Abstract
In this paper, the digital caustic technique was used to determine the transient thermal stress intensity factors (SIFs) of edge-cracked semi-infinite plates subjected to a sudden temperature change on the plate edge. Effects of different crack lengths and orientations on SIFs were studied. By using the self-developed image processing software on a locally supported digital caustic system, caustic patterns were analyzed and SIFs were then obtained. The correlation expressions between the variations of transient thermal SIFs with the time, temperature difference and geometrical parameters of the cracks were obtained by a regression procedure.