NUMERICAL EVALUATION OF INTERFACE FRACTURE PARAMETERS USING ADINA

The problem of cracking at interfaces is pertinent not only to composi te materials but also to structures with adhesive joints, thin films a nd coatings. Criteria are needed for the study of the crack growth sce narios in the interfacial region where relative magnitudes of the frac ture energy for the constitutent materials and that of the interface p lay an important role in cracking behavior. Interface fracture occurs when the interfacial energy release rate G is equal to the interfacial fracture energy GAMMA(i), that is characterized as a function of the loading phase psi. Therefore, for the analysis of interfacial fracture both the energy release rate (G) and the loading phase angle (psi) mu st be evaluated. In this paper, a numerical method is presented to obt ain the values of these two parameters at the tip of an existing inter face crack. Numerical analyses of three models containing interface cr acks 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.