Fatigue crack propagation law for wide range from very slow crack growth rate region to stable crack propagation rate region

From rate-dependent to quasi-static brittle crack propagation

On the base of many experimental results, e.g. [18], [19], [21], [12], the object of our analysis is a rate-dependent model for the propagation of a crack in brittle materials. Our goal is a mathematical study of the evolution equation in the geometries of the ’Single Edge Notch Tension’ (SENT) and of the ’Compact Tension’ (ASTM-CT). Besides existence and uniqueness, emphasis is placed on the r...

Thermal activation of fatigue crack growth: analysing the mechanisms of fatigue crack propagation in superalloys

A method for deriving apparent activation energies, Eapp, for fatigue crack growth (FCG) is presented. It is shown how these Eapp values can be used to analyse the main underlying mechanism causing the progression of the crack. The Eapp values for fatigue crack growth in air and vacuum, and with and without a dwell are obtained for a range of Ni based superalloys for turbine disc applications. ...

Fatigue crack propagation in microcapsule - toughened epoxy

The addition of liquid-filled urea-formaldehyde (UF) microcapsules to an epoxy matrix leads to significant reduction in fatigue crack growth rate and corresponding increase in fatigue life. Mode-I fatigue crack propagation is measured using a tapered doublecantilever beam (TDCB) specimen for a range of microcapsule concentrations and sizes: 0, 5, 10, and 20% by weight and 50, 180, and 460 lm di...

Stochastic modeling of fatigue crack propagation

This paper presents a stochastic model of fatigue-induced crack propagation in metallic materials. The crack growth rate predicted by the model is guaranteed to be non-negative. The model structure is built upon the underlying principle of Karhunen±Lo eve expansion and does not require solutions of stochastic di€erential equations in either Wiener integral or Itô integral setting. As such this ...

High Temperature Fatigue Crack Propagation in INCONEL718