Interface cracks in layered materials subjected to a uniform temperature change

摘要

Elastic and incremental elasto-plastic analyses have been used to evaluate the driving force for interface edge-crack growth initiation in tri-layered material systems subjected to a monotonic variation in temperature. Whenever possible, closed-form solutions are derived as functions of the thermo-mechanical material properties and the geometry of the layers. Analytical expressions for the different critical temperatures at which distinct transitions occur in thermally induced deformation are presented and are correlated with the three regimes of interface fracture; elastic, partially plastic and fully plastic. Furthermore, a large-scale contact model, which predicts the shielding effect of contact in the wake of an interface crack, is also presented and the attendant reduction in the energy release rate is estimated. Finite element results, showing the influence of layer geometry and strain hardening on the energy release rate, are presented for a model Al_2O_3/Ni(Cr)/Al_2O_3 tri-layered system; these simulations confirm the bounds predicted by the theory.