ABSTRACT
Linear elastic fracture mechanics ( L E F M ) , based on singular stress fields and energy release rates, has proven to be quite successful in describing fracture in brittle materials (Lawn 1993). A cohesive zone description of near-tip process zones emerged early in the development of the field (Dugdale, 1960, Barenblatt, 1962), but remained relatively unused in the treatment of brittle fracture. L E F M has also been used successfully under well-defined conditions for polymers (Williams, 1984). However, it becomes limited in its treatment for polymers that exhibit significant inelasticity, large deformations, and time-dependence. Analytical challenges make the cohesive zone approach relatively difficult to use, although it is fundamentally capable of handling these complications (Dugdale, 1960, Knauss, 1973, Schapery, 1975). Implementation of the cohesive zone approach in a computational context provides a means of analyzing previously intractable problems of materials failure in a way that connects local process zones with the macroscopic deformation. For these reasons, computational cohesive zone modeling has attracted attention for brittle & elastic-plastic materials (Xu & Needleman, 1994, Camacho & Ortiz, 1996, Tvergaard & Hutchinson, 1992, Espinosa et al., 1998, and Needleman and Rosakis, 1999). Failure in polymers, which is often accompanied by time-dependent and large deformation, presents unique challenges for computational analysis. In this chapter we present an implementation of cohesive zones as cohesive finite elements for tackling issues in modeling polymer interfacial fracture.
