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 paper, the authors determined the stress intensity of a half-plane crack extending non-uniformly in an isotropic elastic solid subjected to general loading and the Griffith fracture criterion was applied to obtain an equation of motion for the crack tip which was consistent with the assumptions of this criterion.
Abstract: The stress intensity factor of a half-plane crack extending non-uniformly in an isotropic elastic solid subjected to general loading is determined. The loading is applied in such a way that a state of plane strain exists and that crack extension takes place in Mode I. The crack tip is initially at rest and then moves in an arbitrary way in the plane of the crack. In the process of obtaining the stress intensity factor, the complete elastic field is determined for a crack which starts from some initial position, extends at a constant rate for some time, and then suddenly stops. Once the stress intensity factor is known for arbitrary motion of the crack tip, the Griffith fracture criterion is applied to obtain an equation of motion for the crack tip which is consistent with the assumptions of this criterion. Numerical results are included for the stress intensity factor and for the velocity-dependent term in the equation of motion.
288 citations
TL;DR: In this paper, the results of experiments on three isotropic and one anisotropic materials are discussed and compared with the criteria proposed up to the present, and a new criterion is proposed, which coincides with the Gough's empirical formula for the brittle materials under combined stress.
Abstract: Fatigue crack initiates in the slip band and exists also in it near fatigue limit; many slip bands are apt to appear in the direction of the maximum shearing stress; crack propagates by the normal tensile stress; the maximum shearing stress on a plane at fatigue limit is reduced by the effect of the normal stress on the same plane. From these results of the experiment, a new criterion is proposed, which coincides with the Gough's empirical formula for the brittle materials under combined stress. As the plane of the maximum shearing stress is varied by the various combination of torsion and bending, the isotropic material should be used in the combined stress experiment. In this paper, the results of experiments on three isotropic and one anisotropic materials are discussed and compared with the criteria proposed up to the present.
287 citations
TL;DR: In this article, a scan electron microscope was used to study the growth and development of cracks in Barre granite under load, and the tensile character of stress-induced cracks and other observatios by Tapponnier and Brace were confirmed.
286 citations
TL;DR: In this paper, a simple partial crack closure model was explored to better understand the near-threshold effects observed, which led to yet better and simpler accumulative of service load damage models.
286 citations
Journal Article•
TL;DR: In this paper, a general model for normal/shear cracking in quasi-brittle materials is presented, defined in terms of the normal and shear stresses on the average plane of the crack and the corresponding relative displacements.
Abstract: A simple but general model for normal/shear cracking in quasi-brittle materials is presented. It is defined in terms of the normal and shear stresses on the average plane of the crack and the corresponding normal and shear relative displacements. A crack surface in stress space determines crack initiation under pure tension, shear-tension, or shear-compression loading. Two independent fracture energy parameters are used: the classical Mode I fracture energy and the asymptotic Mode II fracture energy under very high shear compression and no dilatancy. The cracking model proposed can be implemented in two ways: directly as constitutive law of an interface element in the context of discrete crack analysis, or as the law of a generic cracking plane in a multicrack formulation in the context of smeared crack analysis. In this paper, the first approach is presented and examples are given of numerical constitutive testing and verification with experimental data.
285 citations