Research On Structural Shape Optimization Method Based On Integral - Local

Structural shape optimization achieve the goal by changing the shape of designing boundary. Such as Increase the structural strength and stiffness, reduction of stress concentration increase natural frequency of the equipment,etc. But during the iterations of Structural shape optimization,the shape of designing boundary will change with design variables.In the meantime, the element stiffness matrix and the design variables are non-linear related in process of optimization. And in the shape optimization usually need to conduct mechanical analysis. For these reasons, the large and complicated engineering structure will face difficulties of large amount of calculation. If only optimize the local shape,the computer will need to do a lot of unnecessary computation. By using new numerical methods or improving computer hardware configuration to solve large-scale structural local optimization problem of, may obviously more difficult, also do not have universality. In order to eliminate redundant computation, the best way is only optimizing local model of the whole model.This article discusses the feasibility the global-local method can be applied to structural shape optimization which is based on the finite element method. Meanwhile,in the Structural shape optimization the designing boundary is describe by super elliptic parameterized equations to verify the feasible of this designing boundary’s description method. And the article offers the way to amend the cutting edge interpolation error.The finite element simulation results shows, the global-local method can significantly improve the efficiency of shape optimization under the premise of guarantee the accuracy of the results.Thus it becomes very easy to describe and obtain optimal transition circular arc shape just making use of the optimization module provided in a commercial finite element package due to the super elliptic parameterized equations have only3design variables.First,Take for example,the classical question of elasticity just about centre hole’s stress concentration in infinite plane, applied the global-local method in structural shape optimization, and solved the problem of huge computation and inefficiency in engineering structural local shape optimization. The solutions having been given to solve the two basic problem:fixed cutting boundary and variable cutting boundary, which may meet in local shape optimization.The results shows, design boundary shape change has great influence on the accuracy of cutting-boundary’s displacement interpolation,and Application method described in this article can effectively solve a series of problems in engineering structural local shape optimization, meanwhile, ensuring the accuracy of results.This will lay the foundation for the future obtain optimal throat’s transition circular arc shape of open front mechanical power press.Then the100t open front mechanical power press finite element model is created by using ANSYS program’s APDL.To counter the characteristics of finite element analysis and actual working state, the machine’s statics analysis is given by using different solver, so it is possible to compare the times and hardware costs.At last,this paper optimized the throat’s lower transition circular arc shape of open front mechanical power press by using fixed cutting boundary method、variable cutting boundary and super elliptic method according to the analysis and results above.the results shows,the throat’s maximum stress drops to70.682MPa from242.32MPa, the result is pretty clear.