Stick-slip in the thin film peel test—I. the 90° peel test

An analysis of the process of stick-slip in the 90° peel test is carried out using a slender- elastic-beam theory which considers both stretching and bending of the film. Using an energy-based crack propagation criterion, it is shown that the intersection between the energy release rate curve and the interface toughness curve delineates the limit cycle on the interface toughness versus crack-growth rate plane for stick-slip 90° peeling. As a result of this analysis, it has been found that the effects of bending are significant and cannot be neglected in the general case. In addition, the stick-slip period and frequency have been found to depend on Young's modulus, and the thickness and length of the free film, and the dependence differs for the bending-dominant and stretching-dominant peel tests.