Table of contents

Preface

This volume of "IOP Conference Series: Material Science and Engineering" contains the papers presented in the "World Symposium on Mechanical-Materials Engineering & Science" in Prague (Czech Republic) during 9-11 September 2021. The aim of the WMMES 2021 to provide a forum for discussion of the latest findings and technologies in different fields of Mechanical Engineering, Materials Engineering and other related disciplines, to give opportunities for future collaborations, to be a platform for sharing knowledge and experiences in the fields of Mechanical Engineering, Materials Engineering and other related disciplines, and to lead in providing a forum for early career researchers for presentation of their work and discussion of their ideas with experts in different fields of Mechanical Engineering and Materials Engineering.

However, the planned period of the 1^st WMMES was 2020, it was postponed to 9-11 September 2021 because of the Covid-19 pandemic, and held in Prague (Czech Republic) by appearing in person of the participants, not on-line format.

All the missions of World Symposium on Mechanical-Materials Engineering & Science – WMMES 2021 were completed, and 35 peer reviewed articles were published. We would like to thank all reviewers for their great effort to achieve the high quality of published articles.

We would like to show our deep gratitude to the honored Scientific Committee given to be list below and Institutional Scientific Partners of WMMES. The Scientific Committee and Institutional Scientific Partners of WMMES was completed by paying strict attention, and all members were selected from well-known, very much appreciated, productive and representatives of the different countries.

List of Committee Members 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 Editors. Reviews were conducted by expert referees to the professional and scientific standards expected of a proceedings journal published by IOP Publishing.

• Type of peer review: Double-blind. All articles (62) had not been sent to the reviewers when they were submitted, and the review process had been completed in 2 rounds. In the 1^st round, the articles were evaluated by means of their originality and suitability. These selected 57 articles were taken under consideration and sent to the reviewers.

Each of the selected 57 articles was first sent to at least 2 reviewers, and their comments were then sent back to the author for the requested revisions. After the completion of the revisions, the revised paper was sent back to the reviewers for the last check. By considering the reviewers' comments, decision was done.

• Conference submission management system: On-line submission system of WMESS was used for the submission of the articles. However, the review process was managed by sending the articles to the reviewers by e-mail accounts of the editorial office (editor@wmmes.org). The chairmen (Prof.Dr. Isik Yilmaz – isik.yilmaz@gmail.com, Prof.Dr. Marian Marschalko –

marian.marschalko@gmail.com, Prof.Dr. Marian Drusa – md525d@gmai.com) were responsible for the review process.

• Number of submissions received: 62

• Number of submissions sent for review: 57

• Number of submissions accepted: 41

• Acceptance Rate (Number of Submissions Accepted / Number of Submissions Received X 100): 66%

• Average number of reviews per paper: 2

• Total number of reviewers involved: 46

• Any additional info on review process: No

• Contact person for queries: Isik Yilmaz. isik.yilmaz@gmail.com

Additive manufacturing (AM) covers variety of applications in industrial manufacturing, healthcare industry, as well as 3D home printing desktop applications. It has significant contribution in the manufacturing technology development, while simultaneously creates an impact on the economy of scale. The production cost of AM is almost linear, regardless of the size of the production batch. Furthermore, an increasing parts complexity does not necessarily means an increase of the production costs. It offers new degrees of freedom in the product design, enables reengineering and redesign, and facilitates resource optimization (energy and materials) and waste reduction. At the same time, it promotes reducing the number of assembly operations while contributing to more energy efficient and more cost-effective production. As one of the mostly spread AM technologies, which is quite limited in terms of material selection but has numerous advantages, e.g. during crisis that imply supply chain disruptions, the focus of this paper is on the 3D printing features. In particular, with the assistance of Multi Attribute Analysis, this study elaborates and identifies relevant attributes describing the 3D printing process and its features through the perspective of materials susceptible to 3D printing. The holistic approach presented in this paper introduces a new perspective for decision makers in the field of 3D printing, because in addition to the traditional material selection process, introducing attributes relating only to cost and manufacturability, it includes attributes describing the extended sustainability paradigm. The approach presented herein, categorizes attributes describing the 3D printing process in five main groups, i.e. economic, social and environmental (corresponding to the sustainability paradigm), amended by the technical and legal aspects.

Presented paper is focused on 2D numerical simulation of turboprop engine cooling in the section of a gas turbine. The paper describes the issue of heat transfer by natural cooling of a turboprop engine in the turbine region in order to determine the time-dependent temperature field in the engine. The analysis is represented on a simplified double annular geometry, where the inner tube represents the engine rotor, the middle tube represents the flow path and the outer ring replaces the engine case. Simultaneous heat transfer by natural convection (Boussinesq model) and radiation (model S2S) is solved on this geometry. Numerical data were compared with data that was gained from measuring on an experimental stand. The surface temperatures of the tubes were measured on the experiment stand during the cooling of the engine model. The temperatures on the walls of the flow path were based on real temperatures of the running engine as initial conditions together with the temperature of the outer tube. The results will be further applied to the study of temperature-dependent deformation of aircraft engine parts, which have a significant effect on the safety and trouble-free operation of the aircraft engine.

Failure Mode and Effect Analysis (FMEA) is a frequently applied risk assessment methodology in different fields of industry. It provides the opportunity for deep analysis of risky events, connecting to their potential causes and effects. Due to its robust method, risk can be identified and managed but, because of its complexity, the assessment can be time-consuming, and the answers can be inconsistent. In the authors' experience, the scale used to quantify the priority number can influence these outcomes. To identify and measure the significance level of this connection, a survey was organized with experts of digital manufacturing, who were asked to rank the probability of risk occurrence in planning a production process based on digital manufacturing principles. Participants had to use three assessment methods: 1) traditional 'linguistic' scale; 2) 'ratio scale; 3) pairwise comparison. In the case of the linguistic scale, probabilities were defined by their descriptions and an integer between number 1 and 7. These numbers did not equal the probability percentage. In contrast, the ranks of the ratio scale equalled the ranges of probability percentage. In the pairwise comparison, risks were compared by the frequencies of their occurrences. The assessment results were compared by time-need, difficulty, priority list, and consistency. Time and difficulty were ranked by the survey participants on a 4-level scale. The priority list was created by the summarized rank values. In the consistency assessment, we looked at how the amended scale affects the assessment uncertainty. In addition, pairwise comparisons were used to examine the consistency of each expert's evaluation and filter out those that were not accurate enough.

In the preformed work were studied the characteristics of Ni, Mo and Cu – free austempered ductile iron microalloyed by Boron under different contact load. For microalloying liquid cast iron with boron, the ferroboron by synthesized SHS - innovation technology was used. The upper and lower bainitic austempered ductile irons were studied with different content of metastable retained austenite. The experimental samples were tested with a fixed linear sliding speed of 2 m / s at a different contact load values, which were changed in the range of 25, 50 and 100 Newtons. It was defined that the value of the contact load has a significant effect on the tribotechnical characteristics of bainitic cast irons in conditions of dry sliding friction. Particularry, they determine the structural changes character and the degree of surface layers degradation of friction. High strength cast irons with the lower bainite structure are more resistant to adhesive wear. According to the obtained data, the presence of up to 80% metastable retained austenite in the metal matrix structure of the of experimental cast irons makes it possible to stabilize the friction coefficient under the investigated contact loads. Thus, to ensure maximum wear resistance, the isothermal quenching of high-strength cast irons must be carried out in the temperature range 220-280 ⁰C with a minimum treatment time.

Due to development of different material systems and structural elements, there is growing need for more complex material models, since linear elasticity or even more complicated linear viscoelasticity cannot capture the nuances of behaviour of these materials. This study describes the process and difficulties of development of 3D nonlinear viscoelastic model. Study proposes two models with different level of complexity and methodology for experimental parameter identification. The limitations of both of these models have been discussed.

Worm gears are gear units with a shaft angle of mostly 90°. They are used in a variety of industrial applications due to large gear ratios and high transmittable torques. The high sliding ratio in the tooth contact requires a hard/soft material combination that is insensitive to scuffing. Worm shafts usually are made of case-hardened steel and worm wheels of a copper-tin-bronze alloy. Since damage predominantly occurs at the wheel (pitting, wear, tooth fracture, etc.), a wide range of calculation methods for load capacity and service life were developed. Regarding the worm shaft, only the deflection is examined, because high displacements of the shaft shifts the contact pattern, which leads to transmission errors and may lead to increased wear. Common calculation methods, e.g. according to DIN 3996 and ISO/TS 14521 provide a good approximation of the deflection. However, simplifications are made in favour of the manageability of the calculation method. Geometric modifications on the worm such as reduced tooth thickness or different lead angles cannot be taken into account with common methods. In order to close this gap, a new approach was presented by Norgauer in 2021, however, significantly overestimating the stiffening effect of the gearing in some cases by neglecting the helical winding of the worm teeth. For efficiency-optimal design of minimally thin worm shafts, approaches that go beyond the deflection are also missing. Investigations by the authors on worm gears using the finite element method (FEM) show a deviation of the bending line of worm shafts from the common calculation methods. The FEM calculations simulate the tooth meshing under load by a driving torque on the shaft, whereas the standard calculations simplify the load distribution on the worm shaft as a radial force introduced at a point. In addition to the magnitude of the radial forces, the axial tooth force component was identified as an influence factor on the bending line since it causes a displacement of the maximum bending location. Especially for increasing diameter factors the displacement of the bearings under load must be taken into account since they may be in the same range as the deflection. Furthermore, the helical winding of the teeth around the shaft leads to an average stiffening effect of the gearing. The cross-section depends on the gear meshing position and causes a periodic fluctuation of the area moment of inertia and a wobbling motion of the shaft. The changing load distribution on several teeth causes a periodic change of the lever arms and an additional dependence of the deflection from the mesh position. An analytical calculation method for the deflection of worm shafts is proposed. It aims at the precise calculation of the spatial expression of the bending line, extends the commonly used simplified model and takes the newly identified factors into account. The bending lines in both radial directions are considered separately. The values of the new introduced factors are derived from the FEM results. Finally, the calculated bending lines are compared with the FEM results and verified.

With flexible multibody simulation, the dynamical behaviour of vehicle components as well as entire systems can be simulated in an efficient way. In addition to structural vibrations, noise emissions play an important role in terms of comfort in the vehicle industry. While the dynamics of the structures can be simulated directly in the time-domain, the sound radiation is usually calculated in the frequency-domain. This process enables an efficient investigation of steady-state operating conditions but not of transient operating conditions. The time-domain Boundary Element Method (TD-BEM) in acoustics allows to determine the sound pressure directly in the time-domain, without complicated transformation from the frequency-domain. Existing work concentrates on stability criteria and general theoretical applicability. The validation on real test cases with measurement results, however, has rarely been focused. On this work, we aim to close this gap between theory and practical applications with the help of real housing structures and test cases. In order to set up an acoustic validation, meaningful measurements need to be combined with validated structural simulations that match the physical world with regard to the sound radiation as closely as possible. Therefore, several test set-ups are used to measure the real dynamic and acoustic behaviour in an anechoic chamber with multiple accelerometers, a laser vibrometer, various microphones and a sound intensity PU probe. Based on these measurements, multibody and BE-models are created, representing the same scenarios with numerical methods. Derived from the simulated surface accelerations, the acoustic radiation is calculated in the time-domain. Comparisons at a simple oval-shaped housing show that the method generates very promising results. The mean deviation between the measured and simulated sound pressure levels (time-domain) is less than 1 dB and the frequency spectra show a high quantitative correlation as well.

The effect of temperature on an end-cell plate in a proton exchange membrane (PEM) fuel cell stack is presented in this paper. Numerical analysis and experimental work investigated the impact of a heat exchanger filled with metal foam on the end-cell plate used for cooling a PEM stack. One side of the edge plate was subjected to constant heat flux (1.55 W/cm2) while the other side was insulated. A metal foam with a pore density of 40 and having a porosity of 60% was analysed. The model was simulated in ANSYS R3-CFD, and the thermal problem was solved using the local thermal non-equilibrium (LTNE) to investigate the heat transfer between the fluid and solid phases. The thermal solution studied the effect of metal foam heat exchangers at different airflow velocities between 0.2 and 1.5 m/s on end-cell plate's temperature. The results showed heat transfer enhancement in plate temperature, proving that the use of the LTNE assumption illustrated the difference between the end-cell plate and fluid flow temperatures. The effect of inlet air velocity on the plate temperature was also examined. An experimental model of a commercial PEM stack was constructed out of aluminium. This model was tested at the same conditions as those employed in the numerical solution. The heat generated by a fuel cell was simulated by a surface heater providing the same heat flux as the actual PEM cell. The numerical and experimental results for the end-cell plate for both at flow direction and different inlet velocities were assessed. There was a good agreement between the numerical and experimental results.

Simulations are one of the most used tools in different investigations and topics, being a powerful tool to replicate a real-life system or to solve real engineering problems without interrupting any process. To accomplish a reliable replication of the real system, it is necessary to make good assumptions in the numerical parameters selection of the simulation and its configuration. The main goal of this research is to propose a calibration methodology of numerical parameters based on static tests simulations in the Rocky-DEM software. A laboratory flow test experiment was developed to measure the repose (a_r) and emptying (a_e) angles of a granular material in a static state. In the simulation experiment, these angles are dependent of numerical parameters, such as the static friction coefficient (m_f), the rolling coefficient (m_r) and the adhesive distance (d_a). To get the best numerical parameters that explained the behavior in the laboratory experiment, an optimization procedure was done. Two materials were used for this research: chickpeas, for the development of the calibration methodology, and sulfide copper ore, to apply this methodology. The numerical parameters for the chickpeas experiment were m_f = 0.183, m_r = 0.105 and d_a = 0.938 [mm], resulting in a_r = 31.23° and a_e = 28.85°. These simulated angles have a variation of 2.85% and 3.03% with respect to the values obtained in the laboratory experiment. In the case of the mineral experimentation, a m_f = 0.892 and m_r = 0.269 were obtained, simulating a a_r = 30.1° and a_e = 42.31°. Also, these results have a variation of 2.84% and 3.65% with respect to the values of the angles measured in the laboratory model. As a conclusion of the study, DEM simulation is a powerful tool to predict the behavior of granular materials. However, it is necessary to use calibrated values and settings in the simulations to increase the accuracy of the results.

The aim of this research is the development of a lightweight large excavator. This is due to the need to reduce the system suitable for its movement and to increase the hourly production of the excavator. This lightweight is done on all the main components by adopting aluminum alloy and composite materials. The study, developed in analytically and in numerically way, considers different loading conditions to which the excavator can be subjected during its use. The new solution was developed in order to have almost the same performance for safety coefficient, displacement and so the stiffness and critical buckling load. The excavator in its minimum weight configuration, obtained by applying composite materials for arms and hydraulic cylinders while aluminum alloy for frame, has an operating weight that goes from the value of 577.6 kN to the value of 425.8 kN with a reduction of over 26%. With this result, three important factors are to be underlined: increase in capacity which depends on the geometric configuration of the arms (about +41.5%); a significant reduction in ground pressure allowing the use of the excavator in previously inaccessible places and finally greater ease in transporting the machine.

This study deals with thorough investigation of stress-strain parameters within an innovatively processed tungsten heavy alloy (THA). THAs are challenging materials featuring exceptional mechanical and physical properties and they are applicable in various demanding industrial fields, such as in the aeronautics, medicine, or military. The herein studied material is a WNiCo alloy prepared from original powders via powder metallurgy. The pre-sintered material was processed via plastic deformation, in particular hot rotary swaging with the usage of induction heating directly before a swaging pass. The experimental study was supplemented with numerical simulation of the deformation process, which was performed via the finite element method (FEM). The simulation was primarily focused on prediction of the development of effective imposed strain during the swaging process performed in multiple steps, and its correlation with stress distribution during swaging. The numerically predicted effective imposed strain development was subsequently verified via Vickers microhardness measurements, whereas the predicted results of stress distribution were validated via experimental observation of residual stress distribution performed via analysing scans acquired by scanning electron microscopy (SEM, electron backscatter diffraction analysis). The results showed that the deformation technology consisting of induction heating and hot rotary swaging was well optimized as the swaged billets featured satisfactory surface roughness and no surface cracks. Also, the tungsten agglomerates within the structure exhibited deformation in the direction of the main acting swaging force, especially in the locations the effective imposed strain in which was the highest. The values of predicted effective imposed strain and microhardness correlated reliably with the experimentally acquired and predicted results of residual stress distribution. In other words, the locations the effective strain in which was the highest also exhibited a more significant presence of residual stress.

In the last decade, several authors and scientists are interested more and more to understand the phenomena which are take place at aluminum matrix and silicon-carbide interface. This type of composite material is especially used in aerospace and automotive industries which involve high temperature applications. Aluminum metal matrix composites containing 5,15,25 weight % SiC_p were processed by powder mettalurgy route. The interaction between metallic matrix (aluminum) and particulate ceramic reinforcement (silicon-carbide) was studied. At the beginning the solid-state reaction behavior of the Al/SiC powder mixture compacts was investigated. The density, porosity, compressibility of Al-SiCp composites were calculated. Maximum densification of the composite material reinforced with 5% SiC is obtained at a compactation pressure of 420 MPa (94.5%). For 15% SiC content densification increase with higher compactation pressure given the density values of 95.66% and 96.46% for the 25% SiC composite. Conventional scanning electron microscopy revealed a faceted interface between SiC particulate and Al matrix. This chemical reaction at the interface is the result of dissolution of silicon carbide particulates in aluminum matrix during the liquid sintering process at high temperature:1100,1300,1450 and 1750°C in different sintering atmospheres. For intermetallic compounds identification was used an energy dispersive X-ray spectroscopy (EDX) investigation. The presence of compounds and phases such as: Al₄C₃, Al₄O₄C, Al₄SiC₄, SiO₂, Al₂O₃, confirmed by X-ray diffraction analysis is given by different sintering temperature. It is important to know the structure and chemical composition of the interface and near to the interface zone for study the mechanical properties of the reinforced metal matrix composites.

The main objective of this study is to investigate the possibility of replacing the traditional construction aggregate, river sand, with corundum material and to evaluate the effect of the proportion of corundum sand on the strength properties of fly ash based geopolymer mortar. Electrocorundum (white) and fly ash from a thermal power plant in Skawina were used to make the samples. Different fractions of electrocorundum were used to prepare the geopolymer mass. A geopolymer based on fly ash and river sand was used as reference material. The results showed that the average compressive strength of fly ash and alumina-based materials increased (results ranging from 25.9 to 47.0 MPa) compared to the reference samples (20.7 MPa). The flexural strength results showed a weakening of the strength properties of the electrocorundum and fly ash-based samples (results ranging from 6.1 to 4.8 MPa) compared to the reference sample (7.0 MPa). Only the geopolymer, which in its composition contained a mixture of electrocorundum with several grain gradations, showed an increase in flexural strength (7.3 MPa), compared to the reference sample. Additionally, surface topography analysis of the geopolymer samples was performed by scanning electron microscopy. The whole tests carried out on the above types of material indicate that it can be used as a substitute for sand in geopolymer mortars.

The paper presents the forward kinematic analysis for a new hyper redundant robot with applications in vertical farming inspections and harvesting tasks. The high dexterity and the ability to adapt to various unstructured environments makes this type of robot a good solution for this kind of applications. The robot consists of seven 3-RPS (Revolute-Prismatic-Spherical) parallel modules resulting in a 21 DOF structure. The forward kinematic analysis of one module is presented first and then for the entire structure in detail. The obtained equations are then implemented in MATLAB and validated using a virtual robot model.

Snow is a heterogenous, hot material which is constituted from ice particles. The bonding behavior of ice particles is an important parameter determining the macroscopic behavior of snow. Discrete Element Method (DEM) is usually used as a tool to model dry snow. The most important input data required into the DEM is bonding behavior of ice particles since ice particles can adhere to form bonds when they brought into contact. This study had two aims: first, an analytical formulation was derived to predict the bond diameter of ice-ice contacts as a function of time, compressive load, and strain rate. Using the previously published data for strain rate of ice, a solution method was developed. The results of bond diameter development with time were compared to experimental data and a good agreement was found. Second, a DEM for dry snow was developed and programmed in MATLAB and the developed bond model was employed in the simulation to study the deposition behavior of snow in a container under gravity acceleration. A specific beam element with implemented damage model was developed in implemented in the simulation using the bond data obtained from the analytical approach. The simulated parameters were macroscopic angle of repose, packing density, and surface conditions as a function of temperature and filling rate. The results showed that discrete element simulations were able to verify the existing published experimental data. Specifically, the simulation results showed that angle of repose of snow decreased rapidly with decreasing the temperature, the surface became very irregular due to the particles rotation and re-arrangement for lower falling speeds of particles, and density increased with depth of deposition. These findings were all matched with experimental observations.

The paper presents a mathematical expression of the sizes of the transverse and longitudinal cross-section surfaces and of the volume of the loose material spread on the surface of the conveyor belt before the transverse partition of the belt conveyor, inclination angle of which exceeds the limit transport angle permitted for the belt conveyor of a classic design. Volume and geometric shape of the lose material; transported in the trough (two-roller bench) loading profile; are impacted by the mechanical characteristics of the transported material, width of the conveyor belt, inclination angle of the side rollers, height of the transverse ribs and especially inclination angle of the conveyor. The maximal cross-section surface of the lose material filling at the conveyor with a smooth belt can be (for conveyor belts modified based on the shape of the trough) expressed as the sum of the cap cross-section surface and the surface of the bottom part of the belt filling. The paper describes the jacket curve of the of the cap cross-section using a parabola equation, and the surface curve of the bottom part of the belt filling using a line equation. The size of the cross-section surface of the belt filling along the longitudinal plane of the conveyor belt is defined as the difference between the inclination angle of the conveyor and the discharge angle of the transported material.

During 2020, a total of 140,336 new passenger cars were registered in the Czech Republic. Thus, at the beginning of 2021, the number of registered passenger cars in the Czech Republic reached 6,129,874. Even though the number of parking areas and parking spaces associated with individual types of buildings in the Czech Republic is determined pursuant to ČSN – Czech Technical Standards (ČSN 73 6056 - Parking areas for road vehicles and ČSN 73 6110 - Design of urban roads), most cities suffer acutely from an insufficient number of parking spaces. In the Czech Republic, dimensions of parking spaces are set by ČSN Standard 73 6056, or ČSN 73 6058 - Small, multi-story and mass garages. In densely populated urban and panel-block housing areas, it is almost a daily occurrence that drivers cannot find a place to park properly. One of the possible solutions that could cut down parking problems is "mass garages", single or multi-story, which efficiently make use of the built-up area and space. Parking in mass garages is based on the definition given in ČSN 73 6056. The basic length/width of perpendicular parking is 2.5 m/5.0 m (according to ČSN 73 6056), to which it is necessary to add area for spacing (depending on whether the parking is on an edge, next to a pillar, etc.). The next most efficient solution is "automated parking structures", which don´t require additional area for spacing around vehicles. In automated parking structures, vehicles are handled on steel pallets. The pallets are vertically transported by the computer control software to the designated floor by a lifting device, where they are horizontally moved to a transport device, which transports them to a parking rack cell. The pallet is inserted into / removed from the rack cell by a handling platform installed on the frame of the steel construction of the transport device. The pallet located in the rack cell must be fixed in the required position to prevent spontaneous movement of the pallet. The pallet is fixed by a locking device, the so-called mechanical brake. The paper describes three types of locking spring retainers, which can in some cases replace the existing structurally more complex brakes used in existing parking structures.

In the recent years, Additive Manufacturing (AM) is becoming an emerging technology and more and more material powders are available on the market. The knowledge of their specific mechanical behaviour is a fundamental aspect for their large-scale adoption, also considering the lack of reliable data and dedicated standards.In this work the High Cycle Fatigue characterization of a 17-4 PH Stainless Steel (SS) is presented. The cylindrical samples used were manufactured via Selective Laser Melting (SLM) technology using an EOS M280 machine. Two separate series of samples differing in terms of surface finishing were tested. The first series of samples was used in the as-build condition while the second series was machined in order to obtain a better surface finishing.The effect of the surface finishing on the fatigue behaviour of AM materials is fundamental considering that in most of the applications the parts – reticular or lattice structures with complex geometries – are set into operation in the as-build condition because a surface finishing is not feasible. The comparison of the results obtained for the two different series of specimens allows the quantification of the reduction of the mechanical performances due to the actual limits of the SLM technology. The fatigue limit was obtained with the short stair-case approach according to the Dixon statistical method. The maximum number of cycles (run-out) was set equal to 5000000. The left part of the Wöhler diagram was also studied by means of additional tests at higher stress levels.Additional quasi-static tests were performed in order to characterise the static behaviour.

This paper presents the study about the development of an innovative solution for road transport of high dimensions and lengths wire ropes. Currently these operations are limited by various constraints related both to the maximum weight and to the dimensions, even when using special vehicles, the passage of the load on the road becomes impossible. The proposed solution involves the use of two reels positioned on two separate trailers. In this case, the overall dimensions are reduced and the maneuverability of the load is considerably increased. The research is based on a concrete case in which the results relating to the sizing of the reels and the wire rope winding system are also reported, for the transport of a wire rope with a diameter of 125 mm and a weight of 400000kg. The research therefore shows that through this solution, which can also be extended to several vehicles connected to each other, the transport of wire ropes of large dimensions and length is achievable partially releasing the problem of dimensions and road travel.

The human condition is - ever since becoming, in an evolutionary sense, human-associated with running on two legs. Only in the latest human technical development, stairs have become increasingly present as they crystallize to be more suitable as an artificial environment. Although stairs are suitable for humans without walking handicap, they are not for wheel-driven vehicles, like Automated Guided Vehicle (AGV) in industry or personal accompanying support vehicles as an example. In this mixed human-machine environment a sort of stair climbing is essential for many logistic applications, as this is an, from the mechanical engineering point of view, essential step in mechanization and their automation. Only recently, a stair-climbing device has been issued a patent, called the "Malteserrollstuhl", which is designed for stair climbing for handicapped people. This patented mechanism could be further used for industrial applications. The goal of this work is to investigate the possible future directions and strategies that are most likely to be implemented, on the base of this patent, as the next steps towards logistical industrial applications.

This paper presents a method developed by Wielton company – a manufacturer of trailers and semi-trailers – for the optimization of semi-trailer's construction, supported by FEM analysis and the modern road simulator – a test stand included as part of the method for optimising semi-trailers. The aim of the research was to optimize the process of developing a technical measure in terms of shortening the time of implementing new products while guaranteeing high durability and functionality of the products. As a result of the optimization of the construction with the use of FEM analysis and the road simulator, the semi-trailer as a new product for sale is delivered quickly and possible defects of construction are eliminated on early stage of new product development. The method assumes the following stages of the development process: determination of input data to the process, development of a 3D model, FEM numerical analysis (static and dynamic), development of an optimized 3D model based on numerical analyses, construction of the first prototype, prototype validation tests using the road simulator and other test stands. Important feature of the developed method to optimise construction is connected with specific data achieved from FEM analysis and used in tests with the road simulator. The effect of using presented method is the elimination of 98% errors in construction and technology. These errors concern not only the key parts of the semi-trailer, i.e. the body and the frame, but also less important components, i.e. fixing of tanks and boxes, ladder, spare wheel basket, extinguisher mounting. The method to optimise semi-trailers developed in Wielton have many advantages, such as: limiting the risk of launching breakthrough solutions on the market, faster increase in vehicle competitiveness, optimizing vehicle construction, reduction of production time and costs, and as a consequence - faster implementation of new products, reducing the number of complaints and service costs, increasing the value and prestige.

Today, environmental protection and the rational use of natural resources have become growing challenges. One of these aspects is energy producing with less impact on the environment. For some applications the small wind turbines can be a solution. In this paper are presented some aspects regarding the design and manufacturing technology of 500 W vertical axis wind turbine blades. The turbine will be installed in the urban environment so that requirements regarding rotor aesthetics and noise level will be considered. The optimal geometric parameters of the turbine rotor were determined by specialized MathCAD and elaborated in 3D modelling software. For the blades the NACA 0018 airfoil was used with the chord length of 110 mm and is constant throughout the length of the blade. The blades are helical and are 1800 mm long. To estimate the aerodynamic performance of the turbine rotor, a computational fluid dynamics model was developed using ANSYS CFX finite element analysis software. The authors proposed a new method for rapid prototyping of blades using fused deposition modelling procedure. In order to increase the mechanical properties, the blades were covered with several layers of glass-fibres reinforced polymer. Estimation the blade strength to operating loads was performed using Ansys Workbench software. The modelling of the composite material architecture on the blade surface was performed using the special ANSYS Composite PrepPost module. Several simulations were performed with different number of layers and stacking sequences. In order to prevent rotor over engineering the maximum rotation speed of 400 min⁻¹ was accepted (equivalent to ≍12 m/s wind speed). Simulation of the blade strength to operating loads indicate values of around 40 MPa for shear stress (50% less than failure shear stress) and around 80 MPa principal stress (60% less than failure tensile stress). The maximum blade deformations of 3 – 4 mm shows that the blade is stiff enough at imposed operation conditions. For the blade manufacturing, based on the numerical analysis results, the configuration of the strength structure composed of 5 layers of GFRP was selected, which forms a total blade weight of 1895g.

Hard turning is a machining operation of finishing performed on material with a hardness higher than 45 HRC and it has been demonstrated to be a profitable alternative to grinding process allowing, respect to this latter, better surface quality, improved process control reliability, and faster production rates. The high pressure and sliding velocity at the tool-chip interface, in addition to the deformation energy generated, lead to the formation of high temperature zones localized in the cutting region. These thermal loads enhance harmful aspects on both cutting tool and machined material. On the tool, the abrasive-diffusive wear mechanism is promoted. On the workpiece, a local surface heat treatment of quenching is observed, upgrading the formation of a thin layer of over-quenched martensite, called white layer, due to its appearance under microscopical observation, that is undesirable due to its brittleness and related cracks generation. In addition to this, hard turning is usually performed in dry condition further augmenting machining temperature and tool wear rate. Because of the extremely high hardness of the machined materials, the employment of expensive ultra-high hardness cutting tools is mandatory. Thus, to make the process valuable, it is essential to optimize the tool usage by avoiding catastrophic failure and being able to forecast the tool wear evolution during cutting time as a function of the applied process parameters. One of the possible approaches for predicting the wear behaviour is finite element (FE) simulations of the turning process. In this work, the wear of polycrystalline cubic boron nitride (PCBN) tools when turning AISI 52100 hardened steel is investigated. An abrasive-diffusive wear model has been developed and implemented in a FE engine, by means of a dedicated subroutine able to update the geometry of the worn tool as a function of the cutting parameters, with the intent of simulating the tool wear behaviour, in terms of crater and flank wear extension. For the calibration of the model, the tool wear measurements achieved from an experimental campaign of orthogonal cutting tests have been used. The influence of process parameters on the wear rate has been examined, underlining that the most affecting parameter on tool wear is the cutting speed: the higher the cutting speed the higher the tool wear. Furthermore, it has been observed that the tool breakage was due to an excessive depth of the crater wear that modified the initial negative rake angle to a positive one. This modification changed the stress state of the tool from compressive to tensile, not well tolerated by PCBN tools, bringing to catastrophic failure. The tool wear simulation results are in good agreement with the experimental ones, validating the usability of the proposed computational methodology for crater and flank wear prediction. Therefore, the application of this technique allows the optimization of cutting parameters from a preventive FE simulation analysis avoiding the need of exploiting new costly and time-consuming experimental tests.

This study investigates the damage of a container chassis loaded with a container having a capacity of 22 thousand litres. The chassis was damaged during full-load operation. Based on the observed effects of damage induced in a longitudinal beam (longeron) of the container chassis, a hypothetical course of events was elaborated. An attempt was made to recreate the actual course of events by eliminating the reasons due to which the effects of damage significantly differed from those observed post factums. To this end, numerical finite element method (FEM) simulations were performed using the Abaqus software. The damaged longitudinal beam of the container chassis was modelled using three-dimensional (3D) solid elements. It was assumed that the beam had the same profile cross-section over its entire length. In the numerical model, the container chassis had a pinned support on the fifth wheel. Elastic elements were used to model the axle-supported regions of the container chassis with the wheels. The following three events were identified as the potential causes of container chassis damage: the container chassis was supported by the bumper on the ground when the wheels on the right side were in contact with the bottom of the road surface cavity; the container chassis was supported by the bumper on the ground when the wheels on the right side were not in contact with the bottom of the road surface cavity; the bumper was subjected to point impact during vehicle reversal. The numerical results demonstrated that for each of the proposed damage hypothesis, the highest reduced stresses were located in the very region where the container chassis damage was actually observed. It was found that the observed damage was most probably induced when the container chassis was supported on the bumper and there was no contact between the wheels and the road surface due to the presence of a cavity in the road surface. Moreover, analytical calculation results demonstrated that the force acting on the structural members of the container chassis in the analysed load case exceeded the force resulting from the static load of the structure by more than 2.5 times. The load-induced stress in the beam material significantly exceeded the strength of the structure.

Considering the constant advances in additive manufacturing, it makes sense to use this approach when creating a cutting tool. Currently, a lot of the tools used in machining are in the form of indexable inserts. This minimizes the amount of material used and ensures a swift change when a tool is worn out. Indexable inserts are currently made by pressing and sintering which requires a large investment in specialized mould tooling for each insert shape. This paper investigates an additive approach to making indexable insert blanks. This manufacturing process does not require mould tooling and offers a large degree of freedom when it comes to making inserts of diverse shapes. In this work, the process of manufacturing CCMT inserts out of MS1 steel (X3NiCoMoTi 18-9-5) is investigated. MS1 is not an ideal material for a cutting tool, however, the findings can be translated to blanks additively manufactured out of tungsten carbide, cermets or ceramics.

Cellulose is a biopolymer frequently implemented as fibers and membranes to fabricate high-performance and multi-functional composites. In this study, the molecular dynamics simulation is used to investigate the effect of CNTs on elastic modulus, ultimate strength, and toughness properties of silicon carbide nanotubes (SiCNTs) reinforced cellulose nanocomposite. Based on the simulation results, the temperature of the surrounding environment controls the stress transfer at the nanotube-cellulose interface. As the cellulose expands with increasing temperature creating more void regions at the filler-matrix interface, the load transfer from cellulose to nanotubes is reduced, leading to a noticeable reduction in tensile properties of cellulose composite. This behavior critically affects the tensile strength of cellulose composite reinforced with multi-walled CNTs (MWCNTs). The single-walled CNT with a high aspect ratio increases the cellulose composite's tensile strength and toughness, while the MWCNT introduces the most significant increase in cellulose stiffness. The difference in polarity between MWCNT and cellulose, along with the low aspect ratio of the external nanotube, would limit the capability of MWCNT in improving the tensile strength and toughness of cellulose. The single-walled SiCNTs are structurally unstable, and their stiffness degrades rapidly at high temperatures. Therefore, they are hybridized with CNTs to improve their stiffness and structural stability. SiCNT, which is hybridized with two CNTs, exhibits the best structural performance at 100, 300, and 500 K temperatures.

The fast rotation of the grinding wheel creates an airflow near its surface, which causes a deflection of the coolant jet. To obtain an efficient and reliable grinding process, it is necessary to consider the airflow when dimensioning the coolant supply. For this purpose, the airflow around rotating grinding wheels was analyzed and characterized. In this research the airflow velocities around the grinding wheel were measured using a Prandtl tube, high-speed records were used to analyze the interactions between coolant supply and the airflow and positions for an effective air deflection were examined. It is found that the influence of the airflow especially depends on the cutting speed and the porosity of the grinding wheel, the airflow is not constant along the width of the grinding wheel and without air deflection the coolant jet requires an exit velocity of at least 50% of the grinding wheel peripheral speed.

In the present study, fiber-metal laminates (FMLs) were formed by deep drawing after the metallic component was pretreated by laser structuring, sandblasting or anodizing in order to reduce the height of process-related wrinkles. Such surface texturing is commonly performed to improve the bond strength between the adhesively joined components of the FML by selectively increasing the surface area. This results in improved stability of the finished FML part due to increased resistance to delamination. First, the adhesion properties induced by each process were quantified using shear tensile tests. The shear strength was increased for all processes compared to the unstructured surface. The surface structures were characterized by roughness measurements and scanning electron micrographs. The surface properties adjusted by the different processes also contributed to the part accuracy of the deep-drawn FMLs. During forming, the matrix material contained in the unidirectional fiber composite plastic tends to build up against the forming direction, resulting in wrinkling between the flange and the cup shell. The increased adhesive strength of the metallic component impedes the flow of the matrix material and decreases the height of the resulting wrinkles. The height of the wrinkles was determined using a coordinate measuring machine on the formed FML cups.

Vehicle systems automation is an inevitable process as a result of the growing safety requirements and the trend of increasing car operation autonomy by reducing driver's influence. The paper covers the coordinated control operation of three active systems to assess the improvement of vehicle response. Direct yaw control through selective wheel braking (DYC), active front steering control (AFS) and active suspension normal force control (NFC) are included. The control method is fuzzy logic. The modelling is done in Matlab/Simulink, where 14-DOF nonlinear full vehicle model and 3-DOF reference model were introduced. Simulations were done for three manoeuvres: cornering event, single lane change and fishhook manoeuvre, at a speed of 130 km/h and dry road surface with adhesion coefficient of 0.9 was assumed. Coordination was done with adjusting scaling factors for each control. Results show improvements in the transient response behaviour of the vehicle compared with four vehicles: vehicle without any active system, vehicle with coordinated DYC and AFS, vehicle with coordinated DYC and NFC and vehicle with coordinated AFS and NFC. The biggest impact can be seen in results for sideslip angle and roll angle, coordinated cooperative control here gives lowest values in the transient period during the manoeuvre. Although it gives better results for the other variables as well. The goal of the coordinated cooperative control is fulfilled by improving the stability and handling of the vehicle, which helps the driver to maintain the feeling of manoeuvrability and the sense for the direction of movement of the vehicle. The system for direct yaw control through selective wheel braking has major impact but the coordination with the other two systems lowers the braking force per wheel. The system for active front steering control has lower impact but at lower speeds helps for maintaining better direction of vehicle movement. Considering these three active systems act simultaneously during high speeds and critical manoeuvres next step would be to define sequence of activation depending on the currently measured vehicle behaviour variables.

The paper presents the research results on the mechanical and tribological properties of geopolymers reinforced with natural fibers. As a matrix, conventional fly ash and dry construction sand in proportion 1:1 were used. Materials were activated with Na activator. Wasted flax tow in an amount of 0.25-1% by weight was introduced as a reinforcement. The test results showed that with the increase in the fiber content, the bending strength increases, while the compressive properties are comparable to the matrix material. Based on the obtained research results, the optimal content of flax tow was determined at the level of 0.5% by weight. In addition, the abrasion resistance of geopolymer composites was determined using the so-called Boehme shield. This test consists of measuring the change in sample height. The sample is placed on a disc sprinkled with abrasive powder, then pressed and put into rotation. The abrasion results showed that the addition of fibers in the form of waste pulps does not reduce the abrasion resistance, which should be considered as a positive effect. Research also revealed that wasted flax fibers could be successfully used as a reinforcing material in geopolymeric materials as an alternative to the utilization of waste fibers, and additionally may also have a positive effect on the mechanical and tribological properties of geopolymers materials.

Lead brasses, i.e. copper-based alloys with additions of zinc and lead, are widely used for production of specific components in the industry and commerce. Brass components are usually produced under hot conditions, i.e. via hot die forging (with the advantageous applications of induction heating), the semi-products for which are typically rods extruded from cast billets. Finally, the components are machined to their exact shapes. Nevertheless, such a complicated production process is prone to introduce defects in the structures of the final components. The herein presented paper deals with investigations of a brass component (pre-shaped gas valve, i.e. fitting) manufactured via hot die forging. The fitting exhibited cracking in a specific location after forging and the presented investigation attempts to characterize the factors, which could have possibly induced the occurring cracking, from the viewpoint of stress distribution. The experimental investigation focused on characterization of the structure in the vicinity of the cracked area with the particular focus on the occurrence of residual stress via scanning electron microscopy. This analysis was supported with the results of stress-strain distribution during forging acquired via numerical simulation of the die forging processing step (with implemented induction heating prior forging, in accordance with the real industrial conditions) performed using the finite element method (FEM). According to the acquired results, the cracking occurred in a location featuring local inhomogeneity of stress. The inhomogeneous distribution of stress in the particular location most probably developed as the result of the geometry of the forging die, which also introduced instabilities in the material plastic flow during forging.

Composites are generally materials consisting of a minimum of two phases or components, which are selected for their advantageous properties the combination of which provides the final composite material with better specific properties than those of (the original) single-phase materials and alloys. One of the composite types is clad composites, or laminated composites, consisting of layers of individual (metallic) materials. The presented study deals with laminated Al/Cu composite billets, which were processed via the severe plastic deformation (SPD) method of twist channel angular pressing (TCAP). The primary advantage of the SPD methods in general is their ability to introduce significant shear strain, resulting in substantial refinement of the grains of the processed materials, which consequently enhances their properties. The study is specifically focused on assessing the effects of single and double TCAP pass on the specific lattice rotations induced via the severe shear strain within the reinforcing Cu wires, which typically manifest in the changes in residual stress distribution and modifications in texture. The results revealed that after the first TCAP pass, the imposed strain was not homogeneous across the cross-section of the TCAP-ed composite sample as the individual Cu wires featured differences in the distribution of residual stress, as well as in the observed ideal texture orientations. Nevertheless, the second TCAP pass introduced substantial homogenization of the imposed shear strain, which manifested in a more homogeneous distribution of residual stress across the individual wires compared to the first pass. Also, the distribution of ideal texture orientations was more homogenized after the second pass, as all the Cu fibres exhibited the dominance of ideal shear A fibre texture.

This work investigates the influence of rotary swaging on creep behaviour and microstructure heterogeneity of P92 martensitic steel. Its as-received coarse-grained state was processed by rotary swaging at room temperature. The bar of 30 mm in diameter was reduced at room temperature down to 15 mm by rotary swaging. The value of equivalent strain imposed during rotary swaging was about 1.4. Microstructures were investigated by scanning electron microscope Tescan Lyra 3 equipped with NordlysNano EBSD detector operating at an accelerating voltage of 20 kV with specimen tilted at 70°. It was found that the processing by rotary swaging led to the formation of heterogeneous microstructure containing a mixture of fine nearly equiaxed grains and large grains, which were significantly, elongated parallel to the swaging direction. Constant load tensile creep tests in tension and compression were conducted at 923 K under different applied stresses. In order to evaluate the influence of microstructural heterogeneity on the creep behaviour, the creep tests were performed both in longitudinal and also transverse directions to the rotary swaging. The results of tensile creep tests revealed that specimens manufactured in the direction parallel to the rotary swaging exhibited significantly higher creep life and strain to fracture in comparison with the results measured in the transverse direction. The creep results showed that creep tests performed at medium stresses exhibit a pronounced minimum creep rate. The microstructure results suggest that creep behaviour depends on the microstructure coarsening during creep testing and the orientation of the grain boundaries with respect to the applied stress.

This paper addresses to a finite element analysis in dynamic conditions of a human ankle joint prosthesis based on a cam mechanism design. The proposed ankle joint prosthesis mechanism is a parameterized one and was designed in order to fulfil main human locomotion tasks namely walking during daily activities. A proper 3D CAD model has been developed and the proposed cam mechanism ankle prosthesis was modelled and simulated into MSC Visual Nastran environment. Results of simulations demonstrate the engineering feasibility of the design and validate the proposed parameterized prototype.

In this paper we are dealing with the methodology of design, preparation and implementation of quality features measurement of the production process. The aim is to develop a methodology for measuring parts in the structure. This article describes the procedure of the sample process management methodology.