Bioinspired architected composites with enhanced energy absorption

Inspired by the multiscale configuration of the microstructure of cork, here we create a new type of lightweight architected composite structure with a multilayered arrangement of hard brittle and soft flexible phases. The experiments show that this architected material can absorb four times of energy that of a conventional cellular structure under compressive strains up to 70%. Finite element simulations and 2D digital image correlation (DIC) were conducted to explain the failure mechanisms. It was found that this bioinspired architected composite provides a more uniform strain distribution and higher stress transfer efficiency with a progressive failure mode. Cyclic loading tests were performed to evaluate the shape recoverability. It was shown that the proposed architecture possesses exceptional shape recoverability under the compressive strain of 40%. These remarkable characteristics result from the interplay between soft and hard phase. Intrinsically, the soft phase plays an essential role in absorbing elastic energy during loading and then releasing the stored energy while unloading.