Decoupling toughness and strength through architected plasticity

Abstract

We investigate the elastic–plastic fracture of architected materials through experiments and theory, with a focus on understanding the combined effects of material length scale and geometry, using a pillar array as a model structure. We show that load sharing across the pillars, and hence toughness, can be controlled by changing the spatial distribution and height of the pillars. A simple relation is presented to relate the extent of the plastic fracture process zone to the pillar array structure and the resulting toughness. This relation allows for quantitative prediction of failure loads of specimens with plasticity localized to a structured region and reveals that strength and toughness can be decoupled through architecture. Our findings establish a foundation for design of architected materials with enhanced fracture toughness.