Research Of Topology Optimization Method Based On SIMP Method For Stiffness And Fatigue Constraints

The topology optimization method based on Solid Isotropic Material with Penalization(SIMP)has been widely used in engineering practice,and it can be used to provide conceptual guidance for structural lightweight design.With the emergence and development of 3D printing technology,the fabrication of complex topologies has become possible,thus promoting theoretical and applied research on structural topology optimization.Most of the current research focuses on the optimization of structural stiffness or static strength,and relatively little on the optimization of structural fatigue performance;and fatigue strength,as an important index of structural design,is still a relatively new research field in topology optimization design.In this paper,we take the minimization of structural volume(i.e.,mass),which is more in line with the demand of structural lightweight,as the optimization goal,and carry out the research of topology optimization method based on SIMP method with the constraints of stiffness and fatigue,and the main research contents and results are as follows.(1)For the optimal design of structures in engineering practice usually need to meet certain stiffness conditions and fatigue design requirements,the method of implementing stiffness and fatigue constraints on the structure in topology optimization is studied.The method of implementing stiffness and fatigue constraints in topology optimization is investigated,in which the stiffness constraint is achieved by constraining the strain energy of the structure;the quasi-static analysis of the structure with sinusoidal constant amplitude load is carried out by using the finite element analysis theory,and the stress amplitude and average stress of each unit in the structure are calculated by using the von-Mises equivalent force criterion,and the fatigue strength of the structure is measured by the Soderberg formula,so as to realize the fatigue constraint in topology optimization.Finally,a topology optimization model is established with the minimization of structural volume as the objective function and the structural stiffness and fatigue as the constraints.(2)According to the topology optimization method proposed in this paper,a MATLAB optimization program was written.The effectiveness and rationality of the optimization method under the requirements of both stiffness and infinite fatigue life were verified through the optimized design of two structural optimization cases and the comparative analysis of the optimization results.(3)The topological structure specimens were prepared and fatigue tests were conducted using 3D printing technology.The test results show that under the same load,the fatigue life of the topology specimens obtained by the proposed method is longer than that of the topology specimens based on stiffness optimization,which is at least 21% higher,which verifies the effectiveness of the topology optimization method proposed in this paper and provides technical support for the practical application of the topology optimization method based on SIMP method.