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In this work, the microstructure and properties of the first-Republic Czechoslovak circulation coins were studied. The variety of the coins at that time was shown. Significant differences in microstructure in the direction of forming and in the normal direction to the surface direction have been confirmed. For some coins, visible features of recrystallization were shown, which suggests the coinage at higher temperatures. The chemical composition of coin alloys was also studied. In most cases, it was consistent with the declared chemical composition by mint. Significant differences in the hardness of the coins were found, which confirmed the different experience of numismatics with the abrasive resistance and the preservation of different coins. The quality of the design and the material composition of the coins confirm the long-standing experience with coinage in the Czech lands, despite the fact that, after the Austro-Hungarian Empire, the mining industry was struggling with big problems (eg stolen raking machines, lack of Czech mining experts). The first-Republic circulation coins represent the best in the history of the Czech and Czechoslovak coinage industry.

In this study, the microstructure of surface layers with varying roughness (Ra parameters) was analyzed using scanning electron microscopy (SEM) to optimize tribological properties in engineering design. SEM revealed key microstructural features – sharp and mild protrusions, pitting, microcracks and contaminants – that were not available in traditional profilometry. Reducing the Ra value improved surface uniformity by reducing irregularities and defect lengths, which had a positive effect on tribological properties and surface durability. However, defects were still present even at Ra < 1.25 μm, indicating the "Law of Microstructural Roughness," which emphasizes the inevitability of surface irregularities despite minimizing roughness. The integration of SEM results with profilometric methods enabled comprehensive identification and assessment of defects, combining microstructure with tribological properties. Results suggest that controlled roughness is key in combining materials and optimizing functional surfaces, particularly in the aerospace, biomedical and automotive industries, where reliability under demanding operating conditions is a priority.

With the increase of hydro generators capacity and unit size, the requirement of lightweight is prominent. Taking a mixed-flow hydro generator as the research objects, the strength, the stiffness and the dynamic characteristics of upper bracket, stator frame, lower bracket and head cover have been simulated and analyzed by means of establishing their finite element models. Based on sizing optimization design method, plate thicknesses of the main parts were selected as the design variables, and strength and stiffness were taken as the constraint conditions to optimize them with the minimum mass as the objective function. Through lightweight optimization design, the maximum normal stress and maximum displacement of the optimized main parts are within the allowable value range, modal analysis shows that their dynamic characteristics meet the requirements. The lightweight optimization design reduced the weight of hydro generator by 3457kg in total. Optimization effect evaluation under full load operation and site test between the original and improved hydro generator set show that the dynamic characteristics are improved and the performances meet the design requirements.

In response to the problems of insufficient strength and stiffness, as well as large weight in traditional car frames, this article takes titanium alloy frames as the research object. Based on the analysis of static and dynamic characteristics, a lightweight design is carried out to meet the design requirements. Firstly, static analysis was conducted on the frame structure under four different working conditions using the finite element analysis method to study its stress distribution and deformation under different loads and road conditions. Study the natural frequency and vibration mode of the frame through modal analysis, providing a basis for subsequent optimization design. Through harmonic response analysis, explore the changes in the amplitude and frequency of the frame during use. On this basis, topology optimization and lightweight design are carried out on the frame structure to reduce the weight of the frame and improve its strength and stiffness. Finally, validate and compare the optimized frame to explore the feasibility and superiority of the optimization plan. The research results show that the optimized frame weight has been reduced by 13.76%, the maximum stress has been reduced by 5.19%, and the maximum deformation has been reduced by 0.37%, effectively reducing the frame mass. This provides a way of thinking about the static and dynamic characteristics analysis and topology optimization design of automotive frames.

The paper is a further step in ongoing research on the incorporation of the proposed bulk material rotary valve assembly into an existing production line serving the food industry in bagging milk powder. The main objective of the present paper is the strength static analysis of the previously presented structural design of the trolley and attachment of the frame structure as a track for the travel. Moreover, analytical engineering calculations whose results provide boundary conditions for the numerical strength design of the assembly of the rotary valve for transporting of bulk materials are included in the paper. The pro-posed mechanism allows precise manipulation of the rotary valve, especially at the time when it is nec-essary to clean the pipe connected to the rotary valve. Such manipulation is currently actual because of increasing the safety of maintenance of machines and equipment as well as because of reducing the physical burden of maintenance workers. The results of the analyses demonstrate the suitability of the design and provide a basis for further research in this area. The results discovered will be implemented in the form of additional boundary conditions in the numerical analyses of the frame itself carrying the whole travel of the trolley with the rotary valve (the frame forms the track for the trolley travel). The aim of the research is to reach a condition where the entire structure is safe for the operator during mainte-nance as well as for its surroundings during normal operation.

The article describes the creation of a mathematical 3D model of the original hovercraft structure, which will be further used for research into modifying the shapes and materials of the structure to ensure better driving conditions. Proposals for new materials for individual parts of the hovercraft structure will be addressed in order to reduce the weight of the hovercraft and thereby ensure a higher possible speed of movement, reduce fuel consumption and ensure the necessary mechanical properties of individual segments. The mathematical model of the simplified hovercraft model was created in the Cradle and Adams simulation programs. The paper is presented by analyzing the hovercraft properties in order to obtain sets of advantages and disadvantages of the hovercraft. The following is a description of the creation of a geometric 3D model of the hovercraft, which is built using Autodesk Inventor. The article further describes the transformation of the 3D model into a simulation model that can be used for co-simulation of movement in the Adams and Cradle computer simulation systems. The simulations will be the first step towards modifying the structure of a real rescue UAV prototype with improved maneuverability, stability and the ability to traverse terrain with surfaces unsuitable for hovering.

During design process materials and their shapes selection is usually performed unsystematically, selection is mostly based on previous experience, although this is the most influencing part during mechanical design. This paper is devoted to the application of the material-shape factors and indexes to the standard bicycle frame. Paper to show the method with material-shape factors and indexes and how to use it for a simply and fast redesign for a different material and shapes. The whole method is descripted in detail for two examples and the results are verified by FEM analysis.

Fused Deposition Modeling (FDM) is one of the widely used technologies of additive manufacturing. The concern over the surface quality and dimensional accuracy is getting increased among the research community. The design of the experimental methodology is based on the analysis of variance (ANOVA) of fractional factorial design. This analysis was used to study the effect of layer thickness, extrusion temperature, speed of deposition, and fill density on dimensional accuracy and surface roughness of the model developed by FDM. Polylactic Acid (PLA) material has been selected in this work as it is inexpensive, easy to print, and biodegradable. The results showed that layer thickness is an effective factor in determining surface roughness. Fill density (X and Z dimensions), layer thickness (Y dimension), and speed of deposition (Z dimension) are significant factors for dimensional accuracy. Regarding surface roughness, curvature was found to be significant; however, the minimum optimization point was not reached. Thus, more experiments are required to be carried out to get the minimum point. For dimensional accuracy optimization, the dimensions along X, Y, and Z were realized to be more accurate at lower levels of every factor except for fill density (D), which was optimized

Car manufacturers are constantly looking for new options to make the vehicle more attractive to the cus-tomer. In terms of design, this is usually done in the middle of a model's life cycle, when a so-called facelift of a production model is carried out. This involves small changes to the shape of the bodywork to improve the design of the vehicle until it is time for a new model range. This paper discusses a case study that focuses on the modification of the rear body components of a ŠKODA Superb III in Combi version. The aim of the study is to assess how the proposed modifications will affect the aerodynamics of the vehicle. The most sig-nificant changes concern the rear spoiler and finlets. The aerodynamic properties are assessed based on CFD simulations that are performed for a series production and a modified variant of the vehicle, and the results of which are compared and discussed.

This study focuses on addressing the challenges faced by individuals with physical disabilities, particu-larly lower body impairments, by developing a stump socket using Reverse Engineering (RE), 3D Printing, and QFD. The integration of these three methods is something new in product design devel-opment, especially prosthetic products. The research adopted a three-step methodology: 3D scanning the stump, obtaining precise measurements, and fabricating a stump socket using fused deposition modeling (FDM) technology. QFD will produce technical requirements (TR) derived from consumer needs and brainstorming with prosthetists. TR will be the basis for developing the socket design in the 3D Scanning phase. The scanning process utilized Polycam, and the 3D models were refined with Meshmixer. The socket was fabricated using PLA+ material to ensure cost efficiency and customiza-bility. Experimental results demonstrated the accuracy and feasibility of the designed prosthetic sock-et, with a layer thickness of 0.2 mm and printing temperatures up to 215°C. The study highlights the potential of RE and 3D Printing to address the unique anthropometric variations of Indonesian users, overcome the limitations of conventional crutches, and reduce production costs compared to imported prostheses. This approach demonstrates a scalable and innovative solution to improve accessibility and quality of life for individuals with physical disabilities while contributing to economic inclusivity.

Mill-turn center is an advanced CNC machine tool. This paper presents a novel approach to the conceptual design of a mill-turn center. Firstly, the feature model of a mill-turn center is created based on a RW (representative workpiece) in a Top-down way. After that, two concurrent works are studied: the verification model of the machine tool is setup by transforming its finished feature model; the NC programming is done with the help of the technology of CAM (computer-aided manufacturing). Thirdly, the production verifying of the mill-turn center is fulfilled in the NVMS (NC verification manufacturing system). Lastly, the optimum structure dimension of two functional subassemblies and the correct layout of the machine tool can be confirmed with the modification and feedback. This is a universal method and can be used by the designer of CNC machine tool to promote their job target of quality, efficiency and cost.

An agricultural tractor equipped with appropriately rated guards can often replace specialized forestry machinery. Currently, few authorized dealers on the Polish market offer tractors adapted to harsh forest conditions, so this work involved designing a tubular guard for the Kubota M135GX-VI agricul-tural tractor. The aim of this work was to develop a conceptual design for a tubular guard, together with a strength analysis based on FOPS procedures, dedicated to the KUBOTA M135GX-IV agricul-tural tractor. To properly design the tubular guard, applicable standards and regulations regarding the construction of cabs and tubular guards for agricultural and forestry machinery were first analyzed. Subsequently, the available solutions were analyzed and two original concepts were developed. These concepts were evaluated based on the adopted criteria, selecting the variant with the highest score. Furthermore, the most advantageous variant was subjected to a strength analysis using the finite el-ement method (FEM) in accordance with the FOPS procedure. The test results showed that all nodes included in the developed concept met the strength requirements.

The fatigue assessment of a Class 300 valve body with a bore diameter of 450 mm under vari-ous pressures is discussed using Section VIII, Division 2 of the ASME BPVC. Finite element analysis (FEA) results are compared to fatigue test results, and correlations are obtained. The material used for the valve is A216 WCB, which is widely used for making API ball valves. Elastic stress analysis was used to study the influence of various parameters on the results. This method is widely accepted and is used for static components. The body and flange de-signs were performed in accordance with ASME and API standards. Various pressure loads were applied to the inner surface of the valve body, ranging from 4 MPa to 6 MPa. The defor-mation, equivalent stress and stress intensity over the critical areas were analyzed using AN-SYS Workbench. As the pressure increases, the maximum compressive stress over the valve body surface also increases. However, the design of the valve for a pressure of 5.1 MPa (for a Class 300 valve) remained within the safe limit. Increasing the pressure beyond 5.1 MPa also indicates a safe design; the valve can withstand pressure up to 6 MPa (beyond the design pres-sure).

Passive vibration isolator with lower natural frequency has always been a challenge due to structural integrity issues. This study presents the use of RSM statistical tool to analyze and optimize the mechan-ical responses of BCC lattice structure for structural integrity in a passive vibration isolator application. The optimization was done to obtain low stiffness for low natural frequency but high yield stress for optimum load-bearing capability with unit cell size and strut diameter design parameters tweak. From the results, the significance and contribution of each design parameter on each mechanical response through compression test can be understood. Results indicated changes in strut diameter produced lin-ear growth while changes in the unit cell size produced inverse exponential responses. From optimiza-tion, a combination of 3.9 mm strut diameter with 10 mm unit cell size produced the optimum result. Therefore, it was demonstrated that RSM can provide statistical importance and contribution between input factors and their influence on each mechanical response with minimal test and cost.

Although important improvements of prosthetic sockets has been implemented another investigation has been done also by solving problems with inadequate stump heating and from that resulting excessive sweating of limb. This phenomenon is further associated with leg volume changes. Therefore for realization of this research the model of prosthetic limb was created with socket that further addresses these issues of artificial limb. Throw the application of holes and tightening bells the pressure to remaining stump decreased and at the same time the heating of limb is lower. These results indicate that the implementation of these design modification will improve the comfort and fit of prosthetic devices in future.

With the rising demand for efficient, lightweight support structures in high-energy physics experiments, advanced manufacturing techniques and material optimization are key to achieving high-performance designs. This study focuses on the application of generative design and topological optimization in the development of support structures for the FCC muon spectrometer. By leveraging these methods, we maximized material efficiency and minimized weight while ensuring structural integrity and meeting strict design constraints, including non-magnetic properties, minimal deformation, and high precision. A detailed evaluation was conducted with respect to manufacturing techniques that balance perfor-mance with cost-effectiveness, resulting in multiple design iterations of optimized truss configurations. This approach demonstrates the potential of modern manufacturing technologies in enhancing the structural and economic viability of components for large-scale scientific equipment.

This paper presents a new computer-aided method for modular-fixture design, in which the key point is building the fixture on the concept of NC Manufacturing System (NMS). In this paper, an approach of creation for a NMS is proposed, first to extract or setup the feature model of worktable of NC machine tool in any CAD system. Base on the worktable, the algorithm of computer-aided modular fixture design (CMFD) is then presented; the Post-NC verification to check the performance of modular fixture in NC machining is introduced at the last section of the paper. This method could help engineers to develop and employ an error-free modular fixture during the complex NC-manufacturing production.

Taking a brake drum as the research object, the dynamic characteristics analysis and optimization designare carried out by using the finite element method.In order to increase the stiffness without increasing weight of brake drum, the main design parameters were tested by Box-Behnken experiment design. The three-dimensional model of brake drum was established by using SolidWorks software, then the finite element model of brake drumwasobtainedby imported into ANSYS software and its modal analysis was carried out. On the basis of modal analysis, the three important dimensions of brake drum were defined as input parameters, the drum weight, the first, second and third natural frequencies are defined as output parameters. The response surface model between the input and output parameters was established by using DOE (Design of Experiment). Finally, the input parameters were optimized by multiobjective genetic algorithmand the fivePareto solutionswas obtained. The fifth solution was chosen as the optimal solutionbased on the production technique.The weight of brake drum was not changed obviously after optimization, but the first, second and thirdnatural frequencies were increased by13.07 %, 8.92 % and12.73 %respectively, which provided a new idea for the design and optimization for brake drum.

Lower bracket is an important component in hydro generator. Taking lower bracket as the research object, the strength, the stiffness and the dynamic characteristics of lower bracket have been simulated and analyzed by means of establishing a finite element model. With the two design indexes of maximum normal stress and stiffness as the constraint conditions, aiming at an optimized design with the minimum mass and proposed a lightweight optimization method. The design parameters of the optimized model of hydro generator lower bracket are determined by using the compound form method with optimization iteration. Through lightweight optimization design, the maximum normal stress and maximum displacement of lower bracket are within the allowable value range, modal analysis shows that the dynamic characteristics of the optimized structure also meet the requirements, with the potential of material further utilized. The lightweight optimization design reduced the weight of lower bracket in hydro generator by 790kg and the weight-loss ratio reaches 44.38%, thus achieving the purpose of lightweight. The optimization results are applied in the improvement design of lower bracket and the method is practical and suitable for engineering applications.

This study examines the two-pass hot rolling process of 6061 aluminum alloy wire, focusing on forming load measurement to evaluate process stability and its effects on dimensional accuracy and mechanical property uniformity. Using response surface methodology (RSM), process parameters and forming loads were analyzed to assess their influence on mechanical property distribution and verify the applicability of load measurement in process quality evaluation. A full-factorial finite element simulation was conducted to investigate the effects of pre-forming section reduction rate, material temperature, roll speed, and friction coefficient. Experimental results indicate that forming load measurements effectively capture variations in initial wire temperature and reveal the influence of material velocity and roll speed. Load data also identify the Spike phenomenon caused by improper roll positioning, leading to abnormal load surges and reduced mechanical property uniformity. The strong agreement between experimental forming loads and FEM simulations validates the reliability of the proposed measurement method. This study provides a basis for wire rolling process design and machine learning-based quality prediction, supporting advancements in smart manufacturing applications.

This article deals with the design optimization of the mechanical crank press. These presses have not any signifi-cant development changes in a long time. Mechanical press LDC 250 with nominal force 2.5 MN (250 tons) was considered as an example. This type of press can be used for operations such as bending, drawing or cutting. The topology optimization was used during this research. This papers show advantage of this design method. The op-timized press has lower maximal Von-Mises stress in the structure and the maximal displacement is up to two times lower. The research was focused on the main frame (open frame with shape ?C?) of the press. The resistivity aga-ings vibrations was improved. The weight of the frame was not changed. The CAE tool NX Nastran and the opti-mization tool Frustum were used here. The workflow of the topological optimization is deeply described here. The comparison between the conventional (initial) and optimized design shows new approach to these machines.

The article described a new methodology for testing the torsional resistance of a single-stage gear transmission used in agricultural machinery. The analysis encompassed the entire mechanical system rather than focusing solely on its individual components. The research identified three key ranges of structural resistance. The first range, with twist angles from 0° to 1.85° and torques up to 1050 Nm, was associated with the elimination of structural play and the alignment of contact surfaces. The second range, from 1.85° to 4.76° and torques up to 3450 Nm, confirmed the resilient behavior of the gearbox according to Hooke's law. In this range, the system worked stably and maintained repeatability of parameters. The third range, above 4.76° and 3050 Nm, showed the presence of permanent but local deformations. However, these displacements did not affect the functionality of the system in less demanding applications. The maximum torque of 5500 Nm did not cause macroscopic damage or oil leaks, which proves the high quality of the design and the effectiveness of material optimization. The developed method allows for an accurate determination of the safety factor and a detailed assessment of the strength properties. It can be used to optimize transmissions in various sectors such as agriculture, automotive and aerospace. The results also form the basis for further experiments, including fatigue tests and contact stress analyses. The proposed methodology enhances the predictive accuracy of gearbox durability under various load conditions. These advancements support the development of sustainable and efficient mechanical systems across multiple industries.

To design an engine intake system that complies with FSC racing regulations while achieving enhanced operational stability, this study conducts a comprehensive review of domestic and international research advancements in racing engine intake systems. Through computational fluid dynamics simulations performed in Workbench Fluent, critical structural parameters of the restrictor valve were optimized, resulting in a 12.06% improvement in outlet mass flow rate compared to the baseline design. A three-dimensional parametric model of the racing intake system was developed using Siemens NX platform. Taking the intake plenum chamber as a representative component, this research systematically analyzes the CNC machining process for the mold of the pressure stabilization chamber. The investigation encompasses toolpath generation, cutting simulation verification, and ultimately implements the optimized NC program on machining centers for physical manufacturing. The fabricated mold exhibits high dimensional accuracy and superior surface finish, providing both theoretical guidance and practical manufacturing references for intake system development. This integrated approach combining numerical optimization with advanced manufacturing techniques demonstrates significant potential for performance enhancement in motorsport engineering applications.

The article deals with the basic steps of injection mould design. The goal of the research was the proposition of the mould form so to be achieved the minimum waste and the shortest time of both mould filling and product cooling. Studied mould component is intended to serve as a stopper in the automotive spotlight. The simulations were realized for three designed types of running system and for four versions of cooling system. Due to the design optimization, the pressures, originated inside the cooling system and inside the mould cavity during the injection moulding process, were also investigated. 3D model of the mould was created in Autodesk Inventor Professional software and then solidification of material was simulated in Autodesk Moldflow. On the basis of the best solution, real form was manufactured and placed into injection moulding machine Arburg Allrounder 320 C.

The article deals with the principles of fixtures design and their application at machining of armature DM 100, PN 25/40-RF. It is bulky component that is produced by casting technology. Surfaces near the hole of valve are hard machinable due to weld deposit. Considering elimination of clamping device weaknesses that could originate due to unsuitable design and production, it is advantageous to use a virtual model along with simulation and analysis in CAD/CAM system. Nowadays technologists have strong tools in their hands that increase efficiency of solution not only conventional, but also specific, problems. On the other hand, they have to know to solve some difficulties in their mind, such are, for example, the differences in specifications of coordinate systems used for virtual model in CAD/CAM system and coordinate systems used in real production. The problems can arise in case of cutting tool definition according to the tool-in-hand or tool-in-use systems. Based on theoretical know-how two fixtures were designed for manufacturing of two sets of surfaces that are normal each other, so after inovation manufacturing operations were realized in vertical and in horizontal position of workpiece axes. Using new approach, the production efficiency and production rate have increased twice and no failure product has been made.

In order to improve the crushing effect of the rotor of vertical shaft impact crusher on the particle, the design method of secondary accelerated rotor based on kinematics theory is proposed. And the operation effect of the secondary acceleration type rotor was verified using a combination of computational fluid dynamics and discrete element method (CFD-EDM). First, the kinematics of the particles thrown by the rotor throwing head was analyzed. On this basis, the structure of the secondary acceleration type rotor was designed by comprehensively considering factors such as the motion, friction, and collision recovery coefficient of particles; Then, based on the gas-solid coupling analysis method, a simulation model of the rotor's effect on particle acceleration was established and the reliability of the model was verified; Finally, the CFD-EDM method was used to calculate and analyze the motion process of particles in the crushing chamber, the collision position of particles in the crushing chamber, and the average throwing speed of the rotor. Research results show that roughly 77.6% of the particles in the crushing chamber will collide with the impact plate to achieve secondary acceleration; The average throwing speed of the traditional rotor is 57.14m/s, and the average throwing speed of the designed secondary accelerated rotor is 60.89m/s, which is about 6% higher than the average throwing speed compared with the traditional rotor, and achieves the expected design purpose.

The cab of the big-scale and medium-sized agricultural machinery is not only the main environment of the drivers operate the machine, but also by which the driver interact with the machine. Currently most China's agricultural machinery manufacturers will order the whole cabs for production, but not make them by themselves. Therefore to design the cab models by parametric customization would be better adapt to business needs and reduce the repetitive and mindless calculation and design. The design of cab mainly includes two types of parameters: the driver's ergonomics data and the constraint parameters provided by agricultural machine such as space area, etc.. In addition its shape should match the the whole style of the machine. The paper provides a parametric design procedure of cab's frame based on RhinoScript. Firstly the characteristics of a variety of cabs are analyzed and classified into several typical sorts; then the main ergonomics parameters and constraints of these cabs are extracted; finally the basic framework of the cab can be automatically completed on these data and constraints and a digital model can be generated by the chosen style of the agricultural machine.

An approach to increasing the efficiency of the diamond grinding of hard-working materials is shown. A well-founded choice of characteristics of the diamond-bearing layer of the tool can be made through analyzing the results of 3D modeling of the processes of formation and operation of the diamond-bearing layer and stresses upon it. Diamond wheels formed on porous ceramic binders are investigated and discussed.

This paper presents the design and analysis of a 3-PRS mechanism for positioning cutting heads in CNC machines, addressing limitations of traditional rotary mechanisms such as hose twisting, wear, and limited modularity. Kinematic and dynamic analyses guided actuator selection and confirmed bearing durability. The mechanism achieves a favourable load-to-weight ratio and integrated Z-axis movement, making it suitable for simpler gantry CNC machines. Though programming is complex due to multiaxis synchronization, the modular design supports easy adaptation to different tools. Future research will focus on reducing the eccentric torch offset and refining dimensions to enhance versatility. The mechanism has strong potential in sectors like automotive, aerospace, and construction.

In this paper, the design of a robot is proposed to replace manual labor in completing tasks on vertical planes. The aim is to enhance automation in the workplace and eliminate direct human involvement to ensure personal safety. Firstly, the robot's structure is designed as a five-joint biped with vacuum adsorption capabilities. The forward and inverse kinematics of the robot are analyzed. Secondly, using simulation by ADAMS, five key performance metrics are quantitatively analyzed for both this robot and a Hexapod robot. These metrics include adsorption reliability, external load-bearing capacity, friction coefficient adaptability, obstacle-crossing capacity, and joint torque. Thirdly, the main control chip used for this robot is STM32F407. The circuit system design and physical implementation of the robot are based on this chip. Finally, experiments are conducted to study the actual performance of the robot in vertical cleaning tasks.