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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 paper, an analysis is presented which enables crack propagation rates under cyclic loading condiditions to be predicted from static slow crack growth parameters, and a comparison of the predicted times to failure under static and cyclic conditions with available measured failure times, for several ceramic materials at ambient temperatures, suggests that there is no significant enhancement of the slow-crack growth rate due to cycling.
Abstract: An analysis is presented which enables crack propagation rates under cyclic loading condiditions to be predicted from static slow crack growth parameters. A comparison of the predicted times to failure under cyclic conditions with available measured failure times, for several ceramic materials at ambient temperatures, suggests that there is no significant enhancement of the slow crack growth rate due to cycling. This is verified in a series of measurements of slow crack growth rates under static and cyclic conditions.

213 citations

Journal ArticleDOI
TL;DR: In this paper, a subcritical fracture growth model is used to generate equilibrium crack geometries, where fracture length distributions and spacing are modeled as proportional to the n-th power of the mode I stress intensity.
Abstract: Fracture networks are examined in the light of subcritical crack growth theory. Examples of equilibrium crack geometries are generated using a fracture mechanics model that explicitly tracks the propagation of multiple fractures. It is determined that propagation velocity as modeled using a subcritical fracture growth law exerts a controlling influence on fracture length distributions and spacing. Velocity is modeled as proportional to the n-th power of the mode I stress intensity. Numerous, closely spaced, similar length fractures result for n=1, with many en echelon arrays forming due to fracture interaction. Increasing the value of n results in the growth of fewer fractures that are more widely spaced. Fractures tend to cluster in narrow zones, with limited fracture growth in the intervening areas. The spacing between zones is controlled by the stress shielding effects of longer fractures on shorter ones. The amount of time required for fracture pattern development is also influenced by the subcritical velocity exponent, n. At low n, patterns take seconds to minutes to develop, while patterns generated at higher n can require hundreds of years or more.

213 citations

Journal ArticleDOI
TL;DR: For a viscoelastic modulus E (omega) which increases as omega(1-s) (0< s< 1) in the transition region between the rubbery region and the glassy region, it is found that a (v) approximately G ( v) approximately v(alpha) with alpha= (1- s) / (2-s).
Abstract: We study crack propagation in a viscoelastic solid. Using simple arguments, we derive equations for the velocity dependence of the crack-tip radius, a (v) , and for the energy per unit area to propagate the crack, G (v) . For a viscoelastic modulus E (omega) which increases as omega(1-s) (0< s< 1) in the transition region between the rubbery region and the glassy region, we find that a (v) approximately G (v) approximately v(alpha) with alpha= (1-s) / (2-s) . The theory is in good agreement with experiment.

213 citations

Journal ArticleDOI
TL;DR: In this article, the authors derived the crack propagation law from the S-N data in the very high cycle fatigue of a bearing steel and divided the cracks into stages I and II.
Abstract: The crack propagation law was derived from the S-N data in the very high cycle fatigue of a bearing steel. The propagation rate, da/dN (m/cycle), of surface cracks was estimated to be a power function of the stress intensity range, ΔK (MPa√m) with the coefficient C s = 5.87 x 10- 13 and the exponent m s = 4.78. The threshold stress intensity range was 2.6MPa√m. The crack propagation from internal inclusions was divided into Stages I and II. For Stage I, the coefficient of the power law was C o = 3.44 x 10 -21 and the exponent m o = 14.2. The transition from Stage I to II took place at ΔK = 4.0 MPa√m. For Stage II, the coefficient was C i = 2.08 x 10 -14 and the exponent m i = 4.78. The specimen size and loading mode did not influence the surface fatigue life, while the internal fatigue life was shortened in larger specimens and under tension-compression loading. For ground specimens, the surface fatigue life was raised by the compressive residual stress, while reduced by the surface roughness introduced by grinding. For shot-peened specimens, fatigue fracture did not take place from the surface because of a high surface compressive residual stress. The internal fatigue life was reduced by the tensile residual stress existing in the interior of the specimens.

212 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023219
2022536
2021143
2020154
2019172
2018244