The mechanics of delocalization and energy absorption in chain composites

The mechanics of chain composites that can exhibit delocalized failure and very large values of energy absorbed per unit volume during failure are ana lyzed. The composites absorb energy because they are configured in such a w ay that chain links must displace through large distances before coming int o intimate contact with one another, doing work continuously against the ma trix. An approximate analytical model for the stresses within the chain lin ks during link displacement is formulated and the results validated by fini te element analyses. The condition that the maximum stress within the links be less than the link strength leads to a criterion for transition from lo calized failure (involving failure of the links at small strains) to deloca lized failure (with distributed damage and large plastic strains occurring via link displacement). The model is also proposed as a design rule for opt imizing the energy absorption of this class of composites. (C) 2000 Acta Me tallurgica Inc. Published by Elsevier Science Ltd. All rights reserved.