Meso-mechanically motivated modeling of layered fiber reinforced composites accounting for delamination

Carbon fiber reinforced plastics are mostly used in laminates, which consist of several very thin layers stacked over each other. In this work, these layers are composed of either unidirectional fibers or textile reinforcements embedded in an epoxy resin. To model the orthotropic material behavior of such layers, a meso-mechanically motivated material model is used, which is based on structural tensors which represent the fiber orientations. This fully three-dimensional material model is incorporated into a solid-shell finite element, which is particularly suited for application to thin shell-like structures, because all occurring locking phenomena are cured by implementing both the EAS and the ANS concept in combination with a new concept of reduced integration with hourglass stabilization. The latter leads to high computational efficiency, still representing satisfactorily the through-the-thickness stress distribution, since the number of integration points in thickness direction can be chosen arbitrarily. Furthermore, in the presented cases, delamination is one of the most important failure mechanisms and thus needs to be considered. This is done by combining a cohesive zone-like continuum damage model with the solid-shell element formulation, which covers the interaction of different failure modes.