Numerical Study of the Mixed-Mode Delamination of Composite Specimens

The present research deals with the delamination process in multilayered composite specimens, with a reduced computational effort. The adhesive interface between sublaminates is represented as a continuous distribution of elastic-brittle springs in the normal and/or tangential direction depending on the interfacial mixed-mode condition. Each composite adherend, instead, is modeled according to the Timoshenko's beam theory. The proposed formulation is here enhanced through the Generalized Differential Quadrature (GDQ) method, where the differential equations of the problem are solved directly in a strong form. Thus, the possibility of tracking the delamination response of the specimens is provided locally in a numerical sense, in terms of interface stresses, internal forces and displacements, but also in terms of critical fracture energies and mode mixity angles. A further check of the proposed formulation is performed with respect to some standard solutions available in literature. The good agreement between numerical and theoretical predictions verifies the efficiency of the proposed GDQ approach for the study of complex mixed-mode delamination phenomena in composite materials and joints.