Bažant-Le-Kirane Paradox of Fatigue Fracture

Abstract

The study of fracture process zone (FPZ) is critical to understanding failure in engineering materials. Experiments conducted by Le et al. [1] on Berea sandstone found that the size of the fracture process zone under cyclic loading (cyclic FPZ) is 1.6 times larger than that under monotonic loading (monotonic FPZ). Experiments and simulations conducted by Kirane and Bažant [2] on concrete found that the cyclic FPZ is eight times smaller than the monotonic FPZ. Both these materials exhibit contrasting responses. This interesting contradiction is named the "Bažant-Le-Kirane Paradox" (B-LK Paradox) after the principal authors of these two papers. The B-L-K paradox is a significant problem in the fracture and fatigue mechanics. We also present strategies to resolve this paradox