Digital Photothermoelastic and Numerical Analysis of Transient Thermal Stresses in Cracked Bimaterial Interfaces

Transient thermal stresses of a bimaterial specimen with interface cracks, under uniform cooling by convection, are analyzed by photothermoelasticity and a coupled temperature-displacement, finite element scheme. The stress intensity factors of the interface crack are determined by a multiparameter overdeterministic system of equations in a least-squares sense using the experimental data and by $J$-integral, numerically. The study showed that a normal temperature variation can lead to significant stresses due to the mismatch of thermal expansion coefficients.