“…In the past, attempts have been made to theoretically analyze the thermal stress intensity factor (SIF) (Matsunaga, et al, 1989;Goshima, et al, 1991). On the other hand, numerous papers have been published on experimental approaches to these problems using the photoelastic method (Zhang and Burger, 1985;Matsumoto, et al, 1990) and the caustic method (Wang and Hwang, 1994;Wang and Chen, 1993;Aoki, et al, 1994). However, only a few studies have focused on the effect of the crack width on the crack propagation behavior.…”