Constant stress field measurements through thermoelasticity

In thermoelasticity both the second harmonic of the temperature fluctuations and the thermoelastic constant can be used to measure, without contact, residual stress on mechanical components. In this paper the combined effect of temperature mean level and constant stress field are analyzed, to better explain and develop a new analytical formulation of the relevant physical phenomena in this complex field of solid mechanics. Second harmonic measurements are then presented for low-yield stress materials: results show that thermoelastic stress analysis can be applied for constant stress measurement on low-yield stress aluminum alloy specimens, whereas for tested plastic materials, the measurement technique cannot be applied.