Analytical and Numerical Calculation of the Energy Release Rate for the Microbond-Test

The energy release rate for interface crack propagation for the Microbond-Test specimen is calculated by using several stress analysis methods. For the corresponding finite element calculation an axisymmetrical model (elliptical droplet) and linear elastic material properties are used. The analytical approximations use several stress analysis methods to obtain the energy release rate.

The resulting energy release rate curves suggest that the debonding process can be described at least partially as a stable crack propagation along the interface. Some experiments confirm this prediction. The matrix droplet contribution 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 and on the geometry can be explained from the presented analysis. The remaining correction factor can be obtained from a numerical calculation.