Numerical evaluation of interface fracture parameters using adina

The problem of cracking at interfaces is pertinent not only to composite materials but also to structures with adhesive joints, thin films and coatings. Criteria are needed for the study of the crack growth scenarios in the interfacial region where relative magnitudes of the fracture energy for the constitutent materials and that of the interface play an important role in cracking behavior. Interface fracture occurs when the interfacial energy release rate G is equal to the interfacial fracture energy Γ_i, that is characterized as a function of the loading phase ψ. Therefore, for the analysis of interfacial fracture both the energy release rate (G) and the loading phase angle (ψ) must be evaluated. In this paper, a numerical method is presented to obtain the values of these two parameters at the tip of an existing interface crack. Numerical analyses of three models containing interface cracks are performed using the ADINA finite element program. In general, good agreement between the results from the numerical calculation and the analytical solutions is obtained.