Modeling of anisotropic damage and creep deformation in brittle rocks

2006 ◽  
Vol 43 (4) ◽  
pp. 582-592 ◽  
Author(s):  
J.F. Shao ◽  
K.T. Chau ◽  
X.T. Feng
Keyword(s):  
Creep Deformation ◽  
Anisotropic Damage ◽  
Brittle Rocks

Coupling Analysis between Stress Induced Anisotropic Damage and Permeability Variation in Brittle Rocks

2007 ◽  
Vol 340-341 ◽  
pp. 1133-1138 ◽  
Author(s):  
Hui Zhou ◽  
Jian Fu Shao ◽  
Xia Ting Feng ◽  
Da Wei Hu
Keyword(s):  
Damage Model ◽  
Coupling Model ◽  
Mechanical Analysis ◽  
Effective Porosity ◽  
Anisotropic Damage ◽  
Permeability Evolution ◽  
Coupling Analysis ◽  
Brittle Rocks ◽  
Permeability Variation ◽  
Set Up

In this paper, a coupling constitutive model is proposed for anisotropic damage and permeability variation in brittle rocks before cracks fully coalesce. In this coupling model, an anisotropic damage model is employed to perform the mechanical analysis, and a statistical penetration model is set up to describe the effective porosity and permeability evolution in brittle rocks. For the coupling analysis, anisotropic damage model offers statistical penetration model the crack length in various directions, and statistical penetration model inversely provides anisotropic damage model with permeability of rock for coupling hydro-mechanical analysis. The proposed coupling model is applied to Lac du Bonnet granite, and generally a good agreement is obtained between numerical simulations and experimental data.

scholarly journals A Micromechanical Anisotropic Damage Model for Brittle Rocks With Non-Associated Plastic Flow Rule Under True Triaxial Compressive Stresses

2021 ◽  
Vol 9 ◽  
Author(s):  
Shuangshuang Yuan ◽  
Qizhi Zhu ◽  
Wanlu Zhang ◽  
Jin Zhang ◽  
Lunyang Zhao
Keyword(s):  
Plastic Flow ◽  
Damage Model ◽  
Local Stress ◽  
Inclusion Problem ◽  
Flow Rule ◽  
Model Parameters ◽  
Anisotropic Damage ◽  
True Triaxial ◽  
Brittle Rocks ◽  
Plastic Flow Rule

A micromechanical anisotropic damage model with a non-associated plastic flow rule is developed for describing the true triaxial behaviors of brittle rocks. We combine the Eshelby’s solution to the inclusion problem with the framework of irreversible thermodynamics. The main dissipative mechanisms of inelastic deformation due to the frictional sliding and damage by microcrack propagation are strongly coupled to each other. A Coulomb-type friction criterion is formulated in terms of the local stress applied onto the microcracks as the yielding function. The back-stress term contained in this local stress plays a critical role in describing the material’s hardening/softening behaviors. With a non-associated flow rule, a potential function is involved. Some analytical analysis of the non-associated micromechanical anisotropic damage model are conducted, which are useful for the model parameters calibration. The proposed model is used to simulate the laboratory tests on Westerly granite under true triaxial stresses. Comparing the numerical simulation results provided by the models with associated/non-associated plastic flow rule and experimental results, it is clear that the proposed non-associated model gives a better prediction than the previous associated model.

Anisotropic Damage for Aluminium

2002 ◽  
Vol 5 (2-3-4) ◽  
pp. 269-285 ◽  
Author(s):  
Patrick Croix ◽  
Franck Lauro ◽  
Jérôme Oudin
Keyword(s):  
Anisotropic Damage

scholarly journals The Strain Rate Sensitivity and Creep Behavior for the Tripler Plane of Potassium Dihydrogen Phosphate Crystal by Nanoindentation

Micromachines ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 369
Author(s):  
Jianhui Mao ◽  
Wenjun Liu ◽  
Dongfang Li ◽  
Chenkai Zhang ◽  
Yi Ma
Keyword(s):  
Strain Rate ◽  
Strain Rate Sensitivity ◽  
Creep Deformation ◽  
Potassium Dihydrogen Phosphate ◽  
Rate Sensitivity ◽  
Dislocation Nucleation ◽  
Machining Process ◽  
Dihydrogen Phosphate ◽  
Potassium Dihydrogen ◽  
Kdp Crystals

As an excellent multifunctional single crystal, potassium dihydrogen phosphate (KDP) is a well-known, difficult-to-process material for its soft-brittle and deliquescent nature. The surface mechanical properties are critical to the machining process; however, the characteristics of deformation behavior for KDP crystals have not been well studied. In this work, the strain rate effect on hardness was investigated on the mechanically polished tripler plane of a KDP crystal relying on nanoindentation technology. By increasing the strain rate from 0.001 to 0.1 s−1, hardness increased from 1.67 to 2.07 GPa. Hence, the strain rate sensitivity was determined as 0.053, and the activation volume of dislocation nucleation was 169 Å3. Based on the constant load-holding method, creep deformation was studied at various holding depths at room temperature. Under the spherical tip, creep deformation could be greatly enhanced with increasing holding depth, which was mainly due to the enlarged holding strain. Under the self-similar Berkovich indenter, creep strain could be reduced at a deeper location. Such an indentation size effect on creep deformation was firstly reported for KDP crystals. The strain rate sensitivity of the steady-state creep flow was estimated, and the creep mechanism was qualitatively discussed.

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