Abstract
We analyze the stress field near an interface edge of an elastic-creep bi-material with and without an additional constraint layer by finite element method. The focus is on the effect of material thickness on the stress field. The results reveal that the creep J-integral, J*, on a path in a creep zone near the interface edge, which characterizes the intensity of the singular stress field, time-dependently decreases and becomes constant in the large-scale creep condition. For thin creep materials, J* increases proportionally with an increase of the thickness, while it saturates when the thickness becomes about a quarter of the material width. The normalized creep J-integral by the creep material thickness is the general parameter of the stress intensity near the interface edge for the thin films. In unconstrained bi-material, the time to reach the steady state is independent of creep material thickness; however, the one in constrained bi-material increases as the thickness decreases.
