Table of contents

Due to recent pandemic, 2022 8th International Conference on Applied Materials and Manufacturing Technology (ICAMMT 2022) was held virtually online on April 15th-17th, 2022. The decision to hold the virtual conference was made in compliance with many restrictions and regulations that were imposed by countries around the globe. Such restrictions were made to minimize the risk of people contracting or spreading the COVID-19 through physical contact. There were 160 individuals who attended this online conference, represented many countries.

ICAMMT 2022 is to bring together innovative academics and industrial experts in the field of Manufacturing Technology and Applied Materials to a common forum. The primary goal of the conference is to promote research and developmental activities in manufacturing technology and engineering materials, and another goal is to promote scientific information interchange between researchers, developers, engineers, students, and practitioners working all around the world. The conference will be held every year to make it an ideal platform for people to share views and experiences in Manufacturing Technology, Intelligent Manufacturing and Applied Materials and related areas.

During the conference, the conference model was divided into three sessions, including oral presentations, keynote speeches, and online Q&A discussion. In the first part, some scholars, whose submissions were selected as the excellent papers, were given about 5-10 minutes to perform their oral presentations one by one. Then in the second part, keynote speakers were each allocated 30-45 minutes to hold their speeches.

In the second part, we invited four professors as our keynote speakers. Prof. Yajun Liu, South China University of Technology, China. His research interest is in the areas of Mechanical system signal testing, analysis, characterization, control and performance optimization. The second keynote speakers, Prof. Honggang Dong, School of Materials Science and Engineering, Dalian University of Technology, China. His research area is Refilled friction stir spot welding of aluminum alloy to galvanized steel sheets. Prof. Weiwei Zhao, Wuhan University of Technology, China. His research area includes Characterization of mechanical and mechanical properties of polymer hydrogels, research and development of biomimetic electroactive hydrogels, and applications of polymer materials in microfluidic devices and biomedicine. Lastly, we were glad to invite Prof. Md. Akhtaruzzaman, Solar Energy Research Institute (SERI) of The National University of Malaysia as our finale keynote speakers. He studied on the design and synthesis of new organic heterocyclic compounds for EL device application. Their insightful speeches had triggered heated discussion in the third session of the conference. Every participant praised this conference for disseminating useful and insightful knowledge.

The proceedings are a compilation of the accepted papers and represent an interesting outcome of the conference. Topics include but are not limited to the following areas: New Materials and Advanced Materials, Advanced Design Technology, Manufacturing Systems and Automation and other related topics. All the papers have been through rigorous review and process to meet the requirements of international publication standard.

We would like to acknowledge all of those who supported ICAMMT 2022. The help and contribution of each individual and institution was instrumental in the success of the conference. In particular, we would like to thank the organizing committee for its valuable inputs in shaping the conference program and reviewing the submitted papers.

The Committee of ICAMMT 2022

List of Committee member is available in this Pdf.

All papers published in this volume have been 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 Publishing.

• Type of peer review: Single Anonymous

• Conference submission management system: Morressier

• Number of submissions received: 178

• Number of submissions sent for review: 172

• Number of submissions accepted: 100

• Acceptance Rate (Submissions Accepted / Submissions Received × 100): 56.2

• Average number of reviews per paper: 2

• Total number of reviewers involved: 30

• Contact person for queries:

Name: Xuexia Ye

Email: xx.ye@keoaeic.org

Affiliation: AEIC Academic Exchange Information Centre

The ultra-supercritical power generation technology with high energy efficiency and low emissions is one of the important ways to solve the current increasingly prominent energy problems in the context of international development requirements for carbon neutrality and the increasingly prominent energy shortage. Because of its excellent resistance to high temperature corrosion and organizational stability, S31042 is commonly employed in the most severe working environment of ultra-supercritical units. Due to its great resistance to high-temperature corrosion and organizational stability, S31042 is commonly employed in the most demanding components of ultra-supercritical units such as high-temperature reheaters and high-temperature superheaters. Various characterisation approaches were employed in this research to reflect the microstructure of S31042 heat-resistant steel in service under various time length conditions, and the hardness of S31042 heat-resistant steel was assessed under the corresponding service conditions. The results showed that the hardness of S31042 increased significantly with increasing service time, from around 160 Hv at the time of non-service to nearly 220 Hv after 75360 hours of service. The continuous distribution of uniformly sized M₂₃C₆ phase on the grain boundaries of S31042 developed toward grain coarsening after service, but the precipitation strengthening effect produced by the nanoscale secondary NbCrN phase appearing in the grains was the main reason for the increase of the hardness value of S31042, according to the microstructure of the material.

The failure of the thermal protection structure is very important to the safety of the aircraft structure. In order to accurately predict the flexural behavior of the aerogel sandwich thermal protection structure, first of all, for the sandwich structure in the form of statically indeterminate beam with variable cross-section, the beam theory considering the transverse shear deformation of the core layer was deduced. Secondly, by comparing the deflections, the forms of deflection curve and the maximum strains of the upper panel, the accuracy of the theoretical prediction was analyzed. Then, according to the requirements of heat protection and integrity of the thermal protection structure, the optimization analyses of the parameters of the core layer, such as the thickness, the density and the elastic modulus, were carried out. The results showed that the beam theory considering the transverse shear deformation of the core layer had better prediction accuracy. The maximum deflection error was the smallest, which was -17%, and the form of the deflection curve was the most reasonable. Within the range of the physical parameters of the core layer studied, the theoretical basis and guiding direction were given for the regulation of the performance of the aerogel core layer.

FSM (field signature method) is a new non plug-in on-line monitoring method for pipeline corrosion. The traditional FSM corrosion monitoring equipment is generally a single machine to copy data or collect terminal client wireless transmission data, which is not convenient for data management. In this paper, cloud service is introduced into the monitoring system, and the FSM corrosion monitoring system based on cloud server is developed, which realizes the functions of real-time, online and remote control. The monitoring system can obtain the current status data of the monitored pipeline in real time, and calculate the corrosion parameters of the pipeline according to the data sent back by the measuring device. The system can draw trend diagram and morphology diagram according to the calculated corrosion parameters, display database data tables and relevant charts, and send monitoring information regularly.

Isogeometric analysis (IGA) is a promising alternative for finite element analysis (FEA) with simplified design-through-analysis workflow. However, existing models in CAD software cannot be used directly for analysis. Parameterization of the input geometry is necessary to transform it into an analysis-suitable model. But it is non-trivial to produce smooth non-folding results. In this paper, we present a novel parameterization scheme based on the hyperelasticity analogy in solid mechanics. Compared with other state-of-the-art techniques, numerical examples prove that the proposed method guarantees bijective results with excellent smoothness.

The application of composite materials in the primary structures of large aircraft fuselage is a development trend in recent years. As an indispensable structure in design and structure selection, accurate and efficient evaluation of its performance is of great significance to reduce the research cost. In this paper, the bearing capacity of stiffened curved composite panel is calculated through an improved engineering calculation method, and the effectiveness of the method is verified by test, which provides technical support for the rapidly design and selection of stiffened curved composite panels.

In order to ensure the stability of the car, ANSYS software is used by Start Point racing team of Beijing institute of technology Zhuhai to analyze the car driving wheel core, the results show that the core of the rear wheel made of pure aluminum alloy material conform to the requirements of the car to the deformation, also meet the requirements of the material properties of stress, but cannot meet the requirements of the wear and tear, so adding interference fit bushing, can improve its wear resistance.

Femtosecond laser etching is applied to fabricate cylindrical, quadrangular and circular hole micro-structures to explore the variation patterns of their reflectivity. The results show that the cylindrical and quadrangular texturing structures have the optimal anti-reflection effect (the reflectivity is always below 6%) in the wavelength range of 350-1000 nm, which is of reference value for the study of fabricating low-reflectivity texturing on monocrystalline silicon surfaces.

In order to meet the urgent needs of aluminum alloy integral shell, a new forming process is required to solve the problem of splitting at room temperature. The plasticity of aluminum alloy is significantly improved at cryogenic temperature, and a novel cryogenic forming method was developed recently. In this paper, a cryogenic forming unit was established to study the cryogenic drawing behavior. The effects of sheet diameter on the wrinkling and deformation behaviors were analyzed by experiments and numerical simulations. The study showed that a spherical shell with a diameter of 200mm and a thickness-diameter-ratio of 1.0% could be formed at -160°C, which split at room temperature. The drawing depth was increased 74.3% at cryogenic temperature. The tendencies of wrinkling and splitting were controlled by the appropriate sheet diameter. It is concluded that cryogenic deep drawing has great potential for forming aluminum alloy integral shells.

The main steam system(VVP) support of nuclear power plant protects the main pipe by welding the guard plate on the main pipe. This paper takes defect treatment of the VVP main steam system(VVP) pipe and support weld in a nuclear power plant as an example. From the analysis of the effective mechanism of the weld generation to the proposal, discussion and implementation of the final scheme, the technical points are comprehensive described, defect types were determined by penetrant testing and metallographic observation, and further root reason analysis was carried out. Accordingly, the defects are eliminated by technical means to avoid the expansion of defects and ensure the safe and stable operation of the unit. The analysis and treatment scheme of the defects in this project provides a technical scheme for inspection and maintenance in the nuclear power field, and provides an important reference for the future treatment of defects.

DC microgrid has received extensive attention and research because of its natural advantages of improving the consumption efficiency of distributed power sources, and in line with the development trend of clean environment and intelligent operation of power grids in the future. However, short-circuit fault protection of DC microgrid is a major challenge for the development of microgrid. Therefore, the author proposes a DC solid-state circuit breaker with a positive channel metal oxide semiconductor as the main switch, and through simulation, it is verified that this solid-state circuit breaker is feasible. The experimental results show that when the proposed solid-state circuit breaker is normally turned on, the positive channel metal oxide semiconductor is completely turned on, which has no effect on the power flow in the DC microgrid; when a short-circuit fault occurs in the DC microgrid system, the short-circuit current is used to couple the energy, the positive channel metal oxide semiconductor is reliably turned off. The stability and reliability of the system are improved, and it can be applied to the short-circuit protection of the DC microgrid, and has a good application prospect.

To explore the application and development of ultrasonic non-destructive testing technology in composite solid propellant materials, the theory is combined with the principle and method of ultrasonic non-destructive testing technology and the material characteristics of composite solid propellant; Based on ultrasonic A-scan, the experimental testing of propellant grain with multiphase structure, complex properties and high attenuation was carried out using pulse reflection method and penetration method. For the testing system with probe emission frequency of 1 MHz and gain adjustable range of 60 dB, the thickness of propellant grain is recommended to be 10 ~ 50 mm for the pulse reflection method to effectively observe the first bottom echo and the second bottom echo, and the thickness of propellant grain is recommended to be less than or equal to 100 mm for the penetration method to effectively observe the transmission waveform. The coupling modes of ultrasonic testing technology are further analyzed, and the effect test is carried out. In addition, based on the pulse reflection method of direct contact coupling, the sound velocity of propellant grain is measured with probes with different frequencies. The results show that the higher the probe frequency is, the smaller the sound velocity of propellant grain is.

In orbit deployment and profile maintenance are the most important functional requirements in the development of loop antenna If the antenna cannot be deployed in orbit, it will lose the signal transmission function, and the profile in orbit holding function is related to whether the antenna can stably transmit electromagnetic signals. The mesh tension (main mesh tension, rear mesh tension and tension arrays tension) is the key means to maintain the profile stability in orbit. At the same time, it is also closely related to the rod load and the maximum motor driving force in the process of antenna deployment. Based on the theory of flexible multi-body dynamics, the dynamic modeling of the deployment process of ten meter loop deployable antenna is established in this paper On this basis, the influence of mesh tension on the deployment dynamics of loop antenna is analyzed by using the control variable method, and its related variation law is obtained. This study can provide guidance for the tension adjustment in the profile adjustment stage of the ring antenna, so as to shorten the development cycle, and can also predict the deployment of the antenna in orbit.

For the new assembled sealed cabin door of space station, its structural characteristics, sealing working principle and sealing assembly and adjustment difficulties are analyzed. The static simulation based on the minimum loading point deformation is studied to obtain the minimum compression ratio boundary. Based on the maximum operating force, the sealing stress calculation and simulation analysis are carried out to obtain the maximum compression rate boundary. It realizes the transformation of multiple open constraints into the compression rate interval, which effectively improves the assembly and adjustment accuracy and efficiency of the assembled cabin door.

Al-18Si-X (X=Mg, Ti, Ni) composite tubular castings were prepared by centrifugal casting. The microstructure of cylindrical casting of Al-18Si-X composite was observed along the radial direction, and the segregation behavior and distribution characteristics of primary particles formed in different alloys under the action of centrifugal field were studied. The results show that the in situ particles in Al-18Si-7Mg, Al-18Si-7Ti, and Al-18Si-7Ni tubular castings have different segregation behaviors under the action of centrifugal field, which results in the formation of particle reinforcing layers in different regions of the castings. It is found that the volume fraction, size and particle morphology of primary particles in particle reinforcement layer of different castings are different.

Negative Gaussian curvature in deformed surface subjected to concentrated loads is a key weakening factor on the surface accuracy of umbrella antennas. The negative impacts can be mitigated by increasing the bending rigidity of the reflector surface. Thus, firstly, this paper is concerned with the effect of bending rigidity on Gaussian curvature based on the analysis of bending circular thin plate with large deflection. Exact expressions of Gaussian curvature for deformed circular thin plates are derived using the analytical solution of the von-Karman plate equation and the properties of positive and negative for Gaussian curvature is investigated. After solving the zeroes of Gaussian curvature using the Newton iteration method, Gaussian curvature distribution of the deformed surface is obtained.

In order to reduce the cost of electric control box and improve its beauty and universality, the design structure of a mine explosion-proof electric control box is improved in view of the disadvantages existing in the use of a certain type of mine explosion-proof electric control box; At the same time, for the problems of heavy self-reliance, high processing cost and poor heat dissipation of the existing electric control box, by changing the material, plate thickness, stiffener treatment at the appropriate position, or changing the plate structure of the box, the stress analysis is carried out under the pressure conditions, and the box with two schemes meeting the service conditions is designed and improved. At the same time, the manufacturing cost and heat dissipation of the box before and after the improvement are compared, which can be used as a reference for the design of electric control box in the future.

This paper studies the control strategy of hybrid energy storage to suppress power fluctuation of direct-drive wind turbine based on static var generator, and proposes a grid-connected power oscillation suppression of hybrid energy storage direct-drive wind turbine based on static var generator (SVG). Method, the static var generator is mainly to solve the reactive current generated by the large and impact load and the resulting reactive power, and the SVG connected in parallel with the fan outlet busbar performs reactive power coordinated control to support the grid voltage. This control strategy control The lead-acid battery compensates for the intermediate frequency power fluctuation and the super capacitor (SC) quickly absorbs the high frequency power fluctuation, thereby smoothing the wind power and improving the power quality. sexual demands. Finally, a system simulation model is established in the Matlab/Simulink environment to verify the effectiveness of the proposed method.

Structures with dissimilar materials can make full use of the advantages of each material. However the welding of the aluminum alloy plate and plastic plate are difficult due to high difference in melting point. The friction stir lap welding method is selected in this paper. The numerical model was built to study the heat transfer behavior inside the plates, as the temperature plays an important role in determine the weld quality. The model was validated through experimentally measured temperature results. The influence of welding process parameters such as welding speed, tool rotating speed and downward feed was analyzed. It was found that under the welding speed of 100r/min and downward feed of 0.3mm/s, sound weld was produced.

The characteristics of microstructure and properties of Cr12MoV die steel with austempering were investigated by scanning electron microscope, electron backscattered scattering detection, X-ray diffractometer and Rockwell hardness tester. The results indicated that the tempering process reduced retained austenite apparently, especially after direct quenching process which decreased the volume fraction of retained austenite from 24.8% to 8.5%. Prolonging the holding time of isothermal quenching from 3h to 5h promoted the transformation of lower bainite and reduced the content of residual austenite. The bainite formed in isothermal combined with the secondary hardening caused by austenite decomposition made the hardness of 55.9-56.6HRC similar to that of 57.2HRC by direct quenching and tempering.

In order to evaluate the static strength and reliability of touring car frame structure, based on the finite element theory and the simplified model, this paper establishes the finite element model to numerically simulate the static strength reliability of the structure under four common working conditions of bending, torsion, braking and turning. It analyses its maximum stress under the limit load, and finds out the weak area of the structure, The corresponding structural optimization scheme is proposed, which largely replaces the physical prototype verification process in the transmission design, greatly reduces the product R & D cycle, and provides theoretical support for the structural optimization of the whole vehicle.

The coating process in ceramic stereolithography is one of the principal sources of inaccuracy in the height dimension. The coating in stereolithography is a layer-by-layer build-up process, so the thickness of one layer coated is influenced by the previous layer and affects the thickness of the next layer. If inconsistent layer thicknesses exist, they will result in the poor quality of the final product. This paper analyzes the coating process of the slurry-separated system based on a simple 2D model and Navier-Stokes equations, presenting the theoretical equations of layer thickness for the commonly used blade types. Given the characteristics of layer-by-layer coating in stereolithography, the theoretical equations should be constantly iterated to obtain the thickness of each layer. This paper discovers the initial blade gap has a significant impact on the layer thicknesses by theoretical analyses. With the verification of experiments, the results shows that the presence of the unreasonable initial blade gap may lead to large fluctuations in layer thicknesses of the first few layers, and the coating in stereolithography is a "self-regulating" process with a tendency to the desired thickness. The larger the desired layer thickness, the worse this "self-regulating ability" is. This paper defines a coefficient of blade gap and proposes that using the coefficient of blade gap to determine a reasonable initial blade gap based on different working conditions can effectively control the consistency of each layer thickness.

A lack of control over the relative orientation of donor and acceptor moieties in solid films is the main reason for poor electroluminescence efficiency found in most D-σ-A patterns. In this study, adamantane was introduced as the linker for the construction of a D-σ-A system since its rigid but non-conjugated nature. For a systematic study, the same donor (9,9-dimethyl-10-phenyl-9,10-dihydroacridine, DMTPA) and acceptor (2,4,6-triphenyl-1,3,5-triazine, TPZ) block were attached at different sites of the adamantine molecule, forming three kinds of configuration including face-to-face (FF), head-to-tail (HT), and chair (CH) style. DFT/TD-DFT simulation was carried out to investigate the electronic structures, optical characteristics, and charge transfer (ICT) properties of these three designed molecules. Attributed to a non-conjugated adamantane linker, the conjugation between donor and acceptor was disrupted for either of these molecules, resulting in high triplet energy of 2.79, 2.99, and 3.10 eV, respectively. Among them, the face-to-face style molecule presents the smallest ΔE_ST and greatest charge transfer excitation from donor to acceptor, suggesting an excellent potential for thermal activated delayed fluorescence (TADF). Face-to-face type molecule is a good option for a high-performance blue organic light-emitting diode (OLED) host material based on these results. Our investigation may open a door for designing new host molecule with other donor and acceptor groups to further enhance the efficiency and longevity of OLEDs.

Ni₄₈Co₃₀Cr₁₆Al₃Ti₃ HEA was made by suspension melting, and treated by different heat treatment methods. The microstructure, phase composition and microhardness of the prepared alloy samples were analyzed by means of XRD, SEM, X-ray energy spectrum analyzer and microhardness tester. And the results show that the Ni₄₈Co₃₀Cr₁₆Al₃Ti₃ HEA after different heat treatments has face centered cubic structure, and the alloy structure presents dendrite morphology. Under different heat treatment conditions, the diffraction peaks of the alloy samples treated by secondary aging at (800°C×12h+1000°C×4h) are the highest and strongest, and the precipitates of the alloy samples treated by aging at (800°C×12h) are the most dense and subtle. The distribution of elements in the samples are relatively uniform, but after heat treatments, part of the alloy grain structure and grain boundaries dissolve, the degree of dissolution increases with the increase of heat treatment time, so that some elements are not distributed in the alloy structure and grain boundaries. The microhardness value of alloy samples first increases and then decreases with the prolongation of heat treatment time, and the microhardness values of the samples were the highest after aging treatment at (800°C×12h), which was 357HV₁.

Based on Coupled Eulerian-Lagrangian method, the impact characteristics and strength evaluation of high speed multi-angle oblique water entry of slender body were studied. In order to solve the complex fluid-structure coupling problem and large deformation problem, the Lagrangian grid is used to divide the slender body structure grid, and the Euler grid is used to divide the fluid grid, the effectiveness of the method is verified by comparing with the experimental results. Furthermore, by simulating the impact process of multi-angle water entry, the time-history curves of acceleration, stress and strain at the head position of the slender body were analyzed, and the strength evaluation was carried out to verify the structural safety combined with the residual strength formula. The results show that there is a positive correlation between the impact load and the water inlet angle, and the larger the water inlet angle, the greater the impact load; the residual strength factor of the slender body is positive at 15° and 20°, and the structure is safe, at 30°, the residual strength factor is -0.203, and the structure is unsafe.

With the continuous development of science and technology, people begin to pay attention to environmental protection. At present, there are many fields causing environmental pollution, among which printing and dyeing wastewater has become the most difficult to degrade in our daily life due to the complexity and instability of organic substances in its water. The seriousness of printing and dyeing wastewater pollution has a great impact on our living ecological environment. As a typical material in semiconductors, titanium dioxide has the advantages of low price, strong compatibility, non toxicity, self-cleaning and stable physical and chemical properties. These advantages determine that titanium dioxide has absolute advantages and deeper potential in the field of photocatalysis. There are a variety of types and forms of titanium dioxide, including titanium dioxide film, powder, particle, fiber and so on. The flexible titanium dioxide nanofiber membrane prepared by electrospinning has the characteristics of high specific surface, large pore size and high transmittance. Flexible titanium dioxide nanofiber membrane is more available and recyclable and can avoid secondary pollution as well. Therefore, the preparation and selection of reasonable photocatalytic materials is also a key step in the field of photocatalytic technology.

Virtual material is a dynamic model of mechanical contact surface, which is suitable for finite element simulation. This method can characterize the stiffness and damping of the contact surface well by using fractal geometry theory to describe the contour of the contact surface. Based on standard W-M function, we verify the accuracy of the fractal dimension calculated by wavelet transform, and then fit the fractal dimension of machined surfaces with different roughness. Using the fractal dimension, we calculate the virtual material parameters to establish the finite element model of the unit specimen. Finally, we carry out the experimental modal analysis to examine reproduce the virtual material method.

In this paper the friction and wear of 23CrNi₃Mo carburized steel under water lubrication were studied. The friction and wear properties of carburized steel sliding with stainless steel, GCr15, Al₂O₃ and ZrO₂ balls were analyzed by tribometer, 3-D topography and SEM. The results show that compared with other materials, ZrO₂ and carburizing steel have better tribological properties. Compared with Al₂O₃, the wear depth of carburized steel sliding with ZrO₂ is reduced by 41% at the load of 2 N and 50% at the load of 10 N. In the load range of 2N-10N, the wear rate of carburized steel is the lowest when rubbing with ZrO₂, and it gradually decreases when the load increases. Combined with SEM and Raman spectrum analysis, Oxide film was formed on the surface of carburized steel during the sliding test of ZrO₂ and carburized steel. This oxide film was mainly composed of Fe₃O₄ and Fe₂O₃, which effectively reduces the friction coefficient and wear rate of 23CrNi₃Mo carburized steel under water lubrication.

Charge density wave(CDW) is an important physical phenomenon and has always been one of the significant research contents in condensed matter physics. The study of CDW helps people to have a deeper understanding of the interactions between various particles in low-dimensional systems. At the same time, the control of CDW in the material can effectively control the physical properties such as superconductivity. The study of CDW originated from one-dimensional and quasi-one-dimensional materials. This paper introduces the origin of CDW and the main formation mechanism of CDW at this stage. Discuss the common regulation methods of CDW and the competitive relationship with other physical properties. Finally, the possible research directions in related fields and the potential applications of CDW are prospected.

The spray formed 7055 aluminum alloy with 4.2mm thickness was welded by laser-arc hybrid heat source. The microstructures and properties of the welded joints are studied. The results show that the weld appearance is very full and the weld zone is primary composed of equiaxed crystals. Those equiaxed crystals morphology in different positions are also different, and only a small amount of columnar crystals are locally formed in the fusion zone. The average microhardness values of the weld zone and the heat affected zone are lower than that of the base metal, reaching 64% and 82% respectively. The average tensile strength of welded joints with as-welded state reaches 51% of the base metal. However, the tensile properties of the joints are significantly improved after the two-stage solution and aging heat treatment, and the average tensile strength can reach 515MPa, which was about 84% of the strength of the base metal.

Because the screw surface is slender and complex, it is difficult to process by traditional polishing methods. In order to improve the surface quality of screw, the abrasive water jet polishing (AWJP) technology was used to polish 38CrMoAl steel, which is commonly used in screw. The effects of different inlet pressure, target distance and abrasive particle size on surface roughness are analyzed. The experimental results show that with the increase of inlet pressure, the surface roughness first decreases and then increases. With the increase of target distance, the surface roughness first decreases and then increases. The smaller the abrasive particle size, the better the polishing effect.

Herein, we report a dual-modified organic-inorganic separator as an alternative to polyolefin commercial separator for lithium metal batteries. This composite separator exhibits high thermal stability properties due to the use of an engineering plastic matrix of poly (arylene ether nitriles) (PEN). The dual hydrophilic modification strategy also allows the separator to have a high ionic conductivity and a low interfacial impedance. With this new separator, lithium-metal batteries have high charge/discharge capacity and high-rate performance. Moreover, Li/Li symmetric cells display long-term stability and phenomenon of suppressing the lithium dendrite in lithium-metal batteries.

Ion thruster is a revolution technology with potential applications in space mission but the thruster's operation lifetime is limited by the sputtering from thruster components. In this work, molecular dynamic simulations are performed to explore the dependence of deformation characteristics of an aluminum surface on incident angle and kinetic energy under low-energy xenon-ion impact. The fraction of non-12-coordinated atoms is used to quantitatively characterize the microstructural evolution and defect density levels. It is found that defect density level has a linear relation with incident energy, and there exists a critical incident angle around 20°, at which the aluminum surface has the maximum defect density level. In addition, a collision model is developed to theoretically reveal the physical mechanisms behind the dependence. Our findings may helpful in developing long endurance electric propulsion devices for practical applications.

As an absorbable and implantable biomedical material, magnesium alloy has made great progress in the application of biomaterials in recent years because of its excellent biocompatibility and biomechanics. At the same time, the disadvantages of magnesium alloy materials are more obvious. Because of the large linear expansion coefficient of magnesium alloy, the high temperature during dry cutting will lead to the degradation of machined surface quality. In addition, due to the active chemical properties of magnesium, cutting fluid is easy to cause corrosion of machined surface, and it is easy to react with water in cutting fluid to release hydrogen, causing accidents. In this paper, the effect of cryogenic milling with liquid nitrogen on the surface quality of magnesium alloy was studied by comparing the prepared magnesium alloy in different cooling environments, and the surface roughness model was established for prediction and verification. The results show that the roughness value of the surface machined by liquid nitrogen cryogenic milling is smaller than that of dry cutting, and the hardness value is larger than that of dry cutting, which is very beneficial to improve the surface quality of workpiece. This paper aims to improve the low-temperature machining process of magnesium alloy, and provide theoretical and practical guidance for the preparation, processing and application of high-performance medical magnesium alloy.

To obtain low k materials with good comprehensive performances, fluorinated poly(aryl ether nitrile)s containing pendant cyclohexyl groups (FCPEN) have been designed and synthesized via nucleophilic aromatic substitution polymerization. The polymer exhibits excellent dielectric properties with a dielectric constant of 2.96 and a dielectric loss of 3.95 × 10^-3 at at 1 MHz. Besides, FCPEN displays satisfactory thermostability with a 5% weight loss temperature (T_d5%) of 489 °C and a glass transition temperature (T_g) of 191 °C. The resultant film shows good mechanical performance and optical transmittance. The outstanding comprehensive properties indicate that FCPEN is a promising low k material for the fabrication of microelectronic devices used in 5G communication.

Polyarylene ether nitrile (PEN) is a new type of super engineering polymer with excellent high-temperature resistance, radiation resistance, good electrical insulation, and mechanical properties. In this work, boron nitride (BN) and copper phthalocyanine (CuPc) hybrids were integrated as fillers, which were further dispersed into PEN matrix by solution casting method to obtain a series of PEN composite films. The successful preparation of hybrid fillers was proved by means of X-ray photoelectron spectroscopy and scanning electron microscopy. The test results of the dielectric properties of the composite films show that the CuPc-BN/PEN films exhibit good dielectric properties. When the mass fraction of filler reaches 10 wt%, the dielectric constant of the PEN composite film increases by 17%. This study shows that the composites composed of modified BN and PEN has excellent dielectric properties and has great application potential in heat-resistance thin-film capacitors.

In this paper, dimethyl sulfoxide (DMSO) was used as the hydrogen bond inhibitor to realize the co-dissolution of polyvinyl alcohol (PVA) and tannic acid (TA) in the casting solution. When the casting solution was placed in a water coagulation bath, the hydrogen bond cross-linking between PVA and TA is re-established, realizing the in-situ hydrogel network modification of the ultrafiltration membrane. The results show that the as-prepared membranes have underwater super-oleophobic properties and exhibit excellent anti-fouling ability during the separation of oil-in-water emulsions.

In order to improve the dynamic performance of FSAE racing car, the finite element analysis and lightweight design of racing sprocket are studied in this paper, Firstly, the parametric modeling of the big sprocket of FSAE formula racing car was carried out, and then the finite element modeling and analysis of the initial design scheme was carried out based on ANSYS Workbench software. The lightweight design was designed on the premise of meeting the design requirements, and the reliability of the sprocket design was ensured. Finally, the strength, safety factor and life of the optimized model were simulated and verified, the sample was manufactured, and the physical experiment was carried out by assembling and integrating the model into the racing car. The results show that the optimized sprocket meets the work requirements.

The squeeze casting process is an advanced technology, which is suitable for a wide range of alloys including Al-Cu-Mg alloys. The high pressure in squeeze casting process both refines the microstructure and enhances the mechanical property of the alloys. The heat transfer and solidification process are complex with the chilling mould and pressure of machine punch. This results in the inhomogeneous microstructure and property in casting alloy. This study focuses on the distribution of microstructure, chemical composition, and hardness of Al-Cu-Mg alloy along the radial direction of casting. The composition and area fraction of eutectic phases are characterized. Moreover, the relationship between the microstructure and mechanical property was also analysed to show the characteristic of microstructure in squeeze casting process.

The boron-containing carbon aerogels with excellent properties are reported: The precursor of carbon aerogels was modified by boric acid. Compared with the unmodified carbon aerogels, the compressive strength of the prepared carbon aerogels has been significantly improved, reaching 4.57MPa. The density of the carbon aerogels is between 0.253-0.287g/cm³, and the thermal conductivity is also kept at a low level of 0.057-0.062 (W⋅m^-1⋅k^-1). Excellent mechanical and thermal insulation properties make the prepared carbon aerogels have a good application prospect.

In this study, a facile co-modification of dopamine (DA) and methylphenyldimethoxysilane (MPDS) was utilized to functionalize barium titanate (BaTiO₃) nanoparticles with organic functional film. With the organic film coated on surface of BaTiO₃, the compatibility between BaTiO₃ and PEN matrix was greatly enhanced, which led to the promotion in thermal and dielectric properties. Results indicated that the glass transition temperature (T_g) of BaTiO₃@(MPDS+PDA)/PEN composite showed increment from 171.9°C to 181.2°C. Besides, the dielectric constant of PEN composite containing 20 wt.% of BaTiO₃@(MPDS+PDA) improved to 9.32 with a relative low dielectric loss compared to BaTiO₃/PEN under the same additive ratio.

Inorganic adhesive is widely used in the sealing and connection of electronic devices. Its insulation is highly important in the performance of installation. In this paper, the insulation resistance and tensile strength of different composite silicate samples were measured by test machines. The morphology and surface composition were analyzed by electronic microscope and energy spectrum analyzer. The results show that: In a humid environment, the resistance insulation of adhesive increases with the rising of heat treatment temperature, and decreases with the increment of wet environment. When the modulus ratio of colloidal liquid is in the range of 7.2~9.1 and the heat-treatment temperature is larger than 600°C, the effect of moisture resistant is remarkable. The tensile strength of adhesive deteriorates with the increasing of humidity. Furthermore, with ascending heat treatment temperature, the tensile strength rises when the modulus ratio of adhesive is less than 7.2, and declines when it is more than 9.1.

Using the two-way flow-heat and one-way thermo-solid coupling simulation analysis methods, the designed thin-film thermocouple is analyzed by finite element, and the flow field, temperature field, and structural field inside the sensor are obtained. The high-temperature redundant thin-film thermocouple working simulation test shows that: The response time of the designed thin-film thermocouple is less than 2 seconds, and the stress and deformation are within the required range under the operating temperature load and wind load.

Taking the tensile strength as the inspection index, the single-factor influence experiment was carried out on the addition of phenolic resin and the four factors of laser power, laser scanning rate and sand thickness in the sintering process, and the optimal level combination of each factor was obtained: the addition of phenolic resin. 5%, laser power 38W, laser scanning rate 3400mm/s, sand thickness 0.25mm.

In order to improve the flowability of lithium hydroxide powder, the lithium hydroxide powder in a company was selected under the conveying condition. The degree of circularity was used to quantitatively characterize the micro-morphology of the powder, and the influence of particle size on the flowability of lithium hydroxide powder was studied by the angle of repose method, HR method and Carr flowability index method. The results show that the lithium hydroxide powder gets better with the increasing of particle size. But the flowability of fine particles (≤ 100μm) is poor, while the flowability of medium particles (100~200μm) and coarse particles (≥ 200μm) is good. Based on the experimental results. It is suggested that the inclination angle of silo should be designed to be no less than 50⁰ and the content of powder with particle size less than 100μm in lithium hydroxide should be controlled to improve the conveying efficiency of lithium hydroxide powder.

In this paper, aiming at the chemical reaction system of solid-phase oscillating combustion, the basic dynamic behavior of laser system in terms of bifurcation diagram, Lyapunov exponent and complexity C0 is analyzed by using Matlab software, and the chaotic characteristics and sensitivity to parameters of the chemical reaction system of solid-phase oscillating combustion are expounded.

As a key part of the solid rocket motor, the nozzle always withstands a series of problems such as high-temperature, high-pressure, and chemical erosion and faces more severer environmental challenges. So its Stability plays a vital role in the normal operation of the engine. This paper takes the engine nozzle throat lining as the research object, uses the ANSYS to establish a carbon/carbon composite throat lining model in the ACP module, and analyzes the stress and displacement of the throat lining in a high-temperature and high-pressure environment. The experimental results show that under the high-temperature condition of 3500°C, the maximum stress value is 2734.8MPa, and more than 96% of the area is below 1000MPa, lower than the prescribed stress threshold. The superiority in the performance of the throat lining prepared for carbon/carbon materials is verified, and the structural integrity of the throat lining can still be guaranteed under high-temperature conditions.

Metallographic analysis is one of the means of testing and analyzing materials. To conduct metallographic analysis, we must prepare samples that can be used for microscopic observation. It is important to select and prepare representative samples, which is directly related to the correctness of microstructure analysis of metallography apspecimensimen. In this paper, the preparation process of the ferrocarbon alloy metallographic sample was analyzed and studied in detail, and some common defects were pointed out. The preparation process includes sampling, inlaying, polishing, polishing, and corrosion. Then, taking a silicon aluminum alloy (YZAlSi10) as an example, the preparation process is described, and the matters needing attention in the preparation process and the elimination of metallographic defects are analyzed. Finally, the accurate and clear microstructure of the metallographic structure is restored.

In order to realize lightweight manufacturing of gear parts, the cold extrusion forming process of steel-aluminum composite metal gears was studied. Using numerical simulation software Deform, the effects of five steel rings with different thicknesses on forming pressure and shapes of formed forgings were compared. The simulation results showed that final forming force of the gear was smaller and the radial deformation degree of steel ring was larger when using thinner steel ring. This radial deformation degree was characterized by height difference between the convex and the concave in steel-aluminum bonding position, and great deformation presented as obvious bimetal occlusion. The physical experiment verified numerical simulation results, and meanwhile found that the thickness of steel sleeve had an important effect on bonding tightness of steel-aluminum contact surface of formed part and the composite gear formed by thin steel ring had a gap at tooth tip between steel and aluminum. Comprehensive analysis suggested the ratio of outer diameter to inner diameter (R0/Ri) of steel sleeve reflected different deformation regularity. Consequently, the thick-walled axial compression model was used to analyze forming process of steel sleeve with high R0/Ri ratio, and the thin-walled cylindrical shell model was used to analyze forming process of steel sleeve with low R0/Ri ratio. The axial compression of thin cylindrical shell produced local buckling deformation, which led to the appearance of gaps in steel-aluminum bonding position. In order to avoid gaps in bimetal contact surface, the influence of steel ring thickness on deformation coordination of two metals should be fully considered in cold extrusion of steel-aluminum composite metal gear.

Based on the finite element theory, the stiffness of an insulated carriage is analysed in this paper. Different from the traditional car, the thermal insulation car puts forward higher requirements for the bending stiffness and torsional stiffness under static and full load conditions. Through the finite element stiffness analysis, the stiffness of the whole frame can be preliminarily determined. The results show that under the bending condition, the tail deformation of the carriage is large and the tail stiffness is insufficient. In the follow-up, it is necessary to improve the tail bending stiffness of the carriage through structural optimization.

The usually, softening occurs when metals are annealed, while for some special metals or alloys, the abnormal phenomenon of annealing hardening will occur. By means of X-ray diffraction (XRD), metallographic (OM) observation, transmission electron microscopy (TEM) and hardness test, the microstructure and hardness of 79% cold rolled Al_0.5CrFeCoNiCu high entropy alloy was studied after isothermal annealing for 1 hour at different temperatures, which revealed the cause of annealing induced hardening of the alloy. The results show that the homogenized high-entropy alloy is a face centered cubic (FCC) biphasic structure with close lattice constant. After annealing at 300-750°C, the microhardness of the alloy is higher than that of the cold rolled alloy (399hv); With the increase of annealing temperature, the hardness increased first and then decreased. After annealing at 500 °C for 1 hour, the hardness reached the peak (489hv). XRD phase analysis shows that the alloy will precipitate body centered cubic (BCC) phase when annealed at 500-950°C and precipitate σ phase when annealed at 700-850 °C; In addition, when annealed at 650°C and above, the dislocation recovery speed in FCC phase is accelerated and recrystallization will occur, resulting in rapid softening of the alloy. TEM observation showed that there were L1₂ nano-precipitates with ordered structure in the FCC phase of the matrix. Therefore, the reason for the hardness peak of the alloy annealed at 500°C is the joint action of dislocation strengthening and precipitation strengthening (L1₂ and BCC phases).

The M2052 (Mn-20Cu-5Ni-2Fe, at%) damping alloy specimen was prepared by laser melting deposition (LMD). And we studied the mechanical properties and microstructure of M2052 alloy. Columnar dendrite penetrating multiple cladding layers appeared in the as-deposited sample, and the size of dendrite tends to coarsen with the increase of laser power. Microsegregation and martensitic transformation occurs in the as-deposited M2052 alloy. The tensile strength of samples in different directions under the same process, and in the same direction under different processes is all exceeds 500 MPa. The fracture surfaces exhibit intergranular fracture model. This work shows great potential for fabricating Mn-Cu based damping alloy by LMD technology.

The effects of different Ce contents on the microstructure and hardness of (Ni₂CoFe)_86-xTi₈Al₆Ce_x (x = 0, 0.1, 0.3, 0.5, 0.7, 1.0 molar ratio) high entropy alloys were systematically studied. The results show that the addition of Ce promotes the precipitation of new FCC and BCC phases. The precipitates were promoted by Ce, and the grains and structures were refined by Ce. With the gradual increase of Ce content, the hardness gradually increases. The microhardness (HV) of (Ni₂CoFe)₈₅Ti₈Al₆Ce HEA is 458.6. The increase of precipitate volume fraction and fine grain strengthening are the main reasons for the increase of hardness.

2024 aluminum alloy is an engineering equipment material with broad application prospects, which can be used in space flight and shipbuilding industry. However, the lack of corrosion resistance hinders its further application. The effects of milling and further shot peening processes on the surface integrity of 2024 aluminum alloy were investigated. Electrochemical polarization measurements were performed in 3.5wt% NaCl solution to characterize the corrosion resistance of milling alone surfaces and the further shot-peening process surfaces after milling. Experimental results reveal that the surface residual stress and microhardness of the shot-peened surfaces are much higher than those of the only milling surfaces owing to the severer plastic deformation induced by further shot peening process. While the shot-peened surfaces are roughened with the higher surface roughness. Under the synergic effects of three terms mentioned above, the corrosion potential of shot-peened surfaces is much positive than that of milled ones, meaning the corrosion resistance after shot peening is better. The comparison test gives a way to enhance the corrosion behavior of 2024 aluminum alloy milled surfaces.

We present a fundamentally different approach to process the bimodal Ti-based alloy (Ti-Nb-Fe-Co-Al) by semi-solid sintering stemmed from hypoeutectic reaction, aiming at achieving ultrafine eutectic structure, β-Ti and micron-sized dispersed phase with strengthening effect. As expected, the microstructure of the processed Ti-Nb-Fe-Co-Al alloy contains local ultrafine eutectic structure (β-Ti and TiFe), residual equiaxed β-Ti and micron-sized dispersed phase Ti₂Co. This alloy possesses excellent properties, the yield strength is 1620MPa and large plastic strain is 20%, superior to those of the previous fully eutectic alloy by casting. The novel idea is helpful to fabricate high-performance alloys and metals, which belonging to high temperature alloy systems.

Boron nitride nanosheets have superior chemical and physical properties. However, there are many problems in the preparation of hexagonal boron nitride nanosheets, and an effective exfoliation method is still lacking. To solve this problem, this paper intends to obtain boron nitride nanosheets by ball milling using TpPa from COFs material as a ball milling aid, and to investigate various factors affecting the ball milling effect. The h-BN obtained by using some other polymer materials such as starch and pvp as ball milling aids were compared with the h-BN peeled by using COFs materials as ball milling aids, and the results showed that the peeling effect of using TpPa as ball milling aids was not satisfactory because the structure of COFs materials was too stable. This paper also further conducted ball milling experiments on a variety of dry auxiliaries and compared them according to the ball milling effect The strength, friction, softening point and hardness were analyzed by machine learning. The analysis revealed that these aspects affect the cross-sectional area, thickness and aspect ratio of h-BN nanosheets. To obtain good h-BN nanosheets, the main conclusions of this paper are as follows: For the cross-sectional area of h-BNNS: the bond strength, friction, hardness and softening point of the ball milling agents have a strong influence on it and are positively correlated with it, while the friction and softening point of the ball milling agents are negatively correlated with it. For the thickness of h-BNNS: the bond strength and decomposition point of ball abrasives have influence on it, but not much, while hardness, softening point and contact angle have more influence on it, and hardness and contact angle are positively correlated with it, and softening point is negatively correlated with it. For the aspect ratio of h-BNNS: the hardness, softening point and contact angle of the ball abrasive have a greater effect on it, while the softening point has the greatest effect on it with a positive trend and the hardness and contact angle with a negative trend.

The dynamic characteristics of CNC feed system are determined by the dynamic characteristics of mechanical drive and control parameters. The dynamic characteristics of transmission link are closely related to the mechanical characteristic parameters. The designer must find the matching control parameters by analyzing the law of mechanical characteristic parameters and dynamic characteristics. In this paper, the relationship between inertia ratio, resonant frequency and velocity loop control gain is analyzed by using the established three-inertia system model, and the parameters are input into the system model for simulation. It provides a method for the designers of CNC machine tools to adjust the internal control parameters, which has important theoretical and practical value.

A multi-condition topology optimization research method with weight coefficients is proposed to optimize the topological optimization of solder joints of stainless steel spot welding vehicle. Based on the SIMP variable density method, the compromise planning method, the orthogonal experiment design method, the gray correlation method, the entropy weight method and the analytic hierarchy process are used to introduce the weight coefficients, and objective function of the multi-objective topology optimization of the welding points of the stainless steel spot welding vehicle is established. This method realizes the topology optimization of the stainless steel spot welding vehicle model with the goal of flexibility the minimizing of multiple working conditions. It is concluded that the entropy weight method is more suitable for determining the weight coefficient analysis of objective function of multi-condition topology optimization. The average variation value of the flexibility under the three working conditions is the largest, and the number of solder joints is reduced by 17.8% after optimization. The proposed multi-condition topology optimization research method can be applied to the topology optimization design of railway vehicle structure.

The calibration accuracy of the camera largely affects the accuracy of 3D measurement, so this paper researches on the calibration error of the binocular stereo camera, introduces the imaging model of the camera, conducts the experiment of calibration according to the principle of Zhang Zhengyou's calibration, and responds to the calibration accuracy by the reprojection error, the experimental results show that the calibration meets the requirements and the average error can reach 0.05pixels.

Hub motor is the development direction of new energy vehicles in the future. Usually, the reduction drive hub motor is directly arranged in the narrow rim space, so there are strict restrictions on the volume and weight of its reducer. This paper presents a highly integrated transmission scheme which can improve the working life of the reducer. For the planetary gear reducer integrated by the reduction drive hub motor, a multi-objective optimization function with minimum volume and large coincidence degree is constructed. In terms of constraints, the necessary conditions of planetary gear transmission are fully considered, the gear module meets the requirements of national standards, and the strength conditions of gear transmission. Using genetic optimization algorithm, the optimal solution satisfying the constraints is obtained. The optimization results show that the coincidence degree of the engagement between the sun gear and the planetary gear increases by 67% and the equivalent volume decreases by 31%, which can reduce the volume and reduce the transmission noise at the same time.

To reveal the transient temperature distribution pattern inside the magnetorheological grease (MRG) torsional vibration damper and explore the relationship between the current and the internal temperature of the device, the transient temperature simulation analysis of the MRG device was conducted in this paper. Firstly, a theoretical heat transfer model of MRG torsional vibration damper with dual heat source structural feature was established based on the Bingham constitutive model and the temperature-dependent viscosity characteristic of MRG. Then, the transient temperature field model of the MRG torsional vibration damper was developed by the finite element method, and the temperature field distribution and temperature-time variation characteristics of the MRG torsional vibration damper were analyzed. The simulation results show that the temperature rise of MRG in the working domain is the fastest, and the temperature rise rate slows down after the device works for 5.4s. The simulation results reveal the internal temperature distribution and temperature rise characteristics of the torsional vibration damper, which provides a theoretical basis for the structural optimization and control strategy design of MRG torsional vibration damper considering temperature factor.

According to the motion characteristics of Axial-Symmetric Vectoring Exhaust Nozzle (AVEN), its motion process is divided into the convergence deflection of the adjusting piece of the A8 sub-mechanism and the expansion deflection of the adjusting piece of the A9 sub-mechanism. Taking the A9 sub-mechanism as an example, proposing a method based on Solidworks-Abaqus-Adams multi-software platform to establish a rigid-flexible coupled parametric model and run the motion simulation model to analyze the influence of different factors on the motion accuracy of the mechanism. Basing on the Monte Carlo sampling algorithm to design a program of automatic sampling solution that is separated from Adams platform. Under the condition of meeting certain accuracy requirements, the degree of automation in the sampling process is greatly improved. Finally, the probability distribution of the performance parameters of the A9 mechanism is obtained, and its reliability is calculated. The research results show that when considering various influencing factors, the motion accuracy of the mechanism will have corresponding deviations, which will have a certain impact on the reliability of the mechanism.

In order to obtain the theoretical model of a gun buffer system, the dynamic vibration characteristics of the buffer system were studied by force hammer experiments, and the vibration acceleration response curves of the buffer system after being excited by the impact load were obtained. The acquired signals were processed by noise reduction, detrending, data smoothing and frequency domain integration, and the second-order free vibration model was used to identify the stiffness, damping and other parameters of the system, and compared with the experimental results. The deviation between the calculated results of the identification model and the experimental results is less than 4%, which compared with the general direct identification method, the error is reduced by about 10%. This method can provide a simple and fast technical way for the accurate identification of vibration system models.

According to the requirements of high resolution and compact space of a rotational-double-prism system, combined with its practical application characteristics of small load and low speed, an offset twist-roller frictional transmission mechanism is proposed. Compared with the clearance elimination gear transmission mechanism, it has the advantages of high output resolution, adjustable reduction ratio, simple structure and low cost. The influence of twist angle on the output characteristics of offset twist-roller frictional transmission mechanism is studied by experiment. The results show that the larger the twist angle, the smaller the driving torque of the driven wheel, the larger the transmission ratio of the mechanism, the larger the fluctuation range of output angular velocity and transmission ratio, and the more unstable the transmission. The transmission ratio of the mechanism in stable transmission is about 30, which is much higher than that in single-stage cylindrical gear drive. The output angular resolution of the mechanism is better than 0.005°, meeting the system requirements. Through the above analysis, it lays a foundation for the application of offset twist-roller frictional transmission mechanism in rotational double prisms system.

In order to verify the rationality of the designed L-type electric luggage conveyor vehicle frame structure, this paper imports the frame structure of the designed L-type conveyor vehicle into ANSYS Workbench software, conducts modal analysis, and evaluates the performance of the frame by analyzing the inherent frequency and vibration pattern, then uses Matlab to build the simulation model of the airfield pavement, calculates the power spectrum density, and the dynamic response and stress solution of the conveyor vehicle under specific operating conditions, and conducts random vibration The dynamic response and stress solution of the frame under the specific operating conditions are obtained. The results show that the frame of the L-type electric luggage conveyor is less excited by the road surface during the driving process, which will not cause large damage to the structure and is reasonably designed in terms of vibration characteristics.

Based on the existing research on the conjugate curve gear, the meshing equation of the shaving process is deduced according to the gear meshing principle and the working principle of the disc shaving cutter, so as to obtain the tooth surface equation of the shaving cutter corresponding to the conjugate curve gear, which provides a theoretical basis for the design of the shaving cutter of the conjugate curve gear.

As a result of different fatigue characteristics influenced by intricate microstructures, comparing with fatigue crack growth rate in long fatigue crack region, the growth in the short one is more complex to be fitted with fewer parameters. There have been more restrictions for traditional models in describing the nonlinearity between the fatigue crack growth rate and stress intensity factor range in short crack regime. Due to their outstanding ability in prediction with high accuracy and in description of nonlinearity with satisfactory flexibility, machine learning approaches have been payed more attention. The machine learning models have been the better choices to deal with the limitation in fatigue-related problems which traditional solutions cannot overcome. In this paper, two machine learning algorithms: k-nearest neighbour algorithm (KNN) and random forest (RF) are implemented to predict the short fatigue crack growth rate for 2024-T3 and LC9cs aluminium alloys. The testing outcomes of these applied machine learning algorithms are compared to evaluate their prediction abilities. The final results reveal that the values of Pearson correlation coefficient R² of the KNN are generally higher than that of another method for each material. Each of them has an excellent performance in accuracy and effectiveness, and all of them have excellent extrapolation capabilities to predict the nonlinearity.

With the increasing demand for high precision micro parts in machining field, the development of micro hole drilling technology, especially the finite element simulation technology is rapidly promoted. However, there are many limitations in the simulation of micro-drilling, such as element size, computational efficiency, chip forming, etc. In the present work, a finite element software, Abaqus has been used to simulate the thermal-mechanical coupling micro-drilling process of titanium alloy material, and the key technologies, such as twist bit modeling, material constitutive model, chip separation criterion and element division, were investigated. Through simulation, it was found that with the increase of rotational speed and the decrease of feed speed, chip shape gradually fragmented, in addition, thrust force and torque diminished. Since chip shape, thrust force and torque are important factors affecting drilling quality and tool life, the work could offer important guiding significance for cutting parameter optimization.

In this paper, W-Mo-Y co infiltration were carried out on the surface of 45 steel wedge components by plasma solid-state surface metallurgy technology. The phase, hardness, friction and wear properties before and after W-Mo co infiltration and W-Mo-Y co infiltration were systematically studied. The diffusion kinetics such as diffusion coefficient and diffusion activation energy were calculated by Fick's second diffusion law, and the effect of Y on the diffusion of W and Mo atoms in the infiltrated layer was obtained. It is found that the addition of rare earth Y element increases the diffusion coefficient of W and Mo atoms and reduces the diffusion activation energy, which has a certain catalytic effect. And the W-Mo-Y co infiltration significantly improves the surface hardness and wears resistance of the parts and prolongs the service life of the parts.

In view of the shortcomings of the traditional overflow pressure regulating and throttling speed regulation system, such as large energy loss, high oil temperature and large reversing impact, a servo two-way pump control system for asymmetric hydraulic cylinder is proposed based on Siemens S120. TIA Portal And Starter software are used for the design of hardware configuration and program debugging. SimulationX is used to simulate the stroke process of the hydraulic cylinder, at the same time, experimental verification was carried out, which provides a new idea for the low energy consumption design of hydraulic cylinder servo control system, and has important practical significance.

It is of great practical value to complete the low-pressure casting of aluminum alloy impeller in the current development of low-pressure casting process. In the research, it is necessary to focus on factory realization and use low-pressure casting to produce aluminum alloy impellers, so that impeller castings with compact structure and meeting performance requirements can be obtained. Compared with other casting methods, low-pressure casting itself, as a precision casting method, can be cast on the metal solution with lower pressure in the application process. The castings can be filled and solidified under certain pressure, and the castings with compact structure can be obtained. In the research, Pro / Engineer is used to design the low-pressure casting mold for aluminum alloy impeller, and MAGMASOFT is used to carry out the filling and solidification process of aluminum alloy impeller. Through numerical simulation, we can accurately predict the defects of impeller castings, and optimize the mold scheme and pressure-time parameters according to the prediction results.

In control systems, external analog signals need to be converted into digital signals. When sampling external input analog signals, such as voltage or current, it is necessary to process the small analog signal amplification or large signal reduction to the digital signal that can be sampled normally by the ADC; at the same time, the complexity of the external environment will affect the accuracy of sampling, and the input and output isolation processing needs to be carried out. Therefore, in order to solve the problem of low sampling accuracy of analog signal ADC in complex environment, this paper proposes an analog signal isolation conditioning circuit, which can filter out the high-frequency noise in the input signal without affecting the rapid sampling of the ADC, and use two-stage operation amplification to perform gain and zero compensation processing, so that the conditioned signal has high accuracy, good linearity, and strong anti-interference ability, which meets the design requirements. Through functional and stress tests, the functional correctness and performance stability of the analog signal isolation conditioning circuit proposed in this paper are verified.

In this paper, ANSYS Workbench software is used to establish the brake caliper finite element model, finite element analysis of the model. Under the premise of satisfying the strength, stiffness and stability of the caliper model, Workbench DesignXplorer module was used to optimize the caliper parts' dimensions, and a two-level response surface model was constructed based on OSF algorithm. The caliper mass was taken as the main output parameter, and the lightweight design was carried out through MOGA multi-objective optimization. In terms of material lightweight, new vermicular cast iron was selected to replace QT450, QT600 and Q235 materials. After lightweight design, the yield strength and tension and compression strength of calipers were satisfied, and the mass was reduced by 15.4%

A novel type of interdigital sensor that has been introduced in this paper can non-destructively detect the thickness of insulating materials, e.g. tire. The sensor was manufactured by jet printing technology with high efficiency. The function of the developed sensor is based on the hindering effect on the transmission of electromagnetic signals. The thickness of the insulating materials can be therefore obtained by monitoring the degree of signal reflection through transmission. For optimization, sensors made with three recipes have been experimentally tested. It is concluded that the sensor with double layers' structure possesses the optimal performances. Practically, the application of the developed sensor in detecting the wear of tire tread has been carried out.

SpaceClaim was used to parameterize the main dimensions of 6.50R16 trailer hub model. The sensitivity diagram of hub parameters was obtained based on Central Composite Design (CCD) algorithm, and the stress area of hub was screened out. Using transient mechanical fatigue analysis was carried out on the wheel under the condition of impact load on the S-N fatigue curve obtained hub fatigue failure area, through Admass STEP function wheel movement geometry curve under impact load is determined, according to the result of wheel hub parameter sensitive figure, fatigue analysis and topology wheel movement curve area under impact load, The shape of the hub model was optimized based on topology optimization, and the new hub model was constructed by SpaceClaim geometric post-processing. After topology optimization, the hub quality is reduced to 16%

In order to meet the requirements of heavy off-road vehicles for long-stroke elastic elements, a new type of double-chamber hydro-pneumatic spring was innovatively designed. According to the structure and working characteristics, the mathematical models of the spring under two working conditions are established, and its stiffness characteristics are analyzed. The force and displacement data of the spring at different frequencies were obtained by rig test. The static friction, damping and elastic force of the spring are separated. Based on the data of elastic force and displacement, the polytropic exponent of hydro-pneumatic spring under different working conditions is identified by curve fitting. The structure and theoretical model of double-chamber hydro-pneumatic spring designed in this paper provide support for the application of hydro-pneumatic spring in long-stroke off-road vehicle.

Because electricity is so difficult to store, the electric power department needs to store enough power in advance, whether customers use it or not. To lower the cost of the electric power department in this aspect, it is essential to realize high-precision power load forecasting. The Elman neural network (ElmanNN) prediction model based on the improved Particle Swarm Optimization (IPSO) algorithm is constructed. The Particle Swarm Optimization (PSO) algorithm is brought in, and the learning factor of the algorithm is optimized for the limitation that the PSO algorithm can easily obtain the local optimal solution. Finally, the improved algorithm is applied to the ElmanNN. The improved ElmanNN solves the problems of slow training speed and is effortless to obtain the local minimum. Finally, simulation experiments verify that the ElmanNN model based on the improved PSO algorithm has a smaller prediction error in power load prediction.

Contact state between work roll and backup roll has significant influnce on surface fatigue and strip steel shape. In this work, the contact behaviours between work roll and backup roll of a hot strip mill were investigated. The contact stress distributions along the axial and radial direction were calculated. The effect of uneven contact stress distribution on strip steel profile was analysed. The risk of roll fatigue caused by contact stress concentration was pointed out. In order to improve the contact stress distribution, a design method of the backup roll profile was proposed. Both finite element calculation and industrial test have been carried out and showed that the new profile was excellent in reducing the peaks of the contact stress, homogenizing backup roll wear and improving strip profile.

A 1600kN closed double point press is used for the punching process of U-shaped longitudinal beam and more than 10 independent die frames are arranged. Different holes require different punching forces, and multi-station punching will cause eccentric loads, while preload and off-centre load are important factors affecting the precision of the combined frame of closed press. In this paper, a 1600kN press combined frame is designed based on the U-shaped longitudinal beam punching process and the three dimensional model of 1600kN press frame is established by Solidworks. The finite element analysis of preload, symmetrical load and off-centre load was carried out by Ansys Workbench. The deformation of upper beam in Z direction and the relationship between eccentric load factor i and the maximum deformation difference △h can be obtained, which has important application value to improve the manufacturing accuracy of this type of press.

In order to fulfill the requirement that the electric linear load simulator needs to improve the loading accuracy by the compensation method based on the friction model in the active loading situation with small load, considering the influence of load on coulomb friction and maximum static friction, an improved LuGre friction model with load is proposed. At the same time, since the friction effect is highly nonlinear and determined by numerous parameters, the differential evolution algorithm is utilized to identify the static and dynamic parameters of the model in two steps offline. Finally, under the sinusoidal signal for force command, the experimental test results verify that the improved LuGre model with identified parameters can accurately describe the friction characteristics of the electric linear load simulator.

In this paper, the parallel shaft fine-pitch involute plastic-powder metallurgy engagement spur gear pair produced according to the recommended backlash value of DIN standard is taken as research object. The coupling between the backlash and the bearing radial clearance is considered. And the expression of the dynamic backlash is derived. A three-degree-of-freedom two-state dynamic mathematical model of the parallel shaft gear transmission system is established. The time-domain curves of gear displacement, velocity, engagement force and dynamic backlash are obtained. The results of mathematical model show that a larger backlash range than DIN standard recommended is more conducive to smooth transmission.

A master-slave synchronization control strategy based on RBF network adaptive sliding mode control is proposed to solve the problem of lack of effective control strategy and control accuracy in the process of synchronous motion of three horizontal cylinders of multi-directional die forging hydraulic press in VL ball cage forming process. According to the high-order nonlinear mathematical model of the single-cylinder electro-hydraulic servo system, the RBF network adaptive sliding mode controller is designed. The joint simulation model is established by using AMEsim and MATLAB to solve the tracking accuracy and synchronous control accuracy of the system, and the control effect is verified by comparing with the conventional PID control. The simulation results show that the RBF network adaptive sliding mode controller has strong robustness, and the three horizontal cylinder displacement synchronization controllers of the multi-directional die forging press designed in this paper have good synchronization performance.

Micro reducer is widely used, but its mechanical efficiency is not high. Selecting metal materials and engineering plastics to form the motion pair can reduce friction and wear. Selecting new materials in the design of the reducer and adopting new molding technologies can improve the precision of gear transmission and reduce noise and vibration. For a reducer with a large transmission ratio and many transmission stages, rational allocation of the transmission ratios at all levels in the structural design can improve the efficiency of the reducer. Different planetary gear structural designs will also affect the mechanical efficiency, and the structural design is optimized so that the reducer can better take into account the relationship between load and mechanical efficiency.

STATCOM, a star cascade H bridge, usually uses zero-sequence voltage injection to achieve inter-phase DC voltage balance. Different from negative sequence current injection, the phase-to-phase DC voltage balance control based on zero sequence voltage injection does not generate zero sequence current in three-phase and three-wire systems, which is beneficial to the power quality of the system. In the traditional control algorithm, the zero sequence voltage is calculated by the unbalanced active power and current. The control algorithm contains a large number of complex operations and matrix operations, which need to consume a lot of controller resources and is not conducive to system design and expansion. Moreover, in order to improve the dynamic performance under voltage imbalance, the positive and negative sequence separation is introduced into the feedforward control to increase the complexity of the control algorithm. In order to simplify the control algorithm, a PI regulator is proposed to linearly adjust the DC component of zero sequence voltage in DQ coordinate system. At the same time, through theoretical analysis, it is found that the zero-sequence voltage in feedforward control is equal to the zero-sequence voltage in power grid, so the positive and negative sequence separation can be removed, further simplifying the algorithm.

Aiming at the difficulty of fine modeling of dual-motor precision transmission mechanism, the modeling of friction and clearance of the system is studied. Firstly, the structure of the double-motor precision transmission mechanism is introduced, the system is simplified to a three-mass system, and a linear model of the system is established. On this basis, the improved stribeck model is used to describe the friction nonlinearity inside the two-way transmission chain and the large ring gear, and the dead zone model is used to describe the gap nonlinearity between the pinion and the large ring gear, thus forming a complete dual-motor precision transmission mechanism. kinetic model. An experimental device was built, and different excitation signals were used to verify the accuracy of the model. The experimental results show that the Pearson correlation coefficient between the established dynamic model and the actual system is >99% under various excitation signals, which shows the accuracy of the modeling method.

Aiming at the problem of motion accuracy caused by dispersive dispersion in the design of the aero-engine rear variable area bypass injector, a multi-body dynamics model mapping dimension tolerance, part flexibility, and collision contact is established based on multi-body dynamics theory and ADAMS. The simulation results are verified with the theoretical solution, which is calculated in MATLAB to ensure the correctness of the simulation's results. The effect of key design variables on the motion accuracy of the mechanism is analyzed by the parametric module. The reliability calculation method is studied based on the improved Latin hypercube Monte Carlo method mapping the dimension dispersion. The method provides the relevant basis for the structural design of the RVABI.

Bearingless motorized spindle is a new type of motorized spindle composed of bearingless motor and motorized spindle. With the increasing speed, the spindle will produce obvious gyro effect and vibration interference, so it is of practical significance to study the vibration control of bearingless motorized spindle. In this paper, the principle of minimum rotor vibration displacement is introduced, and a compensation controller based on adaptive feedback is designed and verified by simulation.

At present, the research hotspot of switched reluctance motor is to realize the accurate control of motor without position sensor. Among many control methods, the phase inductance slope method is concerned by researchers because it does not need to add additional power supply circuit, and does not need to calculate the flux linkage and inductance curve in advance. Aiming at the defect that the phase inductance slope algorithm can not advance the opening angle and the position signal error is easy to appear near the opening angle, this paper makes an improvement and verifies the experiment.

A Multi-channel power input automatic switching system used for mobile vehicle equipment based on power quality analysis is proposed in this paper. The basic measurement principle of power quality analysis is introduced first, based on this principle, a hardware implementation of the power quality analysis unit is fulfilled, including function diagram, measurement sampling circuit, and communication interface circuit. A communication interface protocol is designed based on CAN bus used for interaction between the multi-channels of power supply input. Based on the power quality analysis unit, the multi-channel power input automatic switching system is proposed driven by the priority of input channel determined by sharing the data of the power quality between the multi-channel power supplies.

This paper presents an analytical solution to inverse kinematics problem of a 6-DOF robot arm based on geometric method. The solution only utilizes relations between vectors in frames attached in the robot arm. Experiments with the solution are conducted to test the approach and results show that the correctness and accuracy of the solution are verified.

There are more and more traffic accidents between cars and electric two wheeled vehicles. As a vulnerable participant in traffic, it is of great significance to study the head biomechanical injury of electric two wheeled vehicle cyclists. In order to study the head injury of cyclists, by optimizing the tissue material properties and material parameters of the head finite element model, a refined head finite element model is established and verified by Nahum cadaver experiment; Based on the real traffic accident of vehicle electric two wheeled vehicle collision, a multi rigid body model of vehicle electric two wheeled vehicle is established for vehicles, electric two wheeled vehicles and cyclists, and the reliability of the collision model is verified; The head finite element model is used to analyze the changes of equivalent stress. The results show that the equivalent stress of brain tissue is gradually transmitted from both sides of brain tissue to the cerebellar region at the back of brain, and finally concentrated in cerebellum.

As the exploration of marine resources continues to deepen, the Unmanned Underwater Vehicles (UUV) have gradually become the focus of industries such as military, fishery, seabed prospecting and marine platform monitoring. At present, the identification technology of the dynamic model parameters of the UUV is not mature yet, and the robustness is poor. In order to solve the problem that the identification algorithm is susceptible to underwater noise when the robot is navigating underwater, this paper integrates the Huber loss function into the recursive least square method, and proposes a robust identification algorithm to improve the control of the underwater robot Accuracy. Finally, the dynamic model of the underwater vehicle is simulated in Simulink to obtain a reasonable input signal, and then this algorithm is used to simulate and identify the model under Gaussian noise with 'outliers'. The simulation results show that the algorithm has strong robustness while ensuring the identification accuracy.

Starting from the current multifunctional integration and architecture design development status of the flight control system for the mainstream civil aircraft, this paper proposes the system design concepts of "In and Out as a Whole", "Direct Connection and Transmission", and "Same Sources and Routes" for the external sensors application sources of the fight control system. External application sources are air data, inertial Reference data and angle of attack sensors in this paper, specifically. This paper analyzes and compares the functional residence and separation processing of external application sources for fly-by-wire flight control system. In addition, it demonstrates the correctness of this design concept and its practical engineering value, systematically. This work has provided a significant reference for future civil aircraft design.

Precise cable drive is a light, concise and efficient spatial friction flexible transmission mode, which has the characteristics of flexible layout, lightweight and miniaturization. It is a good choice for Acquiring tracking and pointing applications (ATPs). But the cable drive mechanism (CDM) is easy to cause large-scale speed oscillation in the process of performing tasks as cable compliance. This paper focused on the mechanical resonance in a practical full-closed loop positioning control system. A dynamic model with the electro-mechanical and rigid-flexible coupling characteristics is proposed, which is capable to analyze the global influence factors on speed oscillation. The parametric sensitivities have been conducted to investigate the effects of design parameters on mechanical resonance.