An enhanced beam-theory model of the asymmetric double cantilever beam (ADCB) test for composite laminates

The paper introduces a mechanical model of the asymmetric double cantilever beam (ADCB) test, usable to assess the mixed-mode interlaminar fracture toughness of composite laminates. The laminated specimen is represented as an assembly of sublaminates, each of which is modelled as an elastic beam partly connected to the other by a deformable interface, in turn considered to be a continuous distribution of elastic-brittle springs. Based on Timoshenko’s beam theory, a set of six differential equations, accompanied by suitable boundary conditions, governs the problem. By adopting the interfacial stresses as the main unknowns, the differential problem is solved analytically, and the contributions of the opening and sliding fracture modes are evaluated directly. Moreover, explicit expressions are determined for the interfacial stresses, internal forces, and displacements, as well as for the compliance, energy release rate, and mode-mixity angle. The predictions of the model are to some extent similar to those of analogous mechanical models in the literature and appear in good agreement with both numerical and experimental results.