MULTI-OBJECTIVE OPTIMIZATION OF HIERARCHICAL CORRUGATED STRUCTURE UNDER FAILURE MODES CONSTRAINTS

Six failure modes may occur for hierarchical corrugated structures under compressive or shear loads, and the corresponding nominal stress of plate model were analyzed based on the theories of Euler beams and elastic plates in this study. The failure modes were designed by comparing the nominal stress, and then the multi-objective optimization was performed to minimize both weight and deflection. Two optimization formulations were established, with one controlling a special failure mode occurs first and another classifying the failure modes into two grades considering the loss degree, and then the failure mode occurs as a specific sequence. On this basis, the performance index of several typical design points from the Pareto front of two models was discussed. Finally, the failure modes were verified by FEM. The results show significant improvement of the performance for both models, and the failure modes occur as expected. The second model is safer, in which the difference of nominal stress for each failure mode is considered, in order to avoid sudden occurrence of global failure.