Topic
Crack closure
About: Crack closure is a research topic. Over the lifetime, 28157 publications have been published within this topic receiving 588158 citations.
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TL;DR: In this article, a philosophy of employing computational simulation to establish relations between remote loading conditions and microstructure-scale slip behavior in terms of Fatigue Indicator Parameters (FIPs) as a function of stress amplitude, stress state and micro-structure, featuring calibration of mean experimental responses for known microstructures.
128 citations
TL;DR: In this article, a simple crack growth rate equation has been proposed, which can condense the crack growth data under different R -ratios to the curve corresponding to R ǫ = 0.
128 citations
TL;DR: In this article, the authors present an alternative, simpler quadratic equation to evaluate mode mixity of interfacial fracture utilizing the virtual crack closure technique (VCCT), and they show that when the reference length and the normalizing length are equal, the two mode mixities are only shifted by a phase angle, depending on the bimaterial parameter e.g.
Abstract: We review, unify and extend work pertaining to evaluating mode mixity of interfacial fracture utilizing the virtual crack closure technique (VCCT). From the VCCT, components of the strain energy release rate (SERR) are obtained using the forces and displacements near the crack tip corresponding to the opening and sliding contributions. Unfortunately, these components depend on the crack extension size, Δ, used in the VCCT. It follows that a mode mixity based upon these components also will depend on the crack extension size. However, the components of the strain energy release rate can be used for determining the complex stress intensity factors (SIFs) and the associated mode mixity. In this study, we show that several—seemingly different—suggested methods presented in the literature used to obtain mode mixity based on the stress intensity factors are indeed identical. We also present an alternative, simpler quadratic equation to this end. Moreover, a Δ-independent strain energy release based mode mixity can be defined by introducing a “normalizing length parameter.” We show that when the reference length (used for the SIF-based mode mixity) and the normalizing length (used for Δ-independent SERR-based mode mixity) are equal, the two mode mixities are only shifted by a phase angle, depending on the bimaterial parameter e.
128 citations
TL;DR: In this paper, the authors investigated the fretting fatigue crack initiation behavior of titanium alloy, Ti-6Al-4V, and evaluated the ability of two critical plane approaches, Smith-Watson-Topper critical plane and maximum shear stress range critical plane, to predict the number of cycles to crack initiation, crack location and angle of crack orientation.
128 citations
TL;DR: In this article, the authors apply the method developed by Rice [1] to solve the elasticity problems of somewhat circular planar tensile cracks under arbitrary load distributions, based on a known solution for the stress intensity factor along a circular crack due to a pair of wedgeopening point forces on its surfaces.
Abstract: In this paper we apply the method developed by Rice [1], of solving for the elastic field of a crack with a front perturbed from some reference shape, to solve the elasticity problems of somewhat circular planar tensile cracks under arbitrary load distributions. The method is based on a known solution for the stress intensity factor along a circular crack due to a pair of wedge-opening point forces on its surfaces. A full solution, accurate to first order in the deviation from a circular shape, is derived for the stress intensity factor and the crack opening displacement distributions. The results of a perturbation in a harmonic wave form suggest that a circular crack, under axially symmetric loading, can be configurationally unstable (not grow as a circle) for loadings that increase in intensity with distance from the center. Circular cracks with harmonic shape perturbations are found to have the same form of variation of the stress intensity factor with arc length along the crack edge (to first order accuracy) as found in previous work for a half plane crack. As a test case for the perturbation solution, an elliptical planar tensile crack under uniform tension is viewed as being perturbed from a circular crack. Results derived from the perturbation formulae through numerical evaluation are compared with the exact solutions existing in the literature. The perturbation results show a very good match with the exact solutions even when the semi-axis lengths of the elliptical crack differ by a factor of two (and by as much as a factor of three when special choices of the reference circular crack location are made). This suggests that the perturbation procedure presented here, while theoretically exact only to first order, can be used to produce acceptable results for some planar cracks whose shapes deviate appreciably from a circle.
128 citations