Dynamic design of stiffeners for a typical panel using topology optimization and finite element analysis

In this study, a topology optimization method based on combined mechanical analysis and variable density is presented for a large-scale casting structure with complex thin-walled structures. First, the mechanical analysis model of the frame is established, the first-order bending and torsional modes and stiffness values of the all-cast aluminum frame are obtained, and the basic mechanical parameters such as bending/torsional mode and stiffness constraints needed for topology optimization are defined. Using the variable density method, unneeded material that can be removed from the casting structure is identified. According to the design requirements, the optimization objective function and constraint conditions are established, and the variable density method is used to solve the problem. Analysis of the mechanical results before and after topology optimization reveals that the modes and stiffness values are larger than the target values, and the mass of the frame is reduced by 10.2 kg (i.e. 13.9%) compared with the original design. The application of the combined mechanical analysis and variable density method to a casting structure can effectively achieve lightweight design.

Introduction (problem statement and relevance). Currently, mobile driverless transport and technological means are widely used for automation of work processes and remote control over a vehicle, excluding immediate human attendance in dangerous areas. Generally, such vehicles feature an electric powerplant while using batteries as energy storage devices. In order to reduce the number of operations during such vehicle driving, it is convenient to use a running gear design that is symmetric relative to its longitudinal and transverse planes. Reducing energy consumption will allow increasing in energy efficiency when performing transport and other technological operations. One of the ways to improve energy efficiency is to reduce the weight of elements of such vehicles. This can be achieved by using materials with high specific strength, such as aluminum alloys, and by developing optimum loading patterns for such element structures. The object of the study is a driverless 4x4 vehicle with the fully loaded weight of 830 kg. The research subject is the methods of optimum designing of vehicle load-bearing structures and their use taking into account the operating conditions. The purpose of the study is to develop the methodology for designing suspension elements for a vehicle with a symmetric design of the running gear made of aluminum alloy taking into account the loading modes.Methodology and research methods. The paper presents a dynamic mathematical model of the wheeled vehicle for determination of loads created in a program for rigid bodies dynamics modeling, the methodology for bringing the loads to one suspension unit (front left wheel), loading patterns for suspension elements obtained with the use of topological optimization and strength calculations performed with application of the finite element method confirming the design functionality.Scientific novelty and results. The paper presents the method for bringing the loads obtained for all suspension elements to the front left point, since the driverless vehicle has a symmetrical running gear design. Taking this into account, a rigid-body dynamic model and an algorithm for processing the obtained loads for a finite element model were developed. Also, typical modes of vehicle loading were selected. The loads were distributed among the following types: operational, extreme and emergency ones. Recommendations were given for the choice of restrictions when conducting topological optimization depending on the mode type. As a result, loading patterns for suspension guiding device elements were obtained. Check calculations were carried out to confirm the design functionality.Practical significance. The obtained results can be used in development of highly loaded elements of wheeled vehicles.

Topology optimization design of the main structure of 6-DOF manipulator based on the variable density method

Structural topology optimization is a crucial approach for achieving lightweight design. An effective topology optimization algorithm must strike a balance between the objective functions, constraints, and design variables, which essentially reflects the symmetry and tradeoff between the objective and constraints. In this study, a topology optimization method grounded in load path theory is proposed. Element bearing capacity is quantified using the element birth and death method, with an explicit formulation derived via finite element theory. The effectiveness in evaluating structural performance is assessed through comparisons with stress distributions and topology optimization density maps. In addition, a novel evaluation index for element bearing capacity is proposed as the objective function in the topology optimization model, which is validated through thin plate optimization. Subsequently, sensitivity redistribution mitigates checkerboard patterns, while mesh filtering suppresses multi-branch structures and prevents local optima. The method is applied for the lightweight design of a triangular arm, with results benchmarked against the variable density method, demonstrating the feasibility and effectiveness of the proposed method. The element bearing capacity seeks to homogenize the load distribution of each element; the technique in this study can be extended to the optimization of symmetric structures.

This paper presents the direct application of topology optimization to the design of shape memory alloy (SMA) thermal actuators. Because SMAs exhibit strongly nonlinear, temperature‐dependent material behavior, designing effective multidimensional SMA actuator structures is a challenging task. We pursue the use of topology optimization to address this problem. Conventional material scaling topology optimization approaches are hampered by the complexity of the SMA constitutive behavior combined with large actuator deflections. Therefore, for topology optimization we employ the element connectivity parameterization approach, which offers improved analysis convergence and robustness, as well as an unambiguous treatment of nonlinear materials. A path‐independent SMA constitutive model, aimed particularly at the NiTi R‐phase transformation, is employed, allowing efficient adjoint sensitivity analysis. The effectiveness of the proposed SMA topology optimization is demonstrated by numerical examples of constrained and unconstrained formulations of actuator stroke maximization, which provide insight into the characteristics of optimal SMA actuators. Copyright © 2011 John Wiley & Sons, Ltd.

In this paper, an optimum rib layout design method for reducing radiated noise is proposed based on topology optimization and acoustic contribution analysis. According to radiated noise depends on acoustic transfer vector (ATV) and normal velocity, the influence of rib layout on ATV is analyzed and it is found rib layout has little influence on ATV. Only if a region has maximum acoustic contribution, the normal velocities on this region can have the most remarkable influence on radiated noise. So the determination procedure of region with maximum acoustic contribution is introduced. Based on this, the topology optimization model is established to minimize the normal velocities on this region. Ribs can be arranged according to the optimum topologies to reduce the normal velocities, which in turn results in a reduction of radiated noise. The topology optimization model is used to obtain the optimal rib layout by taking a plate-like structure as an example. The plate is fixed along all side edges and excited by a time-harmonic external point load with different prescribed frequencies. The radiated noise is simulated using the finite element method and boundary element method. Four plates are manufactured according to the optimal rib layouts for different single frequency excitation. Modal test and sound measurement are conducted to validate the proposed method. The influence of loading position on the topology optimization results is also investigated and discussed.

In this work, the topology optimization of a mortar base plate is analysed under impact loading conditions. Usually, in this case, only ordinary topology optimization under volume constraints is considered. However, to reduce the quality of the mortar base plate and facilitate engineering applications, the topological optimization problem of the continuum of the base plate under the engineering and quality constraint is considered. A finite element model has been established and verified by testing for the mortar base plate. The variable density method was used to obtain the topological optimization results of the base plate based on the force transmission path, and then the structure was reconstructed. The mass of the optimization model of the base plate is 12.78% lower than that of the original model. In comparison with the original base plate before optimization, the results show that the maximum deformation and stress of the base plate decreased by 16.85% and 35.52%, respectively. Also, the firing stability of the mortar meets requirements, which not only meet the design requirement but also provide a reference for the performance improvement and structural optimization design of the base plate.

Random variable of thermo-mechanical coupling (TMC) structure is analyzed first, then the topology optimization model of TMC compliant mechanism is established. According to the uncertainty factors such as temperature, load, volume ratio and thermal expansion coefficient in the process of topology optimization, the robust reliability optimal design method is introduced into the topology optimization process. The various factors on the sensitivity of topology optimization process is analyzed, the best match between various factors is find out, which make the product has robust reliability for the change of the uncertainty. The residual analysis for the most sensitive factors is carried out. Finally the correctness and validity of the method is verified with an example. Introduction When we study the compliant mechanisms by adopting topological optimization method, we only need to give design domain and allocate input and output position, no need from the perspective of a known rigidity. The mechanism come from this method have a input and output relationship of optimized “force—displacement”, thus it attracts people’s attention. Topology optimization research is developing from certain topology optimization direction to reliable topology optimization direction. Jinqing Zhan proposed a reliable topology optimization method of compliant mechanism based on infrastructure method. KHARMANDA proposed a reliable topology optimization method. Zhaokun Li proposed a geometric nonlinear topology optimization research method based on reliable compliant mechanism. Their research turned out that the mechanism based on reliable topology optimization is more reasonable than the mechanism based on certain topology optimization. Yongcong Kuang build a level set function to design variable, stiffness minimization, and proposed corresponding optimization algorithm. Mingtao Cui established a monolithic compliant mechanism multi-target reliable topology optimization design dual mathematical model. This paper combines topology optimization process of compliant mechanism and robust reliability optimal design, analyzes the sensitivity of uncertainty random variables such as design domain’s size, external load and temperature in topology optimization process. Then get the best combination among these random variables. Random Variable Coupling Field Analysis Hot objects will produce thermal expansion, thus caused by the thermal deformation and displacement of combined action of mechanical load and temperature load structure called a hot solid coupling structure, the finite element balance equation :

For the lightweight design of composite sandwich corrugated structures, a new topology optimization design scheme is proposed using the variable density method. Multi-working conditions static analysis of the composite sandwich corrugated structure is carried out by finite element software. Then, the topology optimization is carried out by using the minimum flexibility method. Finally, the results of different working conditions are coupled to propose a new composite sandwich corrugated structure. The results indicate that the structure has a weight reduction of 34% and exhibits periodicity and continuity while also meeting the necessary mechanical properties to fulfill the engineering requirements. The optimization of composite sandwich corrugated structures has been achieved, providing a new approach to the lightweight design of composite sandwich structures.

Proton exchange membrane water electrolyzers (PEMWEs) are a promising technology for producing clean hydrogen, but their widespread commercialization is limited by high costs, especially due to their high loadings of expensive iridium-based catalysts. This study focuses on the development of a model to simulate the physics of the anode catalyst layer in PEMWEs and the use of topology optimization to search for an optimal structure. The goal is to maximize cell performance by controlling the volume fractions of electrolyte and carbon-supported catalyst materials. By optimizing the structure of the anode catalyst layer using topology optimization, a significant increase in electrochemical reaction by approximately 40% compared to a case with the homogeneously distributed electrode can be achieved. This could be a crucial step towards developing high-performance PEMWE systems that could be used to store renewable energy and reduce reliance on traditional fossil fuels.

The application of steel based Additive Manufacturing (AM) processes on the design of a steel node for a tensegrity structure has been explored with the use of topology optimisation as the form finding method. AM bears the potential of increasing efficiency by reducing processing steps, material use and labor intensity, and offers a feasible manufacturing solution for structural building elements with complex geometry and function. Based on the redesign of an existing steel node, a number of design iterations have been developed and benchmarked using topology optimisation method, followed by a further rationalized design process for AM production. A comparison has also been performed between the new and the conventional design and resulted in insights into the new opportunities and the design freedom created by AM on production of metallic elements for the building industry.

Thin perforated Steel Plate Shear Walls (SPSWs) are among the most common types of seismic energy dissipation systems to protect the main boundary components of SPSWs from fatal fractures in the high-risk zones. In this paper, the cyclic behavior of the different circular hole patterns under cyclic loading is reported. Based on the experimental results, it can be concluded that a change in the perforation pattern of the circular holes leads to a change in the locations of the fracture tendency over the web plate, especially at the plate-frame interactions. Accordingly, the cyclic responses of the tested specimens were simulated by finite element method using the ABAQUS package. Likewise, perforated shear panels with a new perforation pattern obtained by implementing Topology Optimization (TO) were proposed. It was found that the ultimate shear strength of the specimen with the proposed TO perforation pattern was higher than that of the other specimens. In addition, theoretical equations using the Plate-Frame Interaction (PFI) method were used to predict the shear strength and initial stiffness of the considered specimens. The theoretical results showed that the proposed reduced coefficients relationships cannot accurately predict the shear strength and initial stiffness of the considered perforated shear panels. Therefore, the reduced coefficients should be adopted in the theoretical equations based on the obtained experimental and numerical results. Finally, with the results of this study, the shear strength and initial stiffness of these types of perforated shear panels can be predicted by PFI method.

In allusion to a certain kind of bracket of work cabin overhead support equipment components of the special vehicle, taking OptiStruct software as optimization design platform, the topology optimization of the bracket is carried out by using variable density method. The geometry model of the bracket is rebuilt and the finite element analysis of the bracket is carried out, then the stress and deformation of before and after optimization are compared. The results show that the topology optimization method is an effective optimization method to carry out topology optimization of mechanical loading structure with FEA method. The model and approach adopted in this paper provide an important design reference to the mechanical structure and components lightweighting design.

In the Formula Student Racing Car, the frame is a fundamental component that supports the body. The frame’s anti-deformation ability will impact the four-wheel positioning parameters of the car, which subsequently affect the car’s stability. The quality of the frame directly determines the power and efficiency of the racing car, making the frame crucial to the overall race performance. Therefore, researching lightweight frame design is particularly important to enhance frame performance and reduce its total weight. In this paper, based on the variable density method, the global topology optimization of the frame is carried out to obtain the distribution of the frame material, realize the efficient utilization of the material, and improve the torsional stiffness of the frame. Compared with the previous local topology optimization, the global topology optimization involves a wider range, and the results are more accurate. Based on the adjoint variable method, the sensitivity analysis of the frame is carried out to obtain the influence level of each design variable. The size of the frame is optimized according to the variables with high influence levels. After optimization, the total mass of the frame is reduced by 12.8%; the performance in terms of maximum displacement and maximum stress is improved; and the lightweight design of the frame is realized as a whole.

Topology optimization based on the density method commonly employs the optimality criteria (OC) method. However, this method needs certain arbitrary parameters to be set, and the results will depend on those parameters. We propose a modified OC method that does not require those parameters. Our proposed method was developed based on the concept of Newton's method. The optimization problem is to minimize the strain energy. In this article, we perform topology optimization analysis for the 2‐dimensional static problem, the 3‐dimensional static problem, and the 3‐dimensional dynamic oscillation problem. Topology optimization for the 2‐dimensional static problem is used to confirm the usefulness and reliability of the proposed method, and finally topology optimization for the 3‐dimensional dynamic oscillation problem is performed. In the dynamic oscillation problem, in order to derive the self‐adjoint, the strain energy is regarded as the work, and is formulated separately for when it takes positive and negative values. The results of topology optimization for the 2‐dimensional static problem demonstrate that our proposed method does not depend on the setting of arbitrary parameters. In conclusion, this article shows that in the three problems, our proposed method can quickly produce clearer results than the conventional OC method.