ON DETERMINING STRESS INTENSITY FACTORS FOR MIXED-MODE CRACKS FROM THERMOELASTIC DATA

An alternative methodology is presented for determining stress intensi ty factors for cracks subject to mixed-mode displacements. The methodo logy involves thermoelastic data generated from a SPATE (Stress Patter n Analysis by Thermal Emission) system and has been adapted from one u sed successfully in photoelasticity. The thermoelastic data is collect ed throughout the elastic stress held dominated by the crack tip singu larity. The stress held is described using a Fourier series within Mus khelishvili's approach. This method allows different applied stress fi elds to be described which may include transient or non-uniform stress fields. The results obtained using the new methodology are at least a s good as those obtained previously for pure mode I cases, and general ly better for mixed mode displacement conditions.