Laminate damage model for composite structures

A continuum damage model for the prediction of the nonlinear response and the collapse of laminated composite structures is proposed. During laminate hardening the material model considers fiber rotation, plastic strain accumulation and inter-fiber damage to provide accurate ply stress information even at large deformations. In contrast to current continuum damage models for fiber reinforced composites, softening is defined on laminate-level instead of ply-level. Once ultimate failure is predicted, the stiffness of the whole laminate is linearly degraded in consideration of the fracture angle and the energy dissipation. This allows to use the model in combination with layered elements, and thereby its application on structural components. The presented model is validated against open-hole tension tests with different hole-diameters and shows excellent correlation and mesh-size independency. Moreover, sensible extensions of the presented model and further investigations are discussed.