2.1.6 Composites

Composite structures, like graphite-epoxy laminates, are in general characterized by a sequence of layers with different material properties. In DIANA the family of layered shell elements [Vol. Element Library], are particularly suited for the global analysis of composite structures. The orthotropic material can be modeled with orthotropic elasticity and an orthotropic plasticity model; currently DIANA offers the Hill model and the Hoffmann model. These plasticity models only support ideal plastic behavior, hardening could be described with the fraction model [§5.1.7].

Delamination.

The delamination of composite materials can be modeled accurately via a strategy in which the layers have an orthotropic linear elastic material behavior and the interface between the layers and connected by interface elements with nonlinear behavior.