STICK-SLIP IN THE THIN-FILM PEEL TEST .1. THE 90-DEGREES PEEL TEST

An analysis of the process of stick-slip in the 90-degrees peel test i s carried out using a slender-elastic-beam theory which considers both stretching and bending of the film. Using an energy-based crack propa gation criterion, it is shown that the intersection between the energy release rate curve and the interface toughness cur-ve delineates the limit cycle on the interface toughness versus crack-growth rate plane for stick-slip 90-degrees peeling. As a result of this analysis, it ha s 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 thick ness and length of the free film, and the dependence differs for the b ending-dominant and stretching-dominant peel tests.