Coulomb-Mohr yield criterion

In accordance with the field sampling and rock mechanics test results, the rocks presented clear plastic deformation characteristics at different confining pressure conditions. In this paper, Mohr— Coulomb yield criterion was used to determine the... 

The idea of plastic yielding is also applied to granular materials, such as soils and powders. In this case, the shear stress required for deformation depends on the packing density, and the particle shape and surfaee characteristics. The shear resistance is commonly described by the Mohr-Coulomb yield criterion, i.e.. 

For a uniaxial compression test, determine the plane on which the maximum shear stress will occur for a material that obeys the Mohr-Coulomb yield criterion. Suggest an approach for measuring the material parameters (d>, Tq) in the Mohr-Coulomb yield criterion. (Hint construct the Mohr s circle (see Fig. 2.23) for various values of the normal stress.)... 

Overburden of the tunnel 100.0 m The rock mass is considered as the idealized elastoplastic material with the Mohr-Coulomb yield criterion, and all the materials of support system are treated as elastic material. The initial stress field of analysis zone is calculated as self-weight... 

Fig.5 The modified Mohr-Coulomb yield criterion with tension cutt-off ...

The Mohr-Coulomb failure criterion can be recognized as an upper bound for the stress combination on any plane in the material. Consider points A, B, and C in Fig. 8.4. Point A represents a state of stresses on a plane along which failure will not occur. On the other hand, failure will occur along a plane if the state of stresses on that plane plots a point on the failure envelope, like point B. The state of stresses represented by point C cannot exist since it lies above the failure envelope. Since the Mohr-Coulomb failure envelope characterizes the state of stresses under which the material starts to slide, it is usually referred to as the yield locus, YL. 

Eq. (8.24), and the modified Mohr-Coulomb yield (or failure) criterion, Eq. (8.27). It should be noted that other yield criteria, such as the von Mises criterion, are used to model the flow of bulk solids in hoppers, and more conditions may need to be imposed, such as the Levy flow rule, in order to close the system of equations [Cleaver and Nedderman, 1993],... 

Most amorphous solids and many crystalline ones, particularly non-metals and polymers, exhibit a Coulomb-Mohr-type (Coulomb 1773 Mohr 1900) yield criterion or plastic-shear resistance such that this resistance on the best shear plane is dependent on the normal stress acting across the plane of shear, resulting in a dependence of the type... 

Figure 11.12 Mohr circle diagram for two states of stress that produce yield in a material satisfying the Tresca yield criterion (a) and the Coulomb yield criterion (h)...

There are two other ways in which these results can be presented. First, recalling Section 11.2.6 and Figure 11.12, the Mohr circle diagram can be constructed from the data, as shown in Figure 11.19 where Bowden and Jukes s results appear as crossed points. This diagram leads naturally to a Coulomb yield criterion. 

For these calculations, three different material models were investigated a linear elastic, an elasto-brittle, and elasto-plastic ubiquitous joint model. The ubiquitous joint, elasto-plastic model, is defined by a two-dimensional yield criterion, composed of two Mohr-Coulomb criteria, along two predefined directions characterised by their normal vectors ni and n2. 

The Mohr-Coulomb criterion is used to represent the shear failure of coal. In the modelling studies, after yielding has occurred, the total strain is assumed to consist of three components the elastic, plastic and damage components. 

This model is based on the mean features of the Mohr-Coulomb model and is expressed with stress invariants [Maleki (1999)] instead of principal stresses. Until plasticity is reached, a linear elastic behaviour is assumed. It is fully described by the drained elastic bulk and shear moduli. The yield surface of the perfectly plastic model is given by equation 7. Function 7i(0) is chosen so that the shape of the criterion in the principal stress space is close to the Lade criterion. 

FLAG has several built-in material behavior models. The failure of rock material is assumed to follow the Mohr-Coulomb criterion as illustrated in Fig. 4 which is used for materials that yield when... 

The model calculation adopts the criterion of Mohr-Coulomb, and this yield criterion can be expressed as ... 

The Mohr-Coulomb criterion is regarded as coal yield condition. 

The failure criterion of soils was the Mohr-Coulomb equivalent area circle yield criterion that was advanced in reference (Xu G.Ch. and Zheng Y.R., 1990). This criterion was suitable for computing in the 3D space problems, and the material constants a and k were shown in formula (16) and formula (17). 

Yield in Mohr-Coulomb materials follows a criterion which is the sum of stress terms and the Mises criterion ... 

The yield stress of a material is a measured stress level that separates the elastic and inelastic behavior of the material. The magnitude of the yield stress is generally obtained from the results of a uniaxial test. However, the stresses in a structure are usually multiaxial. A measurement of yielding for the multiaxial state of stress is called the yield criterion. For example, the Mohr-Coulomb criterion, the Buyukozturk criterion, and the Drucker-Prager criterion are common yield criteria for concrete, and the von Mises criterion is the widely used yield criterion for steel. 

The well-known failure hypotheses of Tresca, Coulomb-Mohr and the yield locus concept of Jenike [1] and Schwedes [2] as well as the Warren-Spring-Equations [3 to 7] were specified from Molerus [8, 9] by the cohesive steady-state flow criterion. The consolidation and non-rapid, frictional flow of fine and cohesive particulate solids was explained by acting adhesion forces in particle contacts [8]. 

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