Study of three‐point bending behaviors of composite sandwich structure with re‐entrant honeycomb cores

Abstract The composite re‐entrant honeycomb structures were fabricated by hot pressing and bonding processes in this article. The bending responses of composite re‐entrant honeycomb structure under three‐point bending load were studied experimentally. The bending deformation, failure process and failure load were analyzed and discussed. The influence of wall thickness gradient form which were less reported on the bending behaviors of composite re‐entrant honeycomb structures was investigated. The gradient distributions included positive gradient, negative gradient and homogeneous structures. The experimental results indicated that the wall thickness gradient design influenced the bending failure modes of composite re‐entrant honeycomb structures, and the negative gradient honeycomb structure mainly exhibited the whole bending deformation under three‐point bending loading. The influence of the relative densities on the bending behaviors of composite re‐entrant honeycomb structures was also studied. The results of three‐point bending experiment showed that the bending failure load increased significantly with the increase of relative density.