A temperature correction methodology for quantitative thermoelastic stress analysis and damage assessment

Abstract

In thermoelastic stress analysis, an infrared detector is used to obtain the small temperature change resulting from the thermoelastic effect. The output from the detector, known as the thermoelastic signal, is dependent on both the surface stresses and the surface temperature of the component under investigation. For quantitative thermoelastic stress analysis, it is important that the response resulting from changes in the surface temperature is decoupled from the response resulting from the stress changes. In this paper, a means of decoupling the response is presented that involves making corrections for increases in surface temperature so that the thermoelastic signal is dependent only on the stresses. The underlying theory is presented and a correction factor is developed using an experimental approach. A methodology for applying the correction factor to full-field data is provided. The methodology is validated through a number of case studies and applied to a composite component subject to fatigue damage initiated at a central hole.