Examination of small crack normal to multiple elasticity and plasticity mismatched interfaces in residually stressed fiber metal laminate (Glare): Theoretical and numerical approaches

摘要

A small Mode I crack, normal to interfaces between elasticity and plasticity mismatched material layers, in a residually stressed aluminum-fiber laminate (Glare) is modeled under monotonic and cyclic loads. An analytical model is presented in small scale yielding or K-dominant regime that quantifies the effect of property mismatched interfaces over the crack tip in the laminate by determining energy release rate and stress intensity parameter. Cracked laminate is also modeled by finite element method. Values of energy release rate and strain energy density are obtained over cyclic paths far away from the crack tip, around the influencing interfaces, and in the vicinity of the crack tip. Numerical results are found to be close to theoretical estimations. Re-distribution of stress state in un-identical material layers during crack growth, resulting in different energy release rates of the crack in the laminate vis-a-vis those of the crack in similarly stressed homogeneous aluminum, is well substantiated. Methodology to incorporate the surface and material micro-structural effects over the crack is also proposed.