A robust staggered localizing gradient enhanced isotropic damage model for failure prediction in heterogeneous materials

Abstract

In the present work, a robust and efficient staggered localizing gradient damage model (LGDM) with a simple isotropic damage variable is adopted to predict crack growth phenomena in bi-material and fiber reinforced composites under mixed-mode loading. We first consider a series of three-point bend experiments conducted by Lee and Krishnaswamy (2000) on bi-material specimens of PMMA/Al6061, where the staggered LGDM is shown to capture correct crack profiles under different boundary conditions. It is observed that the numerical crack paths are well compared with the experimental crack paths. Next, a fiber reinforced composite with a central fiber is considered where the effect of change in fiber sizes on the overall structural responses is investigated. It is seen that the increasing fiber size results in reduced load carrying capacity of fiber reinforced composites. Finally, we consider a fiber reinforced composite with fibers located on opposite edges of the specimen. Here, a parametric study on the strength ratio of the matrix phase is conducted to investigate their effect on crack initiation, propagation, and orientation. These simulations highlight the predictive capability of the present model in terms of structural responses as well as sharp crack profiles.