Research On Reliability-based Topology Optimization Of Compliant Gripper Mechanism Via SERA Method

Compliant mechanism obtains motion through its own deformation,or the transmission of force and displacement.Because the compliant mechanism can be operated without hinges and other moving pairs during work,and has the advantages of no friction,no transmission clearance,and a small number of structural working parts,it has gained wide attention and application.The topology optimization method only needs to get the design domain of the structure and the relevant information of the input and output to complete the design of the structure in the design.This method is very suitable for the design of the current compliant mechanism.In engineering practice,there are many uncertain factors in various parameters of the structure,such as the geometric size of the structure,the applied load,and the material performance.These uncertain factors may cause the performance of the structure to decrease or even fail.Therefore,the related research on the influence of uncertain factors on the structure has very important value,and it is very necessary to control the influence of uncertain factors within the feasible range..In this dissertation,based on the Sequential Element Rejection and Admission(SERA)method,an in-depth study on the optimal design of the compliant mechanism is conducted.The main research contents are as follows:(1)A kind of SERA method continuum structure topology optimization ideas is provided here.In this dissertation,SERA method is used to carry out related research on topology optimization.The method of solving the topology optimization of the SERA method is introduced in detail,and the implementation method of the rejection and admission criteria is described.The materials are converted to each other in the given two material domains through the rejection and admission criteria,and the optimal topology is finally obtained.By comparing with other classical approaches,the effectiveness of this idea is verified.(2)A reliability-based optimization method for the compliance mechanism under the FORM-SERA framework is proposed.Taking the flexible clamping mechanism as an example,a reliability optimization model is established.The First-Order Reliability Method(FORM)and SERA method are used to find solution of the optimization.According to the reliability constraints,random variables such as the geometry sizes and the external loads are corrected and then returned to the optimal design of the compliance mechanism deformation.(3)An evaluation method of topology optimization results combining simulation analysis and physical experiment is given.Simulation analysis of the extraction of the topological results,processing and manufacturing of the obtained optimal topology by additive manufacturing approach,and further verification of the structure through the method of physical test,and finally the feasibility of the method is proved by the case of compliant gripper mechanism.(4)A topology optimization method of compliant mechanism based on stress constraints is proposed.Based on the design concept of full stress,In the process of topology optimization,the total volume fraction is used to control global stress level and to meet the required stress strength conditions of the structure,and a more reasonable topology is obtained.The numerical examples prove the effectiveness and correctness of the method.