Simulation of delamination in stringer stiffened fiber-reinforced composite shells

Fiber-reinforced composites are often used for high performance lightweight structures. For an enhanced exploitation of material reserves, fracture mechanisms should be taken into consideration. In this work, delamination and skin–stringer separation are examined in the framework of the finite element method. A cohesive interface element is used which is written in stress–strain relationships. The cohesive law rests upon a Smith–Ferrante type free energy function. It is edited so that only tensile normal or shear stresses provoke damage and contact is accounted for by an additional penalty term. Some numerical examples show the applicability of the proposed model.