Study on Mechanism of Decrease/Disappearance of Threshold Stress Intensity Range

Abstract

In the past decade, threshold stress intensity factor range : △K_<th> obtained by K_<max> = const. method, has become to be recognized as the intrinsic △K_<th>. However, some up-to-date show that when K_<max> becomes large, threshold will decrease or disappear. We therefore made K_<max> = const △K_<th> test with mild steel S55C as a first step, and made a study on the mechanism of this decrease.