Analytical and experimental methods for a fracture mechanics interpretation of the microbond test including the effects of friction and thermal stresses

An energy release rate model based on a generalized fracture mechanics of composites was developed for analyzing the microbond test. This model, which extended a previous model, includes both friction at the fiber/matrix interface and residual thermal stresses. A series of microbond tests on macroscopic specimens were carried out for evaluating the model. In some specimens we could observe debond crack growth. These results could be interpreted with a fracture mechanics R-curve which led to a measured interfacial fracture toughness. In many specimens, debond crack growth could not be observed. We developed an approximate method for determining interfacial fracture toughness even without knowledge of debond crack size. The macroscopic specimens were designed for studying the optimal approach to analysis of microbond specimens. The geometry of the macroscopic specimens, however, could also be used to measure the mode II toughness of adhesive bonds. (C) 1999 Elsevier Science Ltd. All rights reserved.