Genetic identification of crack-tip parameters using thermoelastic isopachics

A curve-fitting routine based on a genetic algorithm is used to generate noise-free cardioid curves from thermoelastic data obtained from the neighbourhood of a crack-tip. The technique is benchmarked using simulated thermoelastic data. The generated cardioid curves are used to determine the stress intensity factors (SIFs) from slots and real cracks loaded in mode 1 and mixed-mode. The derived SIFs show excellent agreement with theory and confirm the validity of the approach. The curve-fitting approach allows more information to be obtained from the thermoelastic data than previous analysis routines and will provide a basis for further development of thermoelastic stress analysis for application in crack-tip stress studies.