Theory of dynamic mode-II interfacial fracture in end-notched flexure tests

The dynamic mode-II energy release rate (ERR) of the end-notched flexure (ENF) test with applied time-dependent displacement is derived with consideration of structural vibration. The dynamic effect and the relative dynamic contribution from each vibration mode were investigated by a dynamic factor and a spatial factor. It is found that the contribution of the ith vibration mode is dependent on the spatial factor as a function delamination ratio. In addition, for a given spatial factor, there may be a certain vibration mode, which makes zero contribution to the ERR. The developed theory is verified against results from finite-element method (FEM) simulation for two cases and they are in excellent agreement.