Delamination analysis in bimaterials consisting of shape memory alloy and elastoplastic layers

摘要

Bimetallic shape memory alloy composites, consisting of an active layer of shape memory alloy and a metallic elastoplastic passive layer, are used for designing the sensors and actuators. Delamination analysis in SMA/elastoplastic bimaterial composites is numerically investigated in this study due to the important effects of interface cracks on failure and load bearing response of such composites. It is known that homogeneous elastoplastic material and shape memory alloy show different path-dependent behaviors for prediction of energy release rate near the crack tip. Therefore, evaluation of J-integral for an interface crack between SMA and elastoplastic layers remains a highly complex issue in fracture analysis of such bimaterials. Presuming small-scale phase transformation and yielding zones, path dependency of J-integral for this composite is investigated for a range of mixed-mode loading conditions, and the elastoplastic material properties including the Young's modulus, hardening slope and yield stress. In addition, the maximum transformation strain within the framework of J(2) plasticity for the elastoplastic material and the thermo-mechanical coupling model of Boyd and Lagoudas for the shape memory alloy are studied. Finally, the influence of mixed-mode loading rates on the crack tip fields is comprehensively assessed.