Free-Edge Stress Intensity Factor for a Bonded Ductile Layer Subjected to Shear

The stress state found in a thin, power-law hardening ductile layer bonded between a pair of rigid adherends and subjected to a shear loading is investigated. Within the context of a work-hardening plasticity theory, a stress singularity of type Kr^δ (δ < 0) exists at the point where the interface between one of the rigid adherends and the ductile layer intersects the stress-free edge. The intensity of this singularity (i.e., K) has been calculated for a plane strain condition using a technique that combines results of an asymptotic analysis of the stress singularity with those of a detailed finite element analysis. A dead-soft aluminum layer is considered first with emphasis placed on an assessment of the region dominated by the plastic stress singularity. Results for a fully plastic layer with negligible elastic strains are presented next. The relation defining the fully plastic, free-edge stress intensity factor for a shear loading depends only on a characteristic shear stress, layer thickness, and the layer’s hardening exponent.