Variable amplitude fatigue crack growth behavior — a short overview

Abstract

A short overview concerning variable amplitude (VA) fatigue crack growth behavior is presented in this paper. The topics covered in this review encompass important issues pertaining to both single and repeated overload transients. Reviews on transient post overload effects such as plasticity induced crack closure, crack tip blunting, residual stresses, crack deflection and branching, activation of near threshold mechanisms, strain hardening are highlighted. A brief summary on experimental trends and finite element modelling of overload induced crack closure is also presented.

Influence of complex LCF and dwell load regimes on fatigue of Ti–6Al–4V

“…However, blunt-400 ing was seen to slow crack propagation only at high overloads. An effect from increased surface irregularities contributing to roughness-induced crack closure has also been observed in literature [28]. In the present case this seems unlikely, since no increased roughness was seen during SEM observations.…”

“…This then causes improved closure at the crack tip, reducing the growth speed. Also discussed in the literature is the possible blunting of the crack by overloads [28]. The initial sharp crack after a 880 MPa cycle could have blunted after the 940 MPa cycles, reducing the stress concentration and hence slowing the crack.…”

Advanced Methods of Fatigue Assessment

“…For identical load histograms, crack growth life under random loading is shorter than under blocked loading. A variety of data is gathered in another overview (Singh et al 2011). In blocked loading, a descending sequence produces longer lives than an ascending sequence, Fig.…”

Crack simulation models in variable amplitude loading - a review

“…3 presents an adapted chronologic review crack advance scheme from Matos & Nowell [63]. In Singh et al [80] the authors provide a review of some crack propagation issues. The paper cover the transients and single overload effects as well as the plasticity induced crack closure.…”

“…The paper cover the transients and single overload effects as well as the plasticity induced crack closure. In this topic Singh et al [80] presented a discussion regarding how the researchers normally work in crack propagation simulation considering overload-induced crack closure. Lei [81] determine the crack closure by finite element method in a compact specimen.…”