Analytical and numerical calculation of the energy release rate for the Microbond-Test

The energy release rate for interface crack propagation for the Microbond-T est specimen is calculated by using several stress analysis methods. For th e corresponding finite element calculation an axisymmetrical model (ellipti cal droplet) and linear elastic material properties are used. The analytica l approximations use several stress analysis methods to obtain the energy r elease rate. The resulting energy release rate curves suggest that the debonding process can be described at least partially as a stable crack propagation along th e interface. Some experiments confirm this prediction. The matrix droplet c ontribution to the energy release rate can be considerable. Because of the very complex stress fields in the droplet a simple analytical approximation cannot be given. The qualitative dependences on the material properties an d on the geometry can be explained from the presented analysis. The remaini ng correction factor can be obtained from a numerical calculation.