Shape Optimization of H-Beam Flange for Maximum Plastic Energy Dissipation

The purpose of this paper is to show that the performance of a structural component is drastically improved utilizing shape optimization considering inelastic responses. Optimal flange shapes are found as an example for an H-beam to show that the energy dissipation capacity is significantly improved by shape optimization. The forced displacement is given at the free end of the cantilever beam so that the average deformation angle reaches the specified value. The constraint is given for the maximum equivalent plastic strain at the welded section. Global optimal solutions are searched by a heuristic approach called simulated annealing, which is successfully combined with a commercial finite-element analysis code ABAQUS for elastoplastic analysis. It is shown in the examples that the maximum plastic strains near the welded section are reduced and the plastic deformation is widely distributed around the reduced section of the optimal solution; thus, allowing large energy dissipation under small maximum plastic strain. The results show the advantage of the optimal shape over the conventional circular cut.