This paper reviews the capabilities of a plasticity-induced crack-closure model to predict fatigue lives of metallic materials using “small-crack theory” for various materials and loading conditions. Crack tip constraint factors, to account for three-dimensional stateof-stress effects, were selected to correlate large-crack growth rate data as a function of the effective-stress-intensity factor...

In-phase TMF crack growth testing with different lengths of the hold time at the maximum temperature of 550C has been conducted on Inconel 718 specimens. Focus has been on establishing a method for TMF crack growth testing and investigating the effect of high temperature hold times on the TMF crack growth of the material. The tests are compared to isothermal crack propagation tests and show go...

In this study, single-edge cracked uniaxial specimens with an initial crack length of 0.1 in or 0.3 in and wedge-shaped sheet specimens with an initial crack length of 0.3 in were tested at a constant displacement rate of 50 in/min under 1000 psi confining pressure. The specimens were made of a highly filled polymeric material, containing 86% by weight of hard particles embedded in a rubbery ma...

A model has been created to allow the quantitative estimation of the fatigue crack growth rate in steels as a function of mechanical properties, test–specimen characteristics, stress–intensity range and test–frequency. With this design, the remarkable result is that the method which is based on steels, can be used without modification, and without any prior fatigue test, to estimate the crack g...

In this study, in order to investigate crack retardation behavior and the variability of retardation cycles, crack growth tests are conducted on 7075-T6 aluminum alloy under a single tensile overload. A retardation coefficient D is introduced herein as the ratio of the crack growth rate under constant amplitude loading and the crack growth rate after an overload. This coefficient D is separatel...

Fatigue crack growth (FCG) research conducted in the near threshold regime has identified a room temperature creep crack growth damage mechanism for a fine grain powder metallurgy (PM) aluminum alloy (8009). At very low ∆K, an abrupt acceleration in room temperature FCG rate occurs at high stress ratio (R = Kmin/Kmax). The near threshold accelerated FCG rates are exacerbated by increased levels...

The crack growth properties of several sealing glasses were measured by using constant stress rate testing in 2% and 95% RH (relative humidity). Crack growth parameters measured in high humidity are systematically smaller (n and B) than those measured in low humidity, and crack velocities for dry environments are 100 lower than for wet environments. The crack velocity is very sensitivity to sma...

This paper presents a new incremental formulation for predicting the curved growth paths of twodimensional fatigue cracks. The displacement and traction boundary integral equations (BIEs) are employed to calculate responses of a linear elastic cracked body. The Paris law and the principle of local symmetry are adopted for defining the growth rate and direction of a fatigue crack, respectively. ...