Abstract
As is well known, peculiar stress fields caused by surface flaws are exposed on the surface of engineering materials under working loads. Few studies applying thermoelastic effects whose thermograms are closely related to the isopachics on the surface have been made to estimate various surface flaws through nondestructive testing, although these effects are generally employed in stress analysis of engineering structures. The authors have extended the thermoelastic techniques, therefore, to find nondestructively semielliptical surface cracks with various axial ratios and inclination angles to the tensile axis, and have analyzed the isopachics over the surface using a finite element method for comparison with the thermal image. As a result of these studies, it has been verified that the dimensions of the surface cracks were successfully estimated through the temperature profiles of the thermograms.
