The Hardening Effect for Mode I Cracks Loaded by Forces Parallel to the Crack

The paper considers the effect of possible hardening of a sample with a crack with additional compression forces along the crack. This effect was first experimentally discovered by a group of scientists led by Z. Bažant in the study of a normal separation crack and has not yet received a proper explanation. In this paper, instead of the classical singular solution, we propose to consider a nonlocal regular solution for a normal separation crack, in which the stress components are regular and determine the stress concentration. In this case it becomes possible to assess the maximum loads using traditional strength criteria. It is shown that this approach allows modeling the Bažant effect and predicting its manifestation for various materials through the scale parameter in regular solutions.