Interfacial Cracking in Thermomechanically Loaded Elastoplastic Bimaterials

Abstract

The failure analysis of thermally loaded two-phase compounds, in material science usually denoted as bimaterials, requires the determination of stress states due to applied nonstationary temperature fields as well as the consideration of the mismatch of the mechanical and thermal material constants. The structural performance of material compounds is essentially affected by existing defects of various kinds. Regarding the formation of yielding zones in ductile materials, which particularly arise in the vicinity of defects, the utilization of elastic-plastic constitutive equations is necessary. Various publications address the problem of mechanically strained interface cracks in elastic-plastic bimaterials. For the case of small scale yielding (SSY), HRR-like stress field structures have been found [1, 2]. Proceeding contributions based on the deformation theory have provided asymptotic stress fields, where the leading term of those asymptotic stress fields is parameterized by the J-integral [3, 4]. From the mechanical point of view, an energy balance in the crack tip area identifies the J-integral as a crack driving force [5, 6]. In this paper, the quantitative characterization of different self-stress states in the vicinity of an interfacial crack tip is performed by using the J-integral, where the influence of temperature gradients close to the interface crack tip is of most interest.