Measurements of near-tip displacement fields, separated J integrals and separated energy release rates for interfacial cracks using phase-shifting Moire interferometry

In this paper, first, the concepts of the separated J integrals and the sep arated energy release rates, which have the physical significance of the en ergy release rates from corresponding material sides of a bimaterial are br iefly presented. Phase-shifting moire interferometry is used to investigate interfacial crack-tip behavior of a bimaterial specimen, which is fabricat ed of epoxy and aluminum. The loading angle to the interfacial crack is sys tematically changed. The inplane displacement fields near the interface cra ck are recorded by the phase-shifting moire interferometry. Using the measu red displacement fields, the stress intensity factors and the separated ene rgy release rates are evaluated. From the theoretical and experimental resu lts, it is found that the compliant material (epoxy) side provides consider ably larger fracture energy to the interfacial crack tip.