Mechanical Properties of Hierarchical Discontinuous Composites

Abstract

This work proposes bio–inspired hierarchical brick–and–mortar microstructures  where each “brick†is itself composed of smaller platelets regularly staggered in a matrix â€â€to add damage tolerance to conventionally brittle composites. Finite element simulations on such geometries are performed, using cohesive elements to model damage in the matrix; models with multiple repetitions of unit–cells are also used to evaluate damage dispersion at a macroscopic scale. Finally, hierarchical brick–and–mortar specimens are manufactured and tested, and showed good agreement with the model predictions. It is shown that optimised hierarchical brick–and–mortar architectures create a markedly non-linear material response, with extensive energy dissipation before failure, and also delay damage localisation in larger structures.