Axisymmetric edge debonding in patched plates

The problem of edge debonding in patched elastic plates is considered for a variety of axisymmetric loading and support conditions. The problems are approached from a unified point of view, as a moving interior boundaries problem in the calculus of variations, incorporating a Griffith type energy criterion for debonding. This results in a selfconsistent model for the intact and debonded portions of the composite structure as well as for the primitive structures which comprise the system, and in addition yields the conditions which define equilibrium configurations of a propagating contact zone boundary and a propagating bond zone boundary. The latter yields the corresponding energy release rates for debonding. The situation of edge contact is also considered. Analytical solutions to the set of problems of interest are presented. Extensive numerical simulations based on these solutions are presented and yield results in the form of threshold curves which characterize the behavior of the evolving composite structure under load. 0 1997 Elsevier Science Ltd. 1