Topology Optimization Of Continuum Structure Based On The Method Of Bi-directional Evolutionary Structural Optimization

With the development of computer technology and the advanced manufacturing technology,the structural topology optimization method possesses important theoretical and engineering application values.The evolutionary structural optimization(ESO)method is easily utilized to be programmed,and has been applied to wide engineering fields,and may be adopted to obtain the optimal structural topology with black/ white distribution material property.However,it's difficult to solve the problem of multiple constraint topology optimization by using it.In this paper,for the continuum topology optimization problem,the bi-directional evolutionary structural optimization method is improved and developed.So that it can be extended to multiple constraint optimization problems and is expanded to more engineering application problems.Firstly,the characteristics of existed structural topology optimization methods are carefully been investigated,and the essential reason of the success of evolutionary structural optimization methods is analyzed.The relationship between the stiffness and the topology variables is built by using the rational approximation for material properties(RAMP),on the basis of the problem of stiffness constrained optimization.In order to deal with the problem of checkerboard,an improved mesh filter technology is proposed.Then,a set of unified criteria for element removals and additions is proposed to improve the accuracy of structural optimization.Secondly,structural strength,stiffness,reliability,and other requirements often must be considered in engineering practice,the minimizing volume topology optimization problems with multiple displacement constraints,and with multiple displacement constraints and compliance constraint,are investigated in this paper.The relationship between the displacement and the topology variables is built by using the rational approximation for material properties(RAMP),based on the existing bi-directional evolutionary structural optimization.Then,in order to avoid the non-differentiable defects of the closed-form solutions,a mapping function is introduced,and the calculation formula of element sensitivities and a novel evolutionary structural optimization algorithm are given.Finally,the aforementioned improved optimization algorithms are programmed,and a lotof simulations are made.The improved optimization algorithms can solve the topology optimization problem with multiple constraints,and may be adopted to obtain the optimal topology with black/ white distribution material property.It is concluded that from the results obtained that the proposed method possesses good reliability and efficiency,and good theoretical and engineering application values.