Effect of the Crack Tip Bifurcation on the Plasticity-Induced Fatigue Propagation in Metallic Materials

Abstract

This article deals with the influence of the crack path branching (at the micro level) on the plasticity-induced fatigue crack growth. With regard to this, a modeling by means of the finite element method was performed considering a cracked panel subjected to tension with different symmetric and asymmetric configurations of the bifurcated crack tip. The results show the appearance of a retardation effect in the growth rate of the bifurcated crack in relation to the growth rate of the fully straight crack in different cases studied, namely: (i) if the two branches of the bifurcation have different initial projected length, the propagation rate is greater at the crack tip corresponding to the long-branch than that of the short-branch, and the long-branch growth rate increases with the decrease of the initial branch angle and of the initial projected short-branch length and with the increase of the intensity of fatigue; (ii) if the two branches of the bifurcation have identical initial projected length, the retardation effect depends on the initial distance between the two bifurcated crack tips, the growth rate going up with the decrease of such a distance and with the increase of the fatigue intensity.

Estimation of Depth Direction of Crack by measuring the Residual Magnetic Vector Flux Density around Grains

“…They are capable of effectively resisting stress and strain and ensure safe operation of equipment by means of nondestructive testing (NDT) techniques and equipment [1,2,3,4,5,6,7]. There are a number of investigations on crack failure prediction in metallic materials using different fatigue approaches to predict failure as well as measurement by employing different techniques and scanning methods with different tools [8,9,10,11]. The studies mentioned are related to crack propagation in metallic materials, but so far, we have not seen any study that estimates the crack direction using experimental measures from the top view.…”