Rotational interface formulation for delamination analysis of composite laminates

In this paper, delamination progression in a composite laminate is modelled by interface elements within a geometrically non-linear FE analysis setting. With the assumption of small continuum deformations, a rotational interface formulation is obtained from a recently proposed formulation based on the concept of a regularised strong discontinuity, cf. [Int. J. Numer. Meth. Eng. 54 (2002) 473]. The degradation of the stress vector in the cohesive zone is described by a damage-plasticity coupling, which is calibrated analytically against experimental data of mixed-mode fracture energies. The paper is concluded by a couple of numerical examples that describe the predictive capabilities of the interface formulation.