Stress monitoring and analysis using lock-in thermography

An advanced non-destructive evaluation technique based on a thermal method and lock-in principles, known as thermoelastic stress analysis (TSA), is proposed for accurate stress measurements. Traditionally, strain gauges mounted on components of interest are used to measure stresses indirectly. In this paper, we describe the application of a thermoelastic stress analysis technique to a carbon-epoxy composite sample under dynamic loading to measure stresses. The advantages of this technique over strain gauges are described. The paper also describes methods for mapping of TSA results on CAD models and comparing the stresses with results obtained through finite element modelling.