Delamination from edge flaws

Abstract

The mechanics of delamination from an edge flaw in a laminated material is presented. Two different types of failure mechanism have been identified: uniform delamination along the crack front and localized delamination which can be initiated if the laminate buckles above the debonded portion of the interface. Depending on the stress state within the bonded portion of the laminate, this localized failure can initiate the formation of blisters which grow by a mechanism of buckling-driven delamination and can cause general failure of the laminate. There are conditions under which this class of buckling-assisted delamination occurs at loads lower than would be predicted for uniform delamination. It may, therefore, have important implications in the design against failure for thin films, composites and other laminated systems. Experimental observations of the different failure mechanisms are presented and the factors governing the transitions between them are discussed.