Multi-objective optimization of a sandwich structure with a hybrid composite grid core

Abstract

This study evaluated two multi-objective optimization problems of a hybrid composite grid core sandwich structure, aiming at maximizing the critical buckling load while minimizing the structural weight or the costs of raw materials. The sandwich structure had a core with a composite isogrid pattern covered by two composite skins, and design variables included the space between core ribs, the core rotation angle, and the dimensions and materials of ribs. The stiffeners of the core were considered with I and box cross sections to investigate the cross section effect of ribs. The results showed that materials with high density and low mechanical properties are not suitable for reducing cost and weight. Geometrically, the use of cross-section and box has a significant effect on the buckling load capacity of the structure. Although two different criteria have been used to design the structure, the end results are almost the same. Moreover, the First-order Shear Deformation Plate Theory and the Ritz method were utilized to obtain the buckling load. Finally, the optimal alternative was found among the existing ones using the continuous genetic algorithm approach.