Research On Efficient Algorithm For Fail-safe Structural Topology Optimization

The design with high material utilization rate can be obtained by structural topology optimization method.Because the material utilization rate is increased to the limit,the design with traditional topology optimization method often lacks the ability to resist risks.Fail-safe topology optimization method combines the simplified structural local failure model with the density-based optimization algorithm to modify the direction of the traditional structural topology optimization through the influence of the local failure of the structure on the sensitivity information,so as to obtain a better topology design with strong redundancy and less sensitive to the local failure of the structure.The basic theory of topology optimization is described first,then introduces the basic content of the fail-safe structure topology optimization method in detail,which is different from the conventional topology optimization method of continuum structure and the fail-safe structure optimization of truss structure.The former generally takes the structural variable energy or quality as the minimum objective function,and the latter can be modeled by single component and the removal of other components is implemented.However,for the topology optimization of the failsafe structure of continuum structure,its objective function is defined as minimizing the structural deformation energy in the worst case of all the local failure scenarios.For the problem of the nondifferentiable objective function caused by too many local damage scenarios,this paper adopts KS aggregation function and other equivalent measures to solve the problem.For the optimization process,the establishment of the local failure model is realized by removing the material stiffness within the predefined dimensions in the structural design.However,when the design variables are constructed according to the optimization criteria,the influence of local failure of the structure needs to be considered again every iteration.Each local failure scenario of the structure needs to carry out additional balance equation solution and sensitivity calculation.Therefore,the whole process is very much calculated.In order to improve the efficiency of fail-safe structure optimization,this paper first studies the influence of the reanalysis method on the fail-safe optimization.In order to solve some limitations of the combination of the two in calculating large mathematical models,this paper then studies the number of simplified local failure scenarios.Before considering the impact of local failure scenarios,the number of local failure scenarios of the structure is simplified by using double filters,so as to improve the efficiency of optimization and stability of fail-safe structure.For a certain fail-safe topology optimization design problem,the calculation amount of fail-safe structure optimization can be reduced by 20% to 30% under the premise of ensuring the calculation accuracy by adjusting the tolerance of filter properly.