Retardo en la propagación por fatiga inducida por plasticidad debido a la deflexión del extremo de fisura

Abstract

This article studies the retardation effect in plasticity-induced fatigue crack growth rate for a low-medium strength steel due to the appearance of micro-deflections in the crack path. To this end, the finite element method (FEM) was used to model the crack with its kinked tip (for several initial angle and initial projected length) in a plate under several stress intensity factor (SIF) ranges. The results allowed to calculate the ratio between the fatigue crack propagation rate for the crack deflected (multiaxial fatigue behaviour at the microscopic level) and for the totally straight crack (uniaxial fatigue), obtaining that the retardation effect increases with the initial kinked crack tip angle and its initial projected kinked crack tip length, as well as with the decrease of the SIF range.