Analysis of damage localization in composite laminates using a discrete damage model.

Abstract

Damage localization around stress raisers and material defects in laminated composites is studied using adiscrete damage mechanics model augmented by a fiber damage model. The proposed formulationcaptures the damaging behavior of plates with initial defects and stress raisers such as holes, including damage initiation, evolution, and ultimate fracture of the specimen. It also helps explain the reductionof stress concentration factor when matrix and fiber damage develop. The state variables are the crack density and the fiber failure damage. The formulation is implemented as a material model in Abaqusapplicable to laminated composite plates and shells. Material defects are simulated by inserting an initialcrack density in a small region of the specimen. Stress raisers are simulated by an open hole. The predictions are shown to be insensitive to mesh density. Further, damage localizes near stress raiserand material defects, thus numerically demonstrating the objectivity of the proposed model. Qualitative and quantitative comparisons with experimental data are presented.