Explicit modeling of matrix cracking and delamination in laminated composites with discontinuous solid-shell elements

Abstract

Composite structural failure usually entails complicated interactions between intralaminar and interlaminar damage. In this paper, a novel discontinuous solid-shell finite element combined with a 3D enriched cohesive element is formulated for the analysis of matrix cracking and delamination in multilayered composites. The proposed formulations are computationally attractive in modeling thin shell structures while retaining the advantages of solid elements. The bending performance was improved by using the enhanced assumed strain method and the assumed natural strain method, which alleviates potential locking problems. A linear elastic orthotropic law was used for layered shells and cracks therein were modeled with a cohesive zone model. A discrete crack method with floating nodes enriching the developed elements enables a mesh-independent description of ply cracks and their interaction with interface cracks. The applicability of the current formulation was verified with numerical examples including large deformations of thin shell problems and delamination growth in post-buckled laminates. Finally, the explicit and totally discrete modeling of matrix and delamination cracks in low velocity impact of cross-ply and angle-ply laminates was demonstrated. Numerical predictions of structural responses and damage patterns agree well with experimental results.