

The present paper analyses two control methods for wind power systems to achieve optimum performance in terms of energy. The load control methods at wind turbines (WT) to achieve optimal operation, is based on the fact that the energy captured by the wind energy depends significantly on the mechanical angular velocity (MAV). In order to perform a function in the maximum power point (MPP) area, the load on the electric generator (EG) is changed and the power given by the wind turbine estimated. The first method, known as the small perturbation method, is widely used, becoming classic. The second original method consists in determining the optimal angular mechanical velocity ω_OPTIM, using a low power auxiliary wind turbine that operates without load, at maximum mechanical angular velocity ω_MAX. This value of MAV takes into account the wind speed evolution in time. The method bases on the particularity of the ω_OPTIM/ω_MAX report that does not depend on the time variation of wind speed values and has a constant value for a given WT.

The article presents an experimental demonstration stand that allows the study of phenomena that occur in a car air-conditioned installation. The stand is specifically designed to highlight the processes that take place in each component of the installation and how to vary the functional parameters of the plant, according to the user's requirements. There are presented 3D graphs of variation for the studied parameters.

This work presents a study regarding the influence of the heat glow dispersion upon the intake system of the internal combustion engines. The data were registered with a real time thermal imaging camera at various working regimes, in the case of cars destined to Drift competitions, equipped with internal combustion engines having cylindrical capacities between 2.0l and 6.0l. The propeller groups are placed longitudinal, classic constructive solution (the engine in the front and axle engines in the rear). The engines used are DOHC (double overhead camshaft) type supercharged, the gas flow being of cross flow type. This study wants to determine the influence of the emplacement, and of the used materials for the construction of the air filter and of the intake manifold upon the performance of the internal combustion engine. The obtained results after the tests allow to establish the optimum parameters regarding the efficiency of the heat flow transfer on the inlet path.

The subject of the article is a simulation of heat affected components of a device for deep drawing by extreme conditions in vacuum by high temperatures required for forming of crystallization containers made from thin molybdenum sheets. The simulation is focused on the distribution of heat in particular components in relation with their shape. There are presented the design of working components and the boundary conditions of transient thermal simulations with the results.

The work discusses the basics of active monitoring, creative and cognitive machinery process, technical systems, energy processing technologies, and control. The aim of this study was to describe, analyze and assess the idea and techniques of auto-monitor of the grainy biomass processing environment illustrated with an example of comminution technology. In order to achieve the purpose, a problem was identified and solved: what technical conditions of measures and ways of active auto-monitoring supported with active cognition of temporary states and changes in comminution properties are required for autonomous completion of the process with regard to the proposed states: a top product quality, high efficiency of the process, low impact of a product and the process of grain comminution for energy purposes? To resolve the problem created structure of auto-monitoring system and conducted simulation on multi disc mill. It was assumed that by applying genetic algorithms in the process of auto-monitoring it is possible to increase a particle-size quality of a product, improve process performance by 25.5% and ensure product harmlessness (elimination of dust contamination). It is desirable to use auto-monitoring (self-cognitive) systems to control comminution processes in power plants (also chemical and food plants) or to monitor biomass processing chain.

Bucket elevators is the most commonly used device for the transport of bulk, granular materials, from lower to higher levels. This role of the bucket elevators has been achieved thanks to its advantages, such as low power consumption, large capacities, high reliability and low maintenance costs. This paper is based on theoretical and practical analysis of the operation of the bucket elevators. The basic elements of the bucket elevators are presented in this paper, analyzing their advantages and disadvantages in practical application. The possibilities of electronic control of the bucket elevators operation as a basis for preventive maintenance are examined. The possibilities of modelling in modern software packages, individual elements of bucket elevators, primarily connecting elements, are presented. Considering that all the standards and recommendations from the practice, related to the use of bucket elevators, are covered by the analysis of the work and elements of the bucket elevators, this paper can serve as a guide in the selection and design of bucket elevators.

Efficient capitalization of energy resources is a top priority and is the concern of specialists in all areas of activity, taking into account the current energy policies in the world. Although the technological race to optimize renewable energy solutions has engendered many countries, however, a concern to reduce energy consumption - under climate change - must become a necessity. To this end, the article highlights the importance of recovering the lost energy and exemplifies the capitalization of this energy potential to an industrial consumer. Following the experimental research, based on the analysis of the lost energy recovery solutions, the optimal solution was established. The analysis of energy consumption before and after installation of the optimal system indicates reductions in energy consumption with positive effects both on the environment and on the costs of the economic operator.

For the production of electricity from renewable sources with photovoltaic (PV) systems, lately, technical solutions have been developed for both domestic and nondomestic customers. Regardless of the photovoltaic systems type (connected directly to the power grid, with the storage of energy produced in batteries or hybrids), the efficiency of the system is affected by both PV performance and losses during photovoltaic energy conversion or power grid delivery. In this regard, the article analyses the causes that affect the PV systems efficiency and proposes reduction methods. Also, the effects of average humidity and maximum wind speed on PV performance are discussed. The purpose of this study is to optimize photovoltaic systems by proposing solutions to minimize losses of any kind.

At the University of Szeged Faculty of Engineering we design solar collectors since 2005. For the tests of our collectors and for other researches about collectors we designed a measuring equipment which is capable for measuring the efficiency as the function of the specific solar irradiation and the temperature difference between the collector and the ambient air. The temperature different between the collector and the ambient air in our system is well-controlled with the fan coil which transfers the heat from the collectors to the ambient air. With this construction we can change the temperature of the fluid at the intake of the collectors and simulating transient effects. By the data loggers we have registered the values every 5 seconds. The calculation of the instantaneous efficiency of solar collector is conditioned. Based on the results of the measurements the MATLAB model of the analysed solar collectors is developed. During the design of a flat solar collector with this model the function of the efficiency could be pre-calculated.

The automotive industry is the decisive industry and the driving force behind the development of the Slovak economy. Slovakia has become one of the leading automobile manufacturers in Central Europe, whose progress began in the early 90's. Vehicle workshops provide wide spectrum of work on vehicles - assembly, welding, painting, repair, maintenance, cleaning, care and tuning which has to be implemented extremely carefully. In automobile production working environment demands on lighting are diverse and challenging and often use more energy on lighting than in other production plants. Insufficient daylight is frequent, and often windows are only located on one side, meaning that bright, homogeneous general illumination of workshops is a fundamental condition for precise, safe work. This paper describes the original methodology drawn up on the basis of valid legislation with point of view of the assessment of lighting systems in a vehicle workshops with regard to ensuring of a visual comfort and creation of requested working conditions for a visual activity, taking into account the energy saving and efficient of illumination.

This paper addresses the subject of process monitoring of self-organizing production chains. It proposes a strategy to assess in real time the production volume and quality by making use of a monitoring system that includes sensors and a program developed to this aim. The system is implemented in a critical node of the production chain and provides information used for unsupervised industrial processes conducting. In addition, the data is transmitted via the Ethernet or WiFi to the different departments (production planning, accounting, maintenance, quality assurance) as information or to request taking of measures if human intervention is needed. The efficiency of the proposed strategy is illustrated by an experimental case study in which the functioning of a machine in different states is simulated. The monitoring system's capability to recognize in real time changes in the machine state and its effectiveness to identify malfunctioning in the production chain is discussed.

The paper presents the results of the study regarding the olive harvesting trees systems and the concept of an olive tree robot. Important is the result, namely the harvesting speed and accuracy. Mechanical and automatic harvesting methods collect more olives than the traditional methods but may damage the olive trees. The necessity of an olive tree robot is based that the agricultural industry is very complex and need a lot of attention and qualified employments but is an activity only seasonal and are hands work. The same think is in grove-olive, where necessary many workers with experience to collect olives with their hands. In this case take a lot of time to collect the entire olive grove. Our study shows that the best system to increase the production of olives is to harvest the olives trees mechanics with robots.

One of the most complex situation in establishing the principles of modern complex lathes design is that the tool machine has to fulfill special purposes, like working with computer numerical controls and commands, adaptive cutting force control system and use in some manufacturing phases copying functions. The main issue in this case is choosing between adding an additional axis to the basic CNC machine or equipping the machine with a special subsystem purposed for the task. This paper compares the two possibilities mentioned above from the point of view of their capacity to satisfy the needs of the copying process, the complexity, and the cost of the machine, the precision achieved in the manufacturing process, and the complexity and cost of the process itself.

3D printing technology is leading to great advancements and expanding the limits in many engineering fields and education. Geometrical accuracy of the parts produced by 3D printing could be a very important characteristic for some purposes. In this paper the geometrical accuracy of parts produced by FDM (Fused Deposition Modelling) 3D printing technology is investigated. For this purpose a benchmark part is designed and size, form, orientation and location accuracy of different features on it are evaluated using coordinate measuring machine. Two different FDM desktop 3D printers are used for the benchmark part printing.

Composite shafts in compare with steel ones are characterized by lower weight, lower values of stress and deformation, extremely harmonic vibration damping and higher values of natural frequencies. The analysis of the optimal design of composite cardan shafts has shown that the load capacity of shaft is greatly influenced by type of material and the angle of orientation of the fibers. In this study the influence of the fiber orientation in layers of the composite laminar cardan shaft of truck on the angle of twist using a factorial experiment was analyzed. Analyzed shaft is composed of nine layers wherein the first layer is of aluminum, and the rest of carbon/epoxy composites with different angles of fiber orientation (-45°, 0°, 45° and 90°). By using the factorial experiment the optimal variant angles of fiber orientation is obtained and the effect of each layer on the angle of twist of drive shaft. The results obtained show that the factorial experiment could be applied on optimization of composite cardan shaft which influences on the improvement of the characteristics of the screw shaft.

It is a truism to say that vibrations can be a useful phenomenon and the reason of amage. Therefore, there is no doubt that when designing technical objects it is important to be able to evaluate its dynamic properties by appropriate modeling. One of the key properties of this type is damping. There are a number of methods to study this phenomenon, however, they require quite large resources. The main topic of this work is to propose an alternative, undemanding method to measure the damping property of any structure. The test is based on the analysis of the video recording of the vibrating element, on the basis of which the input quantities for further analytical calculations are determined. The method was presented on the example of the examination of damping properties of a photocurable resin used in stereolithography.

The main activities described in this article are carried out during the experimental phase of the research on composite materials manufacturing using textile inserts with natural origins fibres, oriented towards the manufacturing of composite materials samples. The objective of the research is to develop new fully or partially biodegradable composite materials by using new natural fibres and those recovered from various textile wastes. Thus, the research aims to obtain some composites with matrix of various types of polymeric materials and the reinforcement phase of textile materials so that the resulting products to be biodegradable. The textile inserts used as reinforcement are ecological, non–toxic and biodegradable and they contain bast fibres (flax, hemp, jute, divided or in combination), which can replace fibres of glass commonly used in polymeric composites. The purpose of the research is to obtain composite materials with high–structural, thermo–mechanical and/or tribological performances, according to ecological norms and international requirements in order to replace the existing classical materials, setting up current, innovative and high performance solutions, for applications in top areas such as automotive industry and not only.

Among the weight–efficient materials used in the transport industry are the composite materials with metal matrix (Metal Matrix Composites), the aluminium alloy matrix (Aluminium Matrix Composites) being an important category. From the manufacturing process, the low cost method and uniform distribution of reinforcement particulate in aluminium is a demanding challenge in this area. Among various manufacturing methods stir casting is generally accepted as a promising route because of low cost, little damage to reinforcement and stir cast components are not restricted by its size and shape. It also possesses advantages like simplicity, flexibility and applicability to large quantity production. At the same time, aluminium offers intelligent and practical solutions to recovering for recycling. This paper presents an overview of the relatively low cost stir casting technique, for use in the production of silicon carbide/aluminium alloy metal matrix composites, using recycled aluminium.

Currently, many aspects of the thermal regime of lamination are still not enough studied, and also, there are no efficient methods for the determination and adjustment of the rolls temperatures from the industrial rolling mills. The intensification of the lamination process directly influences the durability of the rolls, these being the most solicited organs of machines from whole ensemble of the lamination equipment's. Therefore, the increase of the duration of exploitation and remove of the damages through the accidental rupture of rolls, the attenuation of rolls thermal fatigue, the avoiding of thermal shock and their rational exploitation are actuality issues that must be continuously researched. The research on the durability in exploitation of rolling mill rolls represents an important scientific and economical issue. The study represents a detailed approach of the influence of some technological factors (chemical composition) on the durability in exploitation of Adamite type rolls and suggests solutions meant to increase the durability of the rolls in exploitation. The research uses data collected from the industrial use at the Faculty of Engineering – Hunedoara, as well as laboratory experiments carried out on a unique, complex and original installation. In this sense, the paper propose to present some results a series of researches and experiments of durability on testing lots, through the laboratory experiment, in distinct series, that represent the object of the laboratory research methodology.

The purpose of this contribution is comparison the results from FEM software analysis of construction profiles with real tests of concrete glass-carbon fiber components. We decided for experiments and simulations of carbon fiber tubes because our future project will be specially oriented for extremely terrain lightweight vehicle and there is a need of a light and safe frame with special chassis. The new vehicle project will be based on a modular universal design. Based on research in this area, we try to determine how we can trust the result of the virtual solution of parts of the composite structure. On the base of this outcomes we find out how to adjust the boundary conditions in phase of software computing to make relevant simulations, which can be even more precisely, effectively and true.

The current situation on a field of 3D print does not allow significant changes in the printer's construction. 3D printer's build area is often a limiting factor. The goal of this project is the design of a modular construction of a 3D printer. In the future, that would mean, that after purchase and after query for increasing build area, it would be necessary just to connect another unified block. All the changes could allow rapid modification of the printer's properties without increasing cost or rebuilding construction. As a result, it was able to develop a construction that is able to expand the build area at one axis. It is able to expand the build area with almost no limit in one direction.

This paper present the selected properties of coatings produced on steel using for metal forming processes such as forging, extrusion or pressing. For the preparation of surface layers the laser cladding with powder technology was applied. The power of laser beam was equal to 550 W and feed rate was 400 mm/min. The aim of presented study was to obtain the microstructure similar to sintered carbide. Microstructure, microhardness, chemical and phase composition as well as corrosion resistance tests were carried out and analysed. It was found that the presence of WC particles in Stellite-6 matrix had a positive influence on mechanical properties, but negative impact on corrosion resistance of produced surface layers in comparison with the unreinforced coating. Using XRD phase analysis, the presence of the hard interstitial phases (WC, W₂C, M₇C₃ and M₂₃C₆) in the matrix were confirmed.

This paper presents the study results focused on selected properties of sintered materials used for produce the tool for thermal drilling process (Flowdrill). The studies were carried out on a several series of commercial tools of Flat type from dimension 4.5 to 7.3 mm. Microstructure, microhardness, chemical composition as well as surface roughness parameters were investigated. These studies was carried out both before and after drilling processes. On the base of microstructure and chemical composition study, the content of carbides phases and content of porosity in material were determined. Additionally, in the case of tools which have been damaged during the process, the type of fracture was determined. On the fracture surfaces the beach marks were observed, thus confirming that it was fatigue crack. The possibility of applying the Flowdrill technology in industry were also described in this paper.

The Forth Industrial Revolution is a global phenomenon of the present day. It possesses a tremendous potential for transforming the Russian industry, which was traditionally considered quite conservative in the use of digital technologies. The aim of the study is to identify effective model of the Russian industrial sector development. Methodology of agile manufacturing is offered. The state of the Russian industry in the context of the digital economy development is reviewed. Theoretical and practical aspects of agile manufacturing are presented. The implementation of the «virtual design bureau» in the Public Joint Stock Company United Aircraft Corporation is highlighted. This is one of the successful examples of the introduction of advanced industrial production technologies in Russian engineering industry. Summarizing, agile manufacturing can become a promising model for Russia in the context of contemporary trends of the world industrial development.

The presented research is dealing with principles and technology of the laser cutting. The properties of the CO₂ laser beam, input parameters of the laser cutting, assist gasses, interaction with the cut material and the cutting process stability are described. Influence of the heat from the laser beam on degradation of the zinc surface layer, which serves as the anti-corrosive protection of the lower carbon steel, is considered in this paper. In the experimental part of this research, the two most important laser cutting parameters were experimentally changed, namely the type of the assist gas - O₂ and N₂ and the cutting speed.

In this paper modern methods of shaping polygons on universal CNC turning centers have been presented. Four different methods, depending on process kinematics, were investigated. Machining tests for different sample materials and polygons were performed. The results obtained from geometrical measurements allow to compare the accuracy of presented methods. Furthermore machining time for different methods were monitored to check their efficiency. The present paper provides comprehensive comparisons of methods used for shaping polygons on CNC turning centers. This research indicates potential fields of applications for mentioned methods and can be useful for manufacturing engineers.

Thirty years into its development, additive manufacturing has become a mainstream manufacturing process. Additive manufacturing build up parts by adding materials one layer at a time based on a computerized 3D solid model. It does not require the use of fixtures, cutting tools, coolants, and other auxiliary resources. Additive manufacturing (AM), also known as rapid prototyping (RP), is a powerful tool that offers the necessary competitiveness to worldwide companies. AM comprises the use of layer-by-layer manufacturing in order to build a part by addition of material. During this study a test piece was designed in order to compare the conventional, milling manufacturing process with additive manufacturing from the viewpoint of geometrical accuracy and the quality of surface roughness. The aim is to develop a test piece design and produce this work piece by milling technology and polyjet additive manufacturing method. The dimensional measurements of these workpieces will show the accuracy of the different technologies.

The paper analyses the effect of the nozzle arrangement on the continuous steel casting, depending on its shape and dimensions. At the same time, the work analyses the effect of cooling water pressure on the contact with the cast in order to improve the heat transfer coefficient at boiling. The present research in that, more specifically, disposed cooling water injection nozzle during the continuous casting method for arranging the nozzle for spraying cooling water to the cast surface to cool the play cast steel during the continuous casting of a continuous cooling water jetting nozzle alignment during casting It relates. An injection nozzle arrangement method during continuous casting is provided to evenly inject cooling water onto the surface of a continuous cast steel slab in a secondary cooling zone during the continuous casting.

The paper presents analysis of influence of pre-machining, consisting of removing the textured surface layer of the semi-finished product formed after plastic working, on deformation of thin-walled elements made of EN AW-2024 alloy after milling. The textured layer was removed from surface opposite to the machined surface. During tests, the influence on thin-walled elements deformation of the following machining strategies was analysed: High Speed Cutting (HSC), High Performance Cutting (HPC), and hybrid strategies HPC + HSC, HPC + CM, and HPC + CM (CM – Conventional Machining). On the basis of received results it was determined that residual stresses stored in subsurface, rolled, and unmachined surface layer have significant influence on value and character of deformations of thin-walled elements. Removing the textured surface layer formed after rolling changes character and value of the deformations of thin-walled elements. The largest difference between samples with initially removed textured layer and samples without such machining was determined for HPC + CM milling strategy. For this strategy, deformations without pre-machining were much larger than in the case of samples with removed textured surface layer.

Zirconium dioxide is a material that has been known since the 1960s. Its first application took place in devices used by NASA. Zirconium dioxide is used in the production of all-ceramic and hybrid bearings. Since the 1990s, it has been the most popular application in dentistry, where it is used for crowns, arches and all-ceramic bridges. It is characterized by biocompatibility, translucency and high mechanical strength. Zirconium dioxide is supplied in round blocks with dimensions of 180 × 30 mm, its properties are similar to gypsum. Full mechanical properties are obtained during sintering - baking in the oven at the temperature of 1400 degrees Celsius for 8 hours. During this process, a shrinkage occurs, which is approximately 20%. The article presents three materials from zirconium dioxide from different manufacturers, and the original treatment of zirconium dioxide was presented. Each of the processed materials has been divided into three groups. Each group for a given material was sintered in a different way. The 3-point bending strength tests were carried out using the proprietary holder on the Instron 8874 servo-hydraulic testing machine. The results of the tests were presented on the charts and summarized by the discussion.

The study attempts to evaluate the impact of short-term natural seasoning process on the state of post-machining deformations of thin-walled elements made of the EN AW-2024 aluminium alloy. Analyses were made of the impact of the technological history of the semi-finished product, in this case – the rolling direction of the plate (perpendicular and parallel to the feed direction) as well as high-performance machining strategies, such as High Speed Cutting (HSC) and High Performance Cutting (HPC) on the value of deformations of thin-walled samples, directly after machining and after seasoning. Application of natural seasoning at reducing deformations of thin-walled elements made of aluminium alloys may prove an alternative to the difficult intermediate heat treatment. The expected reduction of deformations is a result of reducing residual stresses in the material, in the course of the relaxation process. The dynamics of the natural relaxation is highly correlated with the properties of materials. The study includes an analysis of the effects of a short-term relaxation, accepted in industrial conditions (up to 1 month since the end of machining) for the EN AW-2024 alloy. If the proposed solution gives positive effects, it can bring measurable economic benefits in industrial applications. The study is completed with general and practical conclusions.

AISI 8740 is an alloy steel which is frequently preferred in plane and aerospace engineering. In this study, it was machined by electro-erosion and fatigue life of the surface structure is theoretically evaluated. For this purpose, AISI 8740 steel is processed with different processing parameters with EDM and the surface roughness and hardness of the produced surfaces are measured. Using these values in $\sqrt{area}$ fatigue model, the effect of surface structure on the fatigue endurance limit of the AISI 8740 steel was evaluated. It is the result of study that, surface roughness increases with increasing processing current and pulse duration and as a result fatigue strength limit decreases.

The main purpose is to produce the machine parts within the defined geometric limits for performing their functions where they are assembled. Production between the tolerance values stated in the technical drawing is very important for rapid assemblying of the shaft-hub connections working with the longevity of the moving mechanisms accurately. Because, production of machine parts at geometric tolerances is required in order to minimize the error-free assembly and undesirable conditions (heating, vibration, wear etc.). For this purpose, AA 7075 T651 aluminum alloy, which is frequently used in aviation, defense, automotive industry where desired geometric tolerance values are so important, is used as workpiece. It was machined by four different coating speeds (100, 200, 300 and 400 m/min), 0.1 mm / 0.5, 1.5 and 3 mm cut depths. The effects of cutting speed on geometric tolerances (cylindricality, circularity, linearity) after processing were investigated. It was observed that the increase of cutting speed is an effective parameter for increasing or decreasing the geometric tolerance values obtained. Increasing cutting speed was resulted in increase of tool vibration, and so increased vibration led to an increase in geometric tolerance values.

Nowadays, rapid prototyping technologies are available at very affordable prices. This is the main reason why they are being used in almost all industry sectors. 3D printers are currently being widely used for rapid prototyping and development of the new products. However, taking into account the permanent progress of rapid prototyping materials mechanical characteristics (usually different kinds of plastics), 3D printers are sometimes used even for production of the failed parts replacements – operating at the low load and rotational speed conditions. This is the main goal of this paper – to establish optimal 3D printing parameters (printing direction, layer height and percent of infill) which will allow printed gears to replace failed steel gears, for at least some time, enough for spare steel gears to be produced and delivered on site. Taking into account previously mentioned facts, the application of the 3D printed gears can potentially provide the reduction of maintenance delays in different industrial facilities (factories, workshops, etc.) which will consequently lead to significant energy and financial savings.

Nanoindentation testing is a method that consists essentially of touching the material of interest whose local mechanical properties as are hardness and elastic modulus are unknown. Nanoindentation testing is simply an indentation test in which the length scale of the penetration is measured in nanometres (10^-9 m) rather than microns (10^-6 m) or millimetres (10^-3 m), the latter being common in conventional hardness tests. Both load and depth of penetration are recorded at each load increment (ultimately providing a measure of modulus and hardness as a function of depth beneath the surface). The method is most suitable for evaluating of mechanical properties of thin surface layer or particular microstructural constituents and phases. In this sense, there were evaluated nanoindentation hardness and Young modulus of some structural constituent on saturated layer after nitriding of the 27MnCrV4 cast high strength steel during the realized experiments.

The paper presents the results of structural and mechanical testing of the alloyed aluminum alloys AA 2024 welded by the FSW process. Using the optimized tool and welding, 6 mm thick plates were connected. In this paper, the influence of rotation speed and welding speed on the macrostructure and cross section micro hardness of FSW welded joints of EN AW-2024 T351 a aluminium alloy is studied. The following welding parameters were used: the rotation speed of the tool did not change and amounted to 750 rpm, and the welding speed was 73, 116,150 mm / min. The compounds were obtained without the presence of errors and with an acceptable flat surface of the compound.

The paper presents the possibilities of 3D printing of chosen titanium alloy for manufacturing ready made parts. Results of examination of the surface topography of material manufactured using the AM 250 device by RENISHAW for laser sintering using the SLM method have been presented. 3D printing of metal parts has the potential to revolutionize the market of manufacturing and supplying parts. It makes it possible to dissipate manufacturing and to produce parts on request at lower cost and less energy consumption. The chosen parameters of the surface topography of titanium alloy under investigations directly after printing can differ depending on the distance from the base plate. Surface roughness parameters, isotropy and Abbott-Firestone curve after machining were also identified.

Walking mechanisms can move across different terrains. They are usually based on planar linkages with single degree of freedom. Basic idea is to, through observing human and animal locomotion, create a linkage that is more efficient while crossing rough terrains. Theo Jansen, one of the most popular walking mechanisms, is 8-bar mechanism with single degree of freedom. In this paper are presented analysis of the walking mechanisms, advantages of walking mechanisms in comparison with classical wheeled machines and the effect of certain parameters on its performances. The locus analysis was performed as well as the analysis of the leg when it touches the ground, which can contain solid information that can be of use.

In this paper we will implement new hardware control for 7 DOFs (Degrees of freedom) advanced robotic arm research platform (NeuroArm) equipped with various sensors. New hardware platform consists of Nano Pi platform which is used as a PC platform for standard PLC (programmable logic controller's) unit and will replace old system that consists of 7 16-bit ATmega processors. The goal of new PLC which is based on Linux operating system (Debian distribution) that is patched by Xenomai real time system for reducing control response time and better entire system control. Robotic arm is powered by 7 DC motors which are controlled by two PWM4 (Pulse Width Modulation) modules. Position data is acquired from 1kΩ resistive sensors using RI8 (Resistive module) module and from optical quadrature encoders using one DI16 (Digital Input) module. Also other modules PWM4, RI8 and DI16 communicate with PikoAtlas CPU module by I2C bus.

Considering the amount of time school children spend in school, primarily sitting, classroom furniture has a crucial role in the maintenance of good sitting posture and should be designed to promote it. However, there are numerous studies that have reported unsuitability of school furniture and its mismatch with students' needs and anthropometric characteristics. This paper presents the results of research conducted among 100 students from a secondary technical school who were asked to answer to the questionnaire related to the comfort of furniture they use in the classroom for computer aided design, sitting posture they take as well as how it affects their psychophysical state and learning activities. Also, T-test analysis was conducted in order to determine whether there was statistically significant difference in opinion on the comfort of the furniture between first and fourth grade students. The results indicate that students do not feel totally comfortable when sitting at a computer in the classroom for computer aided design but that the discomfort does not have huge consequences on their mental and physical state (tiredness, pain, concentration and attention) during class.

E-learning appear to be the new standard of modern education. Learning Management Systems (LMS) enable teachers to provide students with different approach of knowledge and to enhance interaction between teachers and students in simple and low time consumption way. This study was designed to identify students opinions about three courses in fluid mechanics. Each of the courses has a different cognitive complexity. They were lectured as a standard ex katedra and on-line courses. The results of this study shows learners satisfaction and preferences about different type of teaching. A discussion about increase of the students results on final exams are presented in this paper.

This paper analyzes the needs of the processing industry sector in Montenegro for the establishment of the Industrial Design Laboratory. The analysis was created as a result of the research done for the purpose of preparing the Preliminary feasibility study for the establishment of the "Industrial Design Laboratory", which would operate as a part of the d.o.o. Innovation-entrepreneurship center "Tehnopolis" in Niksic. The study was conducted on the basis of the Public Invitation of the Ministry of Science of Montenegro. The aim of the analysis is to get conclusions about processing industry needs in Montenegro, by using systematization of the parameters, its characteristics and conditions, especially in the field of product development and to identify further activities in order to correctly project directions of development of the Laboratory for industrial design. For the research, the "Delphi method" was used, as a special and recognized way to obtain relevant indicators in the world where it is not possible to reach the precise data, but the solution of the problem should be sought on the basis of estimates.

Opportunity and need of introduction to a scientific turn of new category - "tax stability", causing ability of the enterprise to answer for the tax obligations, despite the economic compensations of external and internal environments influencing him is proved in work, supporting at the same time the planned functioning mode. The research of essence of the entered category has allowed to establish her interdependence with financial stability; to allocate structure and the endogenous factors causing change of a condition of tax stability, predetermining her "compression" and "expansion"; to prove presence at the studied category of such characteristics as – locality and globality; to prove need of allocation of her temporary characteristics – quick, tactical, strategic; to predetermine that this category needs quantitative representation. Quantitative assessment of tax stability is offered to be presented to the following indicators – coefficient of a covering of tax payments; in structural coefficient of tax debt and the paid tax payments; growth rate of tax debt. Quantitative assessment of tax stability on the basis of the developed system of indicators has to is made in the planned and actual mode with the subsequent leveling of the arising deviations. It is supposed that implementation of such work should be made on the basis of the developed model of management of tax stability.

The paper deals with the role position and quality of internal audit in selected Czech organizations. Describes option for access to internal audit, the role and status of internal audit in an organization. In the next section, she addresses the Three Line of Defence model with the requirements of a high-quality internal auditing team, analyses the level of communication and reporting by both the internal auditor and the audited system. In conclusion, the paper provides an overview of the staffing capacity of internal audits. The method of collecting information is secondary research. The papers are use in the field of internal audits in selected organizations, internal technical standards, expert studies and reports published on the Internet. The aim of the paper is to get acquainted with the current state and level of internal audit.

The paper presents synthetically the main methodologies for production systems optimization. There are presented: Six Sigma, Theory of Constraints, Toyota Production System, Lean Manufacturing, Agile Manufacturing and Smart manufacturing. The comparative study analyzes the goal, the main focus, the observed problems, the methodology, the desired outcome, the primary, but also the secondary effects and some critics for each methodology. Based on such an analysis, managers can choose the optimization methodology that best suits the organization's strategic goals, technological level, and organizational culture.

The paper presents the structural design of the plastic cup stacking machine working mechanism. Based on the set requirements, a new working mechanism consisting of a cam/gear mechanism is proposed. The cam mechanism enables the change of the kinematic parameters of the working elements, and the gear mechanism provides the change of rotation direction of the output links. Based on the geometrical parameters of the cam mechanism, two principal solution of the working mechanism have been considered. Kinematic position analysis was performed and regulation characteristics have been formed. Increasing the motion range of the output shaft is approximately equal for both solutions, and the change is close to linear. However, one solution has smaller overall dimensions and more favourable values of pressure angle which makes it more efficient. The proposed solution is reliable, efficient and it has a high positioning accuracy that provides high accuracy and repeatability of movement of the output links without a time delay. The driving motor maintains a nominal number of revolution for different kinematic parameters of the machine working elements, which is a significant advantage.

It is known that a special chapter in product design is dedicated to the materials from which these products are going to be manufactured. Plastics (thermoplastic polymers, thermo-reactive polymers and elastomers) along with classical materials or composite materials are the basis for designing and making products. They are found in all sectors of industrial activity. Products are required to meet certain minimum resistance conditions for the requirements they will be subjected to, throughout their use, low manufacturing costs, etc.[1]. The better the material properties of a product are known, the better the design and manufacture of products respond to market requirements. The paper highlights the most important properties and areas of use of the currently most used thermoplastic polymers in designing and manufacturing of industrial products (polyvinyl chloride, polyethylene, polypropylene, polystyrene, methyl polymethacrylate, polyamides, polycarbonates, cellulose acetate, polyoxymethylenes and thermoplastic polyurethanes).

The development of the Arctic shelf and the Far North is hampered by severe natural and climatic conditions, remoteness from the places of permanent human habitation, lack of infrastructure and vehicles adapted to such conditions. Taking into account the need to create new models and types of transport-technological machines, the unification of the structure is rational. The article briefly presents the essence of the concept of creating a mobile complex of transport-technological machines for the Arctic with a unified platform. To create this complex, the need for key types of transportation and technological works in the Arctic was analysed. The design of machines from the complex was carried out taking into account the functional designations, ergonomic requirements and technological features of structural materials. For the development machine construction were used the methods of computer modelling and finite element analysis. The article describes an experimental sample of a technological machine created using the unified platform. The presented results of experimental studies confirm the validity of the selected solutions, the feasibility of creating a complex of machines on a unified platform and the validity of the concept as a whole.

Virtual prototyping technology is a powerful tool when exact design solution is needed, corresponding to various and sometimes controversial requirements. It is used widely for design improvement/optimisation (topology, shape, parametric), based on engineering analysis through numerical techniques (as Finite Element Method) that enables prompt and accurate solutions. Design development approach based on this technology becomes standard for many industries, including railway transport. Presented study is based on an industrial project for design development of elastic rail clip. It is entirely based on virtual prototyping to obtain adequate design solution. Design is required to achieve certain clip rigidity, at certain level of safety (mechanical stress), for certain design space. This is a typical task for design optimisation techniques and performed simulations include 3 design concepts, 11 design variants and more than 2400 parametric configurations to obtain 4 allowable design solutions. The study is a good presentation of virtual prototyping application for industrial purposes.

Article is devoted to the subject which isn't losing interest – the organization of continuous introduction of innovations. She contains statement of scientific and methodical approach to creation of this type of the organization with involvement of "bank of the ideas" and accounting of temporary aspect of introduction of innovations. Orientation to accounting of temporary aspect does necessary a research of structure and structure of time expenditure on realization of an innovation. At the same time will have to methods of the direct account and correlation modeling are involved. As a result of performance of such complex of works the scientifically based base for planning of introduction of innovations and management of these processes will appear.

The procedure of designing the columns of the flexibile facade lift is presented in this paper. Choice the optimal variant of the lattice column was realized using the AHP method. The ranking procedure was conducted for 4 criteria and 5 alternatives. The optimal alternative includes circular hollow section (CHS) and square hollow section (SHS). The column design was carried out for 6 combinations of loads according to ASCE 7-05. The calculation of the strength and stability of the column was carried out using the EN 1993-3 and the structural analysis software (SAP 2000). A column with greater lateral rigidity has a very adverse effect on local stability. A greater number of connecting points increases global, and reduces local stability of the column. Properly designed columns must have a certain degree of elasticity. The loss of stability in the case of overloading must only be manifested by global buckling due to significantly higher deformation energy. The presented analysis examines the interaction of global and local buckling. Conclusions in the form of stability criteria can be implemented in the design process.

This article gives a detailed description of the development of an experimental sensor beam support with an integrated load cell, in this paper also named a smart support. The smart support is designed as a part of a beam bending experimental apparatus. For small universities, the financial effort needed to equip experimental mechanics labs is considered unjustified for the purpose of undergraduate mechanics classes. Thus the majority of experiments conducted in mechanics and similar classes are done during lectures as 5-minute presentations using available, inexpensive and simple apparatus. Such apparatus was produced in faculty workshops, by students as a part of undergraduate theses or projects with sponsoring companies. This article describes a process of building experiment apparatus through the student undergraduate theses and cooperation with local companies. It also shows the current state of beam bending apparatus at University North and the process of creating the initial design of a smart support. Some properties of two typical versions of load cells containing strain gauges were investigated using numerical simulations. According to load cell shapes, two different design solutions of smart support were proposed. The final chapter describes future plans to create data acquisition and ideas for developing further experimental modules or devices for various other experiments.

In this paper, we present evaluations of power and motion variants on the example of a motorcycle. The choice of the optimal variant is enabled by setting goals, forming a morphological matrix and evaluating particular variants. The selected characteristic elements and their combinations will give us the most appropriate solution. For the evaluation, some basic features of the motorcycle were selected with an emphasis on the hubless wheel for the further constructional and numerical models. At the end of the paper, the constructional assemblies of the hubless wheel with emphasis on design are given.

In this paper, research of optimization parameters of continuous flow heart pump is presented. The application of centrifugal pumps as heart assist devices imposes design limitations on the geometry of the heart pump. Geometry and pump parameters affect the performance and the hemocompatibility of the heart pump. The main quality assessment factor for heart pump is the pump hemocompatibility i.e., the amount of mechanical damage caused by a pump on blood cells. Besides stagnation zones and recirculation zones, wall shear stress is parameter that is used to predict pump hemocompatibility. Second important factor is minimal volume of heart pump with acceptable anatomical fitting. Additional factors are high efficiency and durability. The aim of the research is to propose the optimal design of bladeless centrifugal heart pump. The dimensionless optimization parameters of the heart pump design are derived from Navier - Stokes equation. In conclusion, dimensionless optimization parameters of bladeless centrifugal continuous flow heart pump are presented.

The paper illustrates the reverse engineering process of a blade, from a Kaplan runner with a diameter of 5400 mm, using the following software packages: Agisoft Photoscan and Geomagic Design X (formerly Rapidform XOR); the next step was to generate the solid geometry of the blade using the SolidWorks software. The last step was to compare, using GOM Inspect software, the geometry of the designed blade with the corresponding geometry obtained using Photogrammetry and finally answer the question if this technique can be used in the mechanical field to get a precise 3D reconstruction of large objects with complex geometries.

For a blade runner of a Kaplan turbine, with its 3D geometry obtained through the Photogrammetry technique, the paper aims to determine the following geometric parameters of the blade profile: the stagger angle, the chord length, the relative thickness (maximum thickness / chord length) and relative thickness position, the relative maximum camber and the maximum position of the profile camber, using the following software packages: SolidWorks and Visual Basic for Applications included in Microsoft Excel. The blade profiles are generated through multiple sections of the axial blade runner with coaxial cylinders with the runner axis and plane unfolding. These parameters will be compared with the corresponding design parameters in order to investigate the precision of the Photogrammetry technique.

Autonomous driving, is considered as the future of mobility, and research on this topics growing exponentially. On the one hand, these vehicles must be controllable, making rapid maneuvers possible, in case of a sudden accident situation, while on the other hand their motion must be stable, to maintain directional stability under disturbances. It is important to specify the so called "safety margin", the range of possible motions that the vehicle can produce with keeping its stability. The limits of the possible movement of a vehicle depend on its parameters. The aim of our study is to determine which parameters affect the controllability and stability of a vehicle. To find this, we used the "MRA moment method" to create the "Yaw Moment Diagram" in our simulation environment. This method is usually used to map the possible range of motion and judge the stability and controllability of a possible motion state. Here we will use a two track vehicle model, with nonlinear tire characteristics, and complete model of suspension linkage to create the MMM diagram of a vehicle with given parameters.

This article describes a method to identify partial sources of noise and their respective effects on the overall noise level of a clothes dryer. The focus is on the major sources of noise and options to control their noise levels so that the resulting declaration program produces as effective as possible acoustic improvement, while maintaining the desired drying performance, as indicated by the manufacturer in the rating plate. A rating plate is the main informative indicator allowing a consumer to compare performances of various competitor products.

The presented article is an original contribution which implies the design of a specialized modular device used at the different surgical procedures applied at the human knee. The increasing of the precision and quality of the surgical procedures using specialized devices is an important goal both for the engineers and for the doctors. In the paper are presented some diseases which affect the human knee and also the possibilities of surgical treatment of those. The main knee pathology which was researched, regards the axial deviations of the human lower member and correction using HIGH TIBIAL OSTEOTOMY (HTO) in all possibilities: with opening wedge or closing wedge, medial or lateral, uniplanar or biplanar. The complexity of these surgical procedures from geometrical point of view opens up the possibility to increase the quality of the medical act through using specialized devices. In this regard, in the present article it is approached the design and the modelling of the modular device destined for the knee surgery using HTO techniques. The main objectives are: establishing the needs and requirements that the device should accomplish, the identification of the primary functions, the development of the implementation solutions, the synthesis of these solutions and finally the 3D design of the device using Catia V5R20.

The paper presents a constructive solution to the original construction of a small mobile press for the extraction of essential oils of plant origin. The press is hand-operated, intended for field treatment of plants harvested in mountainous areas. The construction of the press is made according to the special requirements of the client who plans the mass production of the press, so the price limit is a priority. The research was done using the principles of methodical design according to the standard VDI 2221.

Modern IC enignes are used on different technical field. Over the past years, there is a more and more electric cars. Electric motors can deliver their full power over a wide RPM range, actually these motors have better power characteristics. Internal combustion engines have several disadvantages, but besides this fact these engines are dominant as propuilsion systems. One of the main disadvantages is in close relation with engines power. Modern IC engines his own power release at high engine speed. In this article was presented one new engine with relativly constant engine power at wide range of engine speed.