Topic
Hydrostatic stress
About: Hydrostatic stress is a research topic. Over the lifetime, 1568 publications have been published within this topic receiving 37773 citations.
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22 Jul 2010
1 citations
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TL;DR: In this article, the effect of internal crack pressure and external stresses on gas permeability of coal has been investigated and the relation between the gas permeation rate and the differential pressure has been determined from Darcy's law.
Abstract: In this study the special tests of gas permeability of coal have been conducted in order to make clear the effect of internal crack pressure and external stresses on gas permeability of coal. Practically, gas permeation rate has been measured by changing the differential pressure as a parameter under a constant mean pressure and a constant hydrostatic stress.As the results of these tests, the relation between the gas permeation rate and the differential pressure had the linearity determined from Darcy's law. The gas permeability of coal decreased almost exponentially in response of an increase of the internal mean pressure and the external hydrostatic stress. From these considerations it became clear that the gas permeable cracks closed corresponding to the effective stress. Particularly, hydrostatic stress closed the permeable cracks irreversibly.
1 citations
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1 citations
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31 Mar 2020TL;DR: In this article, the authors highlight the plastic strain distribution in the deformed material as a function of the hydrostatic pressure, the torsion angle and the temperature of the material applied during the process.
Abstract: High Pressure Torsion (HPT) is a highly effective super-plastic deformation process for obtaining nano-materials with high performance mechanical properties. In view of its optimization, it is of paramount importance to evaluate the relations between the behavior of the material under the effects of different processing parameters. In this context, this work aims to highlight the plastic strain distribution in the deformed material as a function of the hydrostatic pressure, the torsion angle and the temperature of the material applied during the process. A typical amorphous polymer (Polymethyl-Methacrylate: PMMA) has been tested. Firstly, in order to identify the material parameters of a phenomenological elasto-viscoplastic model compression tests at different temperatures and strain rates have been carried out. Then, the distributions of the effective plastic strain, the equivalent plastic strain rate and the hydrostatic stress were analyzed using finite elements method. Recommendations on process conditions were proclaimed at the end of this work according to the obtained numerical results.
1 citations
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18 Apr 2005TL;DR: In this paper, a unified multiaxial fatigue life model for isotropic and anisotropic materials is proposed, where the critical plane is theoretically determined by minimizing the damage introduced by the hydrostatic stress amplitude, which makes the proposed model have almost no applicability limitations with respect to different materials.
Abstract: A unified multiaxial fatigue life model for isotropic and anisotropic materials is proposed. The proposed fatigue model is a critical plane-based model. Most of the earlier models based on the critical plane approach assume that the critical plane only depends on the stress state. In the current model, the critical plane not only depends on the stress state but also on the material property. The critical plane is theoretically determined by minimizing the damage introduced by the hydrostatic stress amplitude, which makes the proposed model have almost no applicability limitations with respect to different materials. A wide range of fatigue data, which covers both brittle and ductile metals, isotropic and anisotropic materials are chosen to validate the proposed methodology. Generally, the predictions based on the proposed model agree with the experimental observations very well.
1 citations