Flexural behavior, failure analysis, and optimization design of a hybrid composite Kagome honeycomb sandwich structure

A carbon fiber-reinforced composite Kagome honeycomb is a new type of structure composed of hexagonal and triangular cells, exhibiting excellent mechanical performance and application potential in the aerospace, automobile, and marine industries. This paper proposes a new hybrid composite Kagome honeycomb sandwich (HCKHS) structure formed using the interlocking method with polymethacrylimide foam sandwich structure as the ribs. The bending characteristics and failure modes were analyzed by conducting three-point bending tests. The experimental results showed excellent flexural bearing and energy absorption capability. Second, analytical models of HCKHS specimens under bending were established. The 1D, 2D, and 3D failure mechanism maps were drawn, and the size effects were analyzed. Based on the principle of minimum specific strength, combined with 3D failure mechanism maps, the optimal design point of the HCKHS structure was obtained through specific strength functions. The proposed method is also applicable to the optimization and design of other 2D composite honeycomb sandwich structures.