Research On The Evolutionary Structural Topology Optimization Based On The Element Bearing Capacity

Topology optimization can reconstruct the topological form of structure according to constraints,loads and optimization objectives in the conceptual design stage,which is an important way to achieve lightweight design.However,because of the imperfect topology optimization theory,the phenomenon of numerical instability will appear in the process of optimization,which makes the optimization results fall into the local optimal solution.How to avoid the local optimal solution is a problem that must be solved in the process of topology optimization.The transfer load path can reflect the bearing capacity of the structure and the different topological structures correspond to different the load transfer path.The load transfer path can well indicate the direction of topology optimization,avoiding the optimization result falling into the local optimal solution,but its disadvantage is not a explicit expression.Therefore,aiming at putting forward the topology optimization method based on the load transfer path,this paper focuses on these key issues such as theoretical verification and visualization of the transfer load path,topology optimization based on the load transfer path,and so on.The following works have been completed:(1)The new load transfer path concept,which we name it as the element bearing capacity,based on the existing application of the technique of element birth and death;then,the new formula of the element bearing capacity is deduced with the finite element theory.Besides,compared with the structure stress contour plot,the visualization of the element bearing capacity combined with vector diagram and RGB diagram can clearly reflect the bearing performance of the structure.(2)Because the element bearing can reflect the performance of structure,the unique bearing capacity is defined.Then,the optimization function of the unique bearing capacity is demonstrated.In the end,the new topology method based on the unique bearing capacity is put forward to optimizing the truss structure and plate structure.(3)To solve the problem of numerical instability in the new method,the sensitivity redistribution method of the element bearing capacity is used to redistributed the sensitivity of the filter element,and the checkerboard in the optimization process is eliminated.Then,the filter radius is selected by the grid filtering method,which can be used to suppress the multiple branch structure when the finite element mesh is concentrated.Through this two steps,the optimal results can avoid falling into the local optimal solution.(4)With the two development of ANSYS,the proposed topology optimization programme is embedded into ANSYS,which is a visualization platform model of topology optimization method.In addition,we set the lightweight design of triangular arm as an example.Comparing the optimization results with the maturity topology optimization method,the feasibility of the new method can be proved.