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Copyright of Engineering Mechanics / Gongcheng Lixue is the property of Engineering Mechanics Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Ballet is a discipline that combines art and sport in a harmonious way. It is a practice that has high physical and mental demands to achieve the proper body precision. During this activity, numerous muscles, including those in the legs, need to be exercised. Therefore, individuals who have lost part of their lower limb due to amputation face numerous significant challenges when it comes to practicing ballet. Throughout this article, the key aspects that influence the design of a lower limb prosthesis specifically adapted for ballet practice will be analyzed. New materials will be explored with the goal of designing an optimal model that ensures maximum performance and comfort for the users. Additionally, the prosthesis will be customized using 3D-printing technology, and a prototype will be presented. This study will merge biomechanics, ergonomics, and design. Its goal is to find a solution that improves the quality of life for lower limb amputees whose passion is ballet. The aim is to overcome physical and emotional barriers and provide a way to reintegrate amputee dancers into the world of dance. It is important to highlight the novelty of this work: combining different disciplines to provide a solution for individuals who engage in dance as a hobby rather than professionally. The proposed methodology aims to enable users with disabilities to access a personalized, complex, and potentially costly product. [ABSTRACT FROM AUTHOR]

Reducing the vulnerability of a platform, i.e., the risk of being affected by hostile objects, is of paramount importance in the design process of vehicles, especially aircraft. A simple and effective way to decrease vulnerability is to introduce protective structures to intercept and possibly stop threats. However, this type of solution can lead to a significant increase in weight, affecting the performance of the aircraft. For this reason, it is crucial to study possible solutions that allow reducing the vulnerability of the aircraft while containing the increase in structural weight. One possible strategy is to optimize the topology of protective solutions to find the optimal balance between vulnerability and the weight of the added structures. Among the many optimization techniques available in the literature for this purpose, multiobjective genetic algorithms stand out as promising tools. In this context, this work proposes the use of a in-house software for vulnerability calculation to guide the process of topology optimization through multi-objective genetic algorithms, aiming to simultaneously minimize the weight of protective structures and vulnerability. In addition to the use of the in-house software, which itself represents a novelty in the field of topology optimization of structures, the method incorporates a custom mutation function within the genetic algorithm, specifically developed using a graph-based approach to ensure the continuity of the generated structures. The tool developed for this work is capable of generating protections with optimized layouts considering two different types of impacting objects, namely bullets and fragments from detonating objects. The software outputs a set of non-dominated solutions describing different topologies that the user can choose from. [ABSTRACT FROM AUTHOR]

Total hip replacement is one of the most successful orthopedic operations in modern times. Osteolysis of the femur bone results in implant loosening and failure due to improper loading. To reduce induced stress, enhance load transfer, and minimize stress, the use of Ti-6Al-4V alloy in bone implants was investigated. The objective of this study was to perform a three-dimensional finite element analysis (FEA) of the femoral stem to optimize its shape and analyze the developed deformations and stresses under operational loads. In addition, the challenges associated with the manufacturing optimization of the femoral stem using large strain-based finite element modeling were addressed. The numerical findings showed that the optimized femoral stem using Ti-6Al-4V alloy under the normal daily activities of a person presented a strains distribution that promote uniform load transfer from the proximal to the distal area, and provided a mass reduction of 26%. The stress distribution was found to range from 700 to 0.2 MPa in the critical neck area of the implant. The developed computational tool allows for improved customized designs that lower the risk of prosthesis loss due to stress shielding. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this study is to explore the optimization of support structures for horizontal pressure vessels using simulation modeling. The research aims to reduce the mass of the support while ensuring structural integrity and identifying opportunities for future improvements in materials and design. Design/methodology/approach: The research was conducted by creating a three-dimensional support model in SolidWorks, compliant with GOST standards. The stress-strain behavior and optimization of the support structure were analyzed using SolidWorks’ Simulation module, which employs the finite element method (FEM). Non-uniform load distributions, such as sinusoidal and parabolic loads, were applied during the loading process to enhance the accuracy of the simulation without incorporating the vessel body itself. Findings: The simulation results showed that optimizing the support structure led to a 15% reduction in its mass. Even though this also resulted in a 23% increase in equivalent stresses in critical areas, the support structure remains safe to operate, with a strength reserve factor under static loads exceeding 2. Research limitations/implications: Further research should include simulations that account for the type and properties of connections between elements, particularly weld calculations. Additionally, future studies could explore the use of higher-grade steels than the tested 09G2C steel to achieve further mass reductions, provided the cost is justifiable. Practical implications: This study is particularly relevant for the design of pressure vessel supports used in vehicles, trailers, and semi-trailers transporting liquids or liquefied hydrocarbon gases. Reducing the mass of support structures can increase payload capacity, offering significant commercial benefits in transportation efficiency. Social implications: A lighter, optimized support structure can contribute to more fuel-efficient transportation of liquid and gas materials, thereby reducing the environmental impact of logistics operations. Originality/value: The originality of this study lies in the combined use of topological and parametric optimization techniques for modeling horizontal pressure vessel supports. The paper provides valuable insights into how simulation-based optimization can lead to significant mass reductions while maintaining structural safety. This research is particularly useful to engineers and designers working on pressure vessel supports for transportation applications. [ABSTRACT FROM AUTHOR]

Rolling stock manufacturers are finding innovative structural solutions to improve the quality and reliability of railway vehicle components. Structural optimization processes represent an effective strategy for reducing manufacturing costs, resulting in geometries that are easier to design and produce combined with innovative materials. In this framework, the present paper proposes the development of a design methodology to innovate a railway bolster beam using topological optimization techniques, assessing the effect of different manufacturing constraints oriented to the casting process. A comprehensive numerical testing campaign was conducted to establish an effective testing procedure. Two different designs were obtained and compared, statically and dynamically, evaluating the difference in terms of mass, mechanical performance and manufacturability. Reductions in stress values up to 70% were observed, along with an 8% increase in the first natural frequency of the component, leading to beneficial effects in terms of stiffness. The methodology shows encouraging results to streamline the design of complex casting components, moving to a new generation of structural railway components. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Railway Science & Engineering is the property of Journal of Railway Science & Engineering Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Using persistent homology to guide optimization has emerged as a novel application of topological data analysis. Existing methods treat persistence calculation as a black box and backpropagate gradients only onto the simplices involved in particular pairs. We show how the cycles and chains used in the persistence calculation can be used to prescribe gradients to larger subsets of the domain. In particular, we show that in a special case, which serves as a building block for general losses, the problem can be solved exactly in linear time. This relies on another contribution of this paper, which eliminates the need to examine a factorial number of permutations of simplices with the same value. We present empirical experiments that show the practical benefits of our algorithm: the number of steps required for the optimization is reduced by an order of magnitude. [ABSTRACT FROM AUTHOR]

The robotic arm is one of the vital components of robot assembly. The purpose of the robotic arm is to transmit power and conduct the desired motion, i.e., translation or rotation. Robotic limbs are designed and constructed to execute certain tasks with a high degree of speed, accuracy, and efficiency. This research focuses on to enhancing the strength-to-weight ratio of robotic arm using certain techniques of additive manufacturing, i.e., topology optimization and lattice structure. Employing the finite element analysis, the impact of weight reduction optimization on structural parameters such as stress and deformation in the current design is assessed using ANSYS R18.1 for FE analysis and Creo parametric 7.0 design software for computer-aided design modeling. Observations reveal that the 0.5 and .4 scale lattice structure designs have deformation of 0.01453mm and 0.01453mm respectively though the generic design has 0.01043mm deformation. Notably, the 0.5 scale lattice of the robotic arm exhibits a 31.08% higher equivalent stress than the generic design with 29.3%. reduction in mass of the robotic arm. These findings highlight the efficacy of lattice structures for optimizing the robotic arm's performance, contributing to advancements in power-efficient robot assembly processes. [ABSTRACT FROM AUTHOR]

Efficient and stable heat dissipation structure is crucial for improving the convective heat transfer performance of thermal protection systems (TPSs) for hypersonic aircraft. However, the heat dissipation wall of the current TPS is limited by a single material and structure, inefficiently dissipating the large amount of accumulated heat generated during the high-speed maneuvering flight of hypersonic aircraft. Here, a convection cooling channel structure of TPS is proposed, which is an innovative multi-level structure inspired by the natural honeycomb. An active cooling channel (PCM-HC) is designed by using a variable-density topology optimization method and filled with phase change material (PCM). Numerical simulations are used to investigate the thermal performance of the PCM-HC wall, focusing on the influence of PCM properties, structural geometric parameters, and PCM types on heat transfer characteristics. The results demonstrate that the honeycomb-like convection cooling channel wall, combined with PCM latent heat of phase change, exhibits superior heat dissipation capability. With a heat flux input of 50 kW/m2, the maximum temperature on the inner wall of PCM-HC is reduced by 12 K to 20 K. Different PCMs have opposing effects on heat transfer performance due to their distinct thermophysical properties. This work can provide a theoretical basis for the design of high-efficiency cooling channel, improving the heat dissipation performance in the TPS of hypersonic aircraft. [ABSTRACT FROM AUTHOR]

In the field of civil aviation, the nose landing gear is a critical component that is prone to damage during taxiing. With the advent of new technologies such as towing taxi-out and hub motors, the nose landing gear faces increasingly complex operational environments, thereby imposing higher performance demands. Ensuring the structural safety of the nose landing gear is fundamental for the successful application of these technologies. However, current research on aircraft nose landing gear under these new conditions is somewhat lacking, particularly in terms of reliable analysis models for real-world scenarios. This study focuses on a typical Class C aircraft, specifically the B-727 model, for which a finite element model of the nose landing gear is developed. Modal testing of the aircraft's nose landing gear is conducted using the impact hammer method, and the results are compared with those from the simulations. The experimental data indicate that the error range for the first seven natural frequencies is between 0.23% and 9.27%, confirming the high accuracy of the developed landing gear model. Furthermore, with towing taxi-out as the primary scenario, a dynamic model of the aircraft towing system is established, and an analysis on the structural strength and topological optimization of the nose landing gear under various conditions, including high speeds and heavy loads, is performed. The results show that the developed model can effectively support the analysis and prediction of the mechanical behavior of the nose landing gear. Under high-speed, heavy-load conditions, the nose landing gear experiences significantly increased loads, with the maximum deformation primarily occurring at the lower section of the shock strut's outer cylinder. However, no damage occurred. Additionally, under these conditions, an optimized structural design for the landing gear was identified, which, while ensuring structural strength, achieves a 22.32% reduction in the mass of the outer cylinder, also ensuring safety in towing taxi-out conditions. [ABSTRACT FROM AUTHOR]

This article describes the technology for manufacturing a metal composite structure of a metal-cutting tool body. The main problem with using metal 3D-printing is its prohibitively high cost. The initial data for carrying out finite element calculations are presented, in particular, the calculation and justification of the selected loads on the drill body arising from metal-cutting forces. The described methodology for designing a digital model of a metal-cutting tool for the purpose of its further production using SLM 3D metal printing methods facilitates the procurement of a digital model characterized by a reduced weight and volume of material. The described design technology involves the production of a thin-walled outer shell that forms the external technological surfaces necessary for the drill body, as well as internal structural elements formed as a result of topological optimization of the product shape. Much attention in this article is paid to the description of the technology for filling internal cavities with a viscous metal polymer, formed as a result of the topological optimization of the original model. Due to this design approach, it is possible to reduce the volume of 3D metal printing by 32%, which amounts to more than USD 135 in value terms. [ABSTRACT FROM AUTHOR]

The present work proposes a comprehensive metaheuristic methodology for the development of a medical robot for the upper limb rehabilitation, which includes the topological optimization of the device, kinematic models (5 DOF), human–robot interface, control and experimental tests. This methodology applies two cutting-edge triads: (1) the three points of view in engineering design (client, designer and community) and (2) the triad formed by three pillars of Industry 4.0 (autonomous machines and systems, additive manufacturing and simulation of virtual environments). By applying the proposed procedure, a robotic mechanism was obtained with a reduction of more than 40% of its initial weight and a human–robot interface with three modes of operation and a biomechanically viable kinematic model for humans. The digital twin instance and its evaluation through therapeutic routines with and without disturbances was assessed; the average RMSEs obtained were 0.08 rad and 0.11 rad, respectively. The proposed methodology is applicable to any medical robot, providing a versatile and effective solution for optimizing the design and development of healthcare devices. It adopts an innovative and scalable approach to enhance their processes. [ABSTRACT FROM AUTHOR]

This paper concerns the optimization of microstructures within a surface when considering the propagation of scalar waves across a periodic row of inclusions embedded within a homogeneous matrix. The approach relies on the low-frequency homogenized model, which consists, in the present case, of some effective jump conditions through a discontinuity within the ambient medium. The topological derivatives of the effective parameters defining these jump conditions are computed from an asymptotic analysis. Their expressions are validated numerically and then used to study the sensitivity of the homogenized model to the geometry in the case of elliptic inclusions. Finally, a topological optimization algorithm is used to minimize a given cost functional. This relies on the expression of the topological derivatives to iteratively perform phase changes in the unit cell characterizing the material, and on FFT-accelerated solvers previously adapted to solve the band cell problems underlying the homogenized model. To illustrate this approach, the resulting procedure is applied to the design of a microstructure that minimizes transmitted fields along a given direction. [ABSTRACT FROM AUTHOR]

Biodigital Architecture and Design emerges in the intersection between nature-based design and digital technologies. This article presents the results of a project that aimed to integrate three-dimensional growth patterns from nature into a stool design series through Computational Design and Additive Manufacturing methods. The project methodology includes (1) Pattern from nature selection, (2) Generative design, (3) 3D printing, including scale models and prototypes, (4) Compression tests, and (5) Generative optimization. Findings indicate that the branching pattern was the lightest-weight pattern while showing the highest specific resistance compared to the other models evaluated. Branching pattern also took the least amount of time and material to print, these findings contribute to the decision-making process for future work. Regarding computational design method, it resulted in several design alternatives, with complex, unpredictable and efficient mechanical behavior geometries. Future work would include to a variety of patterns from nature, generative design, optimizations, and prototypes. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Ordnance Equipment Engineering is the property of Chongqing University of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The efficient development of electric vehicles is essential to drive society towards sustainable development. Designing a lightweight frame is a key strategy to improve the economy and environment, increase energy efficiency, and reduce carbon emissions. Taking an automatic loading and unloading mixer truck as the research object, a force analysis of its frame was conducted under six typical working conditions. A size optimization method based on a hybrid model of the Kriging model and the analytic hierarchy process (AHP) is proposed. An approximate model of the mass and maximum stress of the frame was established using the Kriging model, and the Kriging model was optimized by using the multi-objective genetic optimization algorithm and the AHP method. Meanwhile, topology optimization was introduced to improve the structural performance of the frame and reduce its weight. The optimization results show that the overall weight of the frame is reduced by 11.96% compared to the pre-optimization period, though it still meets the material performance specifications. By comparing the iterative curves of the single Kriging model with those of the AHP model, it can be seen that the initial optimization efficiency of the hybrid model is about twice as much as that of the AHP model, and the final optimization result is improved by about 3.6% compared with the Kriging model. This validates the hybrid model as an effective tool for the multi-objective optimization of electric vehicle frames, providing more efficient and accurate optimization results for frame design. [ABSTRACT FROM AUTHOR]

The use of additive technology—in particular, selective laser melting (SLM)—in producing wire electrodes for electrical discharge machining is considered. By this means it is possible to produce electrodes of high precision and complex geometry, with distinctive properties. In addition, the results of topological optimization in electrode design are presented. Topological optimization permits the production of wire electrodes that are more efficient in the given operating conditions. It is shown that, on the basis of additive technology and optimized electrode geometry with internal supply channels for dielectric liquid, the removal of sludge from the machining area may be improved, with consequent stabilization of the machining process. [ABSTRACT FROM AUTHOR]

Copyright of Rolling Stock (1002-7602) is the property of Rolling Stock Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

As the key component of a five-axis CNC planer-type milling machine, the integral mechanical property of the A/C swing angle milling head directly affects the machining accuracy and stability of the milling machine. Taking the mechanical A/C swing-angle milling head of a five-axis numerical-control gantry milling machine as the research object, the stress deformation characteristics and natural frequency of the swing-angle milling head under actual working conditions were studied using finite-element analysis. Based on the analytical results, it was determined that the cardan frame, with its large mass proportion and strong rigidity of the whole milling head, is the object to be optimized. The topological optimization of the cardan frame, in which achieving the minimum flexibility was the optimization objective, was carried out to determine the quality reduction area. By comparing the simulation results of the cardan frames of three different rib plate structures, it was shown that the cardan frame performance of the ten-type rib plate structure was optimal. The analytical results showed that, when the cardan frame met the design requirements for stiffness and strength, the mass after optimization was reduced by 13.67% compared with the mass before optimization, the first-order natural frequency was increased by 7.9%, and the maximum response amplitude was reduced in all directions to avoid resonance, which was beneficial to the improvement of the dynamic characteristics of the whole machine. At the same time, the rationality and effectiveness of the lightweight design method of the cardan frame were verified, which has strong engineering practicality. The research results provide an important theoretical basis for the optimization of other machine tool gimbals and have important practical significance and application value. [ABSTRACT FROM AUTHOR]

Additive manufacturing allows the creation of geometries otherwise impossible to achieve through traditional technologies in mechanical components. These geometries can be obtained using algorithms to optimize the mass distribution. Topology Optimization algorithms are one of the tools most applied in design for additive manufacturing and lightweight engineering. These optimization techniques require Finite Element Method tools to evaluate and compare the mechanical behavior of different geometrical solutions. The optimization results are closely related to boundary conditions, objectives, and constraints. Therefore, one of the issues is the necessity to evaluate different parameter settings to improve the result in terms of light weight, strength, and easy printability. This article shows a working method for using topological optimization to lighten a connecting rod. The resultant model is optimized considering Additive Manufacturing. [ABSTRACT FROM AUTHOR]

Copyright of Journal of South China University of Technology (Natural Science Edition) is the property of South China University of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A high percentage of failure in pump elements originates from fatigue. This study focuses on the discharge section behavior, made of ductile iron, under dynamic load. An experimental protocol is established to collect the strain under pressurization and depressurization tests at specific locations. These experimental results are used to formulate the ultimate pressure expression function of the strain and the lateral surface of the discharge section and to validate finite element modeling. Fe-Safe is then used to assess the fatigue life cycle using different types of fatigue criteria (Coffin-Manson, Morrow, Goodman, and Soderberg). When the pressure is under 3000 PSI, pumps have an unlimited service life of 107 cycles, regardless of the criterion. However, for a pressure of 3555 PSI, only the Morrow criterion denotes a significant decrease in fatigue life cycles, as it considers the average stress. The topological optimization is then applied to the most critical pump model (with the lowest fatigue life cycle) to increase its fatigue life. Using the solid isotropic material with a penalization approach, the Abaqus Topology Optimization Module is employed. The goal is to reduce the strain energy density while keeping the volume within bounds. According to the findings, a 5% volume reduction causes the strain energy density to decrease from 1.06 to 0.66 106 J/m³. According to Morrow, the fatigue life cycle at 3,555 PSI is 782,425 longer than the initial 309,742 cycles. [ABSTRACT FROM AUTHOR]

Background: Porous cages are considered a promising alternative to high-density cages because their interconnectivity favours bony ingrowth and appropriate stiffness tuning reduces stress shielding and the risk of cage subsidence. Methods: This study proposes three approaches that combine macroscopic topology optimization and micropore design to establish three new types of porous cages by integrating lattices (gyroid, Schwarz, body-centred cubic) with the optimized cage frame. Using these three porous cages along with traditional high-density cages, four ACDF surgical models were developed to compare the mechanical properties of facet articular cartilage, discs, cortical bone, and cages under specific loads. Results: The facet joints in the porous cage groups had lower contact forces than those in the high-density cage group. The intervertebral discs in all models experienced maximum stress at the C5/6 segment. The stress distribution on the cortical bone surface was more uniform in the porous cage groups, leading to increased average stress values. The gyroid, Schwarz, and BCC cage groups showed higher average stress on the C5 cortical bone. The average stress on the surface of porous cages was higher than that on the surface of high-density cages, with the greatest difference observed under the lateral bending condition. The BCC cage demonstrated favourable mechanical stability. Conclusion: The new porous cervical cages satifies requirements of low rigidity and serve as a favourable biological scaffold for bone ingrowth. This study provides valuable insights for the development of next-generation orthopaedic medical devices. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Mechanical Strength / Jixie Qiangdu is the property of Zhengzhou Research Institute of Mechanical Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This paper applies topology optimization in combination with a genetic algorithm to design a coating structure for sound absorption in underwater applications. The coating is designed with a high broadband acoustic absorption of 0.94 ranging from 1 to 10 kHz by optimizing the cavity topology and the dimensions of the embedded steel scatterers. This study demonstrates the application process of the topology optimization with a genetic algorithm method and the optimization results of the optimization process stages. The absorption mechanism of the topology design is analyzed. The effects of different cavity compositions, steel scatterers, design ideas, material parameters, and acoustic incident angles on the sound absorption coefficients are investigated. These acoustic structures and the method provide more ideas for the design of coating structures for underwater sound absorption. [ABSTRACT FROM AUTHOR]

BACKGROUND: Currently, quadrilateral anterior cervical plate (QACP) is a highly prevalent ACP. OBJECTIVE: This study aims to design a novel ACP using topology optimization (TOACP). METHODS: A completed model for C1–C7 cervical segments was established and validated. QACP and TOACP cage systems were implanted within two cervical vertebrae models, respectively, and peak stresses and stress distributions for screw, plate, endplate and cage displacement were investigated under differing exercise modes. RESULTS: Stress levels upon QACP screw were maximized for over-extension exercise (243.3 MPa, 3.35% > TOACP screw). Stress level upon TOACP plate was maximized for over-extension exercise (118.2 MPa, 7.26% > QACP screw). Following QACP cage system implantation, stress on endplate and cage displacement were maximized for extension exercise, which were 27.1%, and 6.3% > TOACP cage system, respectively. Finite element analysis results revealed that topological optimization of the plate can effectively reduce screw stress, thereby enhancing cervical segments' stability during surgery. Furthermore, stress on endplate and cage displacement decreased, indicating great potential in cage sinking and fusion enhancement. CONCLUSIONS: Topological optimization of the plate equips the cage system with advantages in clinical applications and biomechanical performance, providing alternative solutions and a theoretical basis for ACP design. [ABSTRACT FROM AUTHOR]

The natural distribution of stress in the femur is altered when total hip arthroplasty (THA) is performed. In fact, when a stem is inserted inside the femur, there is a variation in stress due to the difference in rigidity between the material with which the stem is made and the femur. This generates the phenomenon of stress shielding. The aim of this study is to design an optimized prosthesis that guarantees an excellent rotational stability and a reduced stress shielding. Methods: Through the finite element method (FEM), the mechanical behavior of the stem subjected to the loads described by ISO 7206-4:2010 is studied. Results: Through topological optimization, there is a reduction in stress shielding in the proximal zone of 31.46%. The addition of ridges on the dorsal side of the stem also improves rotational stability by 27.82%. Conclusions: The decrease in stiffness that is recorded with the optimized stem guarantees a greater distribution of stress on the bone. The presence of dorsal ridges also favors the corticalization of the bone as it loads the bone near the dorsal, ensuring further stability. The perforated prosthesis presented in this study shows an increase in primary stability and an improvement in rotational stability as there is also a bone regrowth inside the prosthesis. [ABSTRACT FROM AUTHOR]

Acoustic metamaterials (AMMs), especially based on hierarchical honeycomb structure and topology-optimized design with suitable mechanical properties and low-frequency band gaps (BGs), have been studied recently. The present work reports a series of anisotropy hierarchical honeycomb structure lattices composed of the cell walls and vertices of regular hexagonal lattice replacement honeycombs of various sizes, as well as improved BG evaluation indicators. The band structures of three different types of unfilled hierarchical honeycomb lattices are calculated and the mechanism of BGs generation is analyzed. To obtain multi-broad BGs in the low-frequency range, the scatterers filling schemes are optimized by using a genetic algorithm (GA). Additionally, the effects of structural/material parameters on the BG characteristics of the optimized structures are discussed. Finally, the transmission loss (TL) experiment verified the optimization of the structures. This paper aims to promote the application of hierarchical honeycomb metamaterials with low-frequency vibration isolation in the industrial field. [ABSTRACT FROM AUTHOR]

Copyright of Automobile Technology & Material is the property of Automobile Technology & Material Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The rapid advancements in 3D printing technologies offer immense design flexibility and the ability to create complex structures with high resolution. Using these cutting-edge technologies and materials (i.e., a polylactic acid and fused deposition modeling), a novel design principle is introduced for a fingerless gripper, achieved through topological optimization. To realize the grasping capabilities, a coiled garter spring made of shape memory alloy (SMA) is incorporated at the end of the flexure beams. Based on the experiments, it is found that the gripper is very quick to respond, taking only 5 s to heat up and 15 s to cool down. This promising performance is achieved by carefully balancing the net force differential between the restoring force of the flexure beam and the force of the SMA coiled garter spring. In addition to its responsiveness, the gripper demonstrates a high force-to-weight ratio of 5.3, allowing it to lift heavy payloads of up to 4.91 N (0.5 kgf ) despite its lightweight design (total weight of 94.2 g). Overall, this work showcases the potential of 3D printed fingerless grippers in terms of high holding strength, lightweight, low cost, and simple fabrication. [ABSTRACT FROM AUTHOR]

In this paper, the flow channel of the radial proton exchange membrane fuel cell (PEMFC) is optimized by the topological optimization method. Using the SNOPT algorithm, a two-dimensional stable constant temperature model is freely constructed in the cyclic sector design domain. Topology optimization aims to maximize the efficiency of PEMFC and minimize the energy dissipation of reaction gas. We analyze radial topology flow channels' mass transfer capacity and cell performance with different maximum volume constraints. The results show that under high current density, the performance of the optimized channel is significantly better than that of the traditional channel. Increasing the maximum volume constraint is beneficial for improving the mass transfer of PEMFC. At 0.6 V, the cell performance of Scheme 4 is 14.9% higher than the serpentine flow channel and 9.5% higher than the parallel flow channel. In addition, in the optimal selection, 3D simulation modeling is carried out for more accurate verification. [ABSTRACT FROM AUTHOR]

Integrated frequency routers, which can guide light with different frequencies to different output ports, are an important kind of nanophotonic device. However, frequency routers with both a compact size and multiple channels are difficult to realize, which limits the application of these frequency routers in nanophotonics. Here, a kind of bandgap optimization algorithm, which consists of the finite element method and topology optimization, is proposed to design a multi-channel frequency router. Channels supporting photonic edge states with different frequencies are built through the synthetic dimension of translational deformation. Due to the help of the developed optimization algorithms, the number of channels and output ports can be increased up to nine while maintaining ultracompact device size. The device operates within a working band of 0.585–0.665 c/a, corresponding to 1.504–1.709 μm when the lattice constant is set as 1 μm, covering the telecom wavelength of 1.55 μm. The average crosstalk is about −11.49 dB. The average extinction ratio is around 16.18 dB. Because the bus of the device can be regarded as a part of a topological rainbow, the results show that the structure is robust to fabrication errors. This method is general, which can be used for different materials and different frequency ranges. The all-dielectric planar configuration of our router is compact, robust, and easy to integrate, providing a new method for on-chip multi-channel broadband information processing. [ABSTRACT FROM AUTHOR]

Arthroplasty is commonly performed to treat advanced osteoarthritis or other degenerative joint conditions; however, it can also be considered for young patients with severe joint damage that significantly limits their functionality and quality of life. Young patients are still at risk of aseptic mobilization and bone resorption due to the phenomenon of stress shielding that causes an uneven distribution of tensions along the femoral contact surface prosthesis. This phenomenon can be limited by choosing the material of the prosthesis appropriately or by varying its stiffness, making sure that its mechanical behavior simulates that of the femur as much as possible. The aim of this study is to evaluate the mechanical strength of a prosthesis optimized both in shape and material and compare the results with a standard titanium prosthesis. Methods: Through three-dimensional modeling and the use of finite element method (FEM) software such as ANSYS, the mechanical behavior of traditional prosthesis and prosthesis optimized topologically respecting the ASTM F2996-13 standard. Results: With topological optimization, there is a stress reduction from 987 MPa to 810 MPa with a mass reduction of 30%. When carbon fiber is used, it is possible to further reduce stress to 509 MPa. Conclusions: The reduction in stress on the femoral stem allows an optimal distribution of the load on the cortical bone, thus decreasing the problem of stress shielding. [ABSTRACT FROM AUTHOR]

The focus of this paper is to compare the results of topological optimization (TO) of the rocker arm for following 3D printing out of AISI 316L stainless steel by the Selective Laser Melting (SLM) method. We used the Altair Inspire software to optimize the shape of the rocker arm. Two variants of optimization were created, first, a variant of optimization without the Shape Control function was carried out, which resulted in a complex mechanical component with an organic shape. This bionic design means more support for the SLM method of Additive Manufacturing (AM) and worse surface quality after their removal. Therefore, a second variant of optimization was produced with the application of the Shape Control function, which positively affects manufacturability and postprocessing. The use of shape control reduced the amount of supports to a minimum, helping to improve the surface finish. [ABSTRACT FROM AUTHOR]

This study focuses on the topological optimization of adhesive overlap joints for structures subjected to longitudinal mechanical loads. The aim is to reduce peak stresses at the joint interface of the elements. Peak stresses in such joints can lead to failure of both the joint and the structure itself. A new approach based on Rational Approximation of Material Properties (RAMP) and the Finite Element Method (FEM) has been proposed to minimize peak stresses in multi-layer composite joints. Using this approach, the Mises peak stresses of the optimal structural joint have been significantly reduced by up to 50% under mechanical loading in the longitudinal direction. The paper includes numerical examples of different types of structural element connections. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Chongqing University of Technology (Natural Science) is the property of Chongqing University of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The problem of topological optimization of a symmetrical double-shear adhesive joint has been solved. The suggested mathematical model of a joint with variable thickness generalizes the classic Holland–Reissner model. The shape of the doubler is described by means of the Bezier curve. Seeking parameters in the optimization problem are coordinates of reference points of the Bezier curve. Both joint length and doubler cross-section area can be considered an objective function. The restriction is applied on stress in adhesive film and doubler. The direct problem of finding the joint stress state at given geometric parameters was solved using the finite difference method. The genetic algorithm was used to solve the optimization problem. In order to improve the convergence of the genetic algorithm, the island model of evolution is suggested, which ensures quick evolution selection and stability of obtained results. The model problem is solved. [ABSTRACT FROM AUTHOR]

The LNG marine loading arm is a critical component for transferring LNG from vessels to onshore receiving stations. However, currently, the operation of LNG marine loading arms is still faced with issues such as a slow docking speed and significant environmental impacts from waves and wind. In this paper, we propose a set of feasible improvement schemes for the traditional LNG marine loading arm based on the theory of inventive problem solving (TRIZ). We utilized tools such as functional models, causal chain analysis, contradiction analysis, and Su-Field model analysis to develop these schemes. Our proposed improvements include using machine vision and automatic control to replace manual work, conducting finite element analysis and topology optimization of the LNG marine loading arm to improve its structure, and innovating the design of the end structure of the LNG discharge arm. [ABSTRACT FROM AUTHOR]

The paper presents the evaluation of selected mechanical properties of PLA filaments used in the production of unmanned aerial vehicles (UAV). The manuscript covers a short description of the principles of pattern design and presents a shortened division of incremental manufacturing technologies. The authors present and argue the choice of material that can be used in the UAV drone design. This material has been subjected to experimental tests in order to assess selected mechanical properties that can be successfully adapted to CAD/CAM/CAE systems in order to conduct engineering analyses. The manuscript presents a discussion on the influence of the method of specimen production on selected mechanical properties, as well as the issue of errors made when measuring selected mechanical properties. In addition to the assessment of the mechanical properties of the selected filament, the manuscript indicates how to adapt the determined material constants to the FEM calculation model and presents the effectiveness of topological optimization in engineering design, which allows to reduce the weight of the drone frame by about at least 20% compared with the value originally assumed. [ABSTRACT FROM AUTHOR]

Porous structures widely exist in nature and artifacts, which can be exploited to reduce structural weight and material usage or improve damage tolerance and energy absorption. In this study, the authors develop an approach to design optimized porous structures with Triply Periodic Minimal Surfaces (TPMSs) in the framework of isogeometric analysis (IGA)-based topological optimization. In the developed method, by controlling the density distribution, the designed porous structures can achieve the optimal mechanical performance without increasing the usage of materials. First, the implicit functions of the TPMSs are adopted to design several types of porous elements parametrically. Second, to reduce the cost of computation, the authors propose an equivalent method to forecast the elastic modulus of these porous elements with different densities. Subsequently, the relationships of different porous elements between the elastic modulus and the relative density are constructed. Third, the IGA-based porous topological optimization is developed to obtain an optimal density distribution, which solves a volume constrained compliance minimization problem based on IGA. Finally, an optimum heterogeneous porous structure is generated based on the optimized density distribution. Experimental results demonstrate the effectiveness and efficiency of the proposed method. [ABSTRACT FROM AUTHOR]

In the present paper, a new approach to identifying an arbitrary number of inclusions, their geometry and their location in 2D and 3D structures using topological optimization was proposed. The new approach was based on the lack of initial information about the geometry of the inclusions and their location in the structure. The numerical solutions were obtained by the finite element method in combination with the method of moving asymptotes. The convergence of the finite element method at the coincidence of functions and their derivatives was analyzed. Results with an error of no more than 0.5%, i.e., almost exact solutions, were obtained. Identification at impact on the plate temperature and heat flux by solving the inverse problem of heat conduction was produced. Topological optimization for identifying an arbitrary number of inclusions, their geometry and their location in 2D problems was investigated. [ABSTRACT FROM AUTHOR]

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An upright is the most crucial component of the suspension system of an All-terrain vehicle. It acts as a link for other component such as suspension arms, drive axle, steering tie rod, wheel hub, and brake calliper enabling a smooth comfortable ride. The upright has to withstand the entire force experienced during the dynamics of the vehicle before the energy is dampened by the coil-overs. The brake calliper is mounted on the upright and thus it has to withstand the forces generated during braking. Considering these factors, the design of the upright has to be highly efficient and done with utmost precision ensuring no or minimum failure. This paper outlines the design, analysis and optimization of the upright to be used in the ATV that will participate in BAJA SAE events of India and USA. The basic sketch necessary to design the upright is created in the form of a line diagram of the front geometry suspension system in Solid works. This geometry is then analysed using LOTUS software ensuring a near to perfect ride and handling. The 3D CAD model of the upright is designed in Solid works with respect to the front geometry of the suspension. The static structural analysis of the model is then performed on ANSYS mechanical followed by topological optimization of the model. Based on the results from this analysis, the improved CAD model of the upright has been designed and analysed. The main objective of this paper is to come up with a highly optimized design that ensures a high factor of safety while maintaining a lower weight. These optimizations proved to be helpful by reducing the weight of the component around 60 grams and increasing the factor of safety from 1.58 to 2.43. [ABSTRACT FROM AUTHOR]

This paper proposes the framework for reliability-based design optimization (RBDO) of structural elements with an example based on the corrugated web I-girder. It tackles the problem of topological optimization of corroding structures with uncertainties. Engineering restrictions follow a concept of the limit states (LS) and extend it for stability and eigenfrequency assessment. The reliability constraints include all the LS; they are computed according to first- and second-order reliability methods. The RBDO example minimizes the bridge girder cross-section while satisfying the structural reliability level for the ultimate and the serviceability limit states, stability, and eigenfrequency. It takes into consideration two uncorrelated random effects, i.e., manufacturing imperfection and corrosion. They are both Gaussian; the first of them is applied at assembly time, while the second is applied according to the time series. The example confronts three independent FEM models with an increasing level of detailing, and compares RBDO results for three concurrent probabilistic methods, i.e., the iterative stochastic perturbation technique (ISPT), the semi-analytical method, and the Monte Carlo simulation. This study proves that the RBDO analysis is feasible even for computationally demanding structures, can support automation of structural design, and that the level of detailing in the FEM models influences its results. Finally, it exemplifies that reliability restrictions for LS are much more rigorous than for their deterministic counterparts, and that the fastest ISPT method is sufficiently accurate for probabilistic calculations in this RBDO. [ABSTRACT FROM AUTHOR]

We propose applying topological optimization methods based on measuring temperature and heat fluxes to estimate the thermal conductivity of inhomogeneous thermally conductive plates and determine the shape and location of foreign inclusions. Examples of plates subjected to external heat fluxes and heat sources are considered. The solutions are obtained with the help of the finite element method combined with the method of moving asymptotes. The results show that identification accuracy depends on the defined boundary conditions, the source intensity value, heat fluxes, temperature distribution and the shape of the inclusions. For the problem of 18 circular inclusions under different heat fluxes, identification accuracy increases with increasing source intensity values. [ABSTRACT FROM AUTHOR]

As one of the important load-bearing components of a truck, the drive axle housing must meet the requirements of stiffness and strength. The traditional design method uses redundancy design to meet the performance requirements. The joint design between the three-dimensional mathematical model and finite element model is adopted, and the optimal design of the drive axle housing is realized based on topology optimization and multiobjective optimization. Firstly, the static analysis of the drive axle housing of a rear axle drive truck was carried out with four typical working conditions. It was concluded that the four working conditions all operate under the yield limit of the material, and it was found that the maximum equivalent stress of the four working conditions occurs at the step of the half-shaft casing. Among the four working conditions, the most critical one is the maximum vertical force working condition. Then, based on the maximum vertical force working condition, the fatigue life analysis is conducted, and the minimum fatigue life appears at the transition position of the half-shaft sleeve and the arc transition position of the main reducer chamber. The remaining parts can meet the design requirements. The overall safety factor of the drive axle housing is mainly between 1 and 5 when operating under this working condition. Then, through modal analysis, the first to sixth natural frequency and vibration modes of the drive axle housing are extracted. Based on the modal analysis, the dynamic characteristics of the drive axle housing are further studied by harmonic response analysis and random vibration analysis. Finally, two kinds of lightweight optimization schemes for the drive axle housing are given. Topology optimization reduces the mass of the drive axle housing by 17.4%, but the overall performance slightly decreases. Then, the five dimensional parameters of the drive axle housing are selected as design variables. The mass, maximum deformation, equivalent stress, service life, and the first-, second- and third-order natural frequencies are defined as objective functions. Through the optimal space-filling design method, the experimental designs are performed and the sample points are obtained. Based on the results of experiment design, the multiobjective genetic algorithm and response surface method are combined to optimize the objective functions. The analysis results show that the mass is reduced by 4.35%, the equivalent stress is reduced by 21.05%, the minimum life is increased by 72.28%, and the first-, second-, and third-order natural frequency are also increased to varying degrees. Two different optimization strategies are provided for the design of the drive axle housing. [ABSTRACT FROM AUTHOR]

The aim of this study is to promote the industrial use of "lattice" structures in metal components made with Electron Beam Melting (EBM) technology. The degree of customization and the level of geometric complexity achieved with EBM technology in the production of metal components in the Aerospace and Racing sectors, favors the use of lighter and more performing designs characterized by reticular (or "lattice") structures. Starting from the original massive design of the component and taking into account the geometric constraints and load conditions acting on the component, the search for the new design takes place in a software environment through the topological optimization process. At the end of the process, the optimized design is created by replacing the solid parts with a unit cell that is repeated periodically. From the comparison between the component with original layout, built using the standard Melt theme of EBM technology, and the equivalent component with optimized layout, created with the Net theme of the same technology, the advantage of using reticular structures to lighten the components and the possibility offered by EBM technology to practically implement these structures are highlighted. The search for lighter and more performing designs for metal components promotes the use of "lattice" structures, which can be created by exploiting the potential of Additive Manufacturing technologies. The possibility of creating very complex geometries makes EBM technology perfect for sectors where particular characteristics are required in the components produced, such as the Aerospace and the Racing sector. The existence of the Net theme also ensures that it is possible to print reticular structures with EBM technology, that allow to reduce the weight of the components and, at the same time, improve performance. [ABSTRACT FROM AUTHOR]

The reliability and performance qualification of additively manufactured metal parts is essential for their successful and safe use in engineering applications. Additive Manufacturing (AM) allows parts to be produced more easily than traditional manufacturing. Arc Wire Direct Energy Deposition (AW-DED) is one of the lesser-known metal additive manufacturing technologies. It has enormous potential for large-scale 3D printing applications in the aerospace industry. However, in the aerospace industry, one of the main challenges today is to reduce the weight of components without compromising their structural functionality. Topology optimization offers design engineers the opportunity to create lightweight and complex structural parts. In arc wire direct energy deposition (AW-DED) processes, processing parameters affect material microstructure features, overall part quality, and integrity, as well as bulk mechanical behavior. To address such challenges, the investigation presented in this paper describes a novel digital design approach combining topology optimization, process simulations, and size optimization of the tool components used in the aerospace industry to address effects caused during manufacturing by using Finite Element Modeling (FEM) simulations. This can lead to reduced costs, development time, material consumption, and product weight. Due to the flexibility mentioned above, parts designed for AM have the same structural load as conventional parts but with reduced mass and better part design. The results of this application are discussed in depth in this paper. This is a new research work with useful results and conclusions in the methodology for the evaluation of mechanical behavior of topologically optimized metal additive manufactured components. For this purpose, aerospace fixtures have been topologically designed by means of AW-DED-process-oriented techniques. Aerospace fixtures are normally used in the aerospace industry to support and hold various components. These new design paradigms make it possible to save on material costs oriented toward more sustainable and flexible manufacturing. [ABSTRACT FROM AUTHOR]

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