New weight filtering factor of nonlinear design for topology optimization under cyclic loading based on proportional technique

The structure should be focusing on the nonlinear behavior when an external load is applied and causes a large deformation. This research presents the topology optimization under bilinear elastoplastic and isotropic and kinematic hardening material properties. Optimization is performed using the solid isotropic material with penalization approach, and each element density is updated based on a proportional technique. The proportional technique is a non-sensitivity method proposed by combining with the fully stressed criterion for the topology optimization to be one factor of the update function. The cyclic load was applied to the structure and indicated an effect of stress fluctuation through the optimization process. Numerical examples were examined to investigate the final layout based on the nonlinear material properties under a nonlinear analysis. Finally, a new filtering density equation was proposed to avoid stress fluctuation during the optimization process. The optimal layout was clearly obtained while investigating the cyclic load effect.