An algorithm and a modular subroutine for the CAP model

Abstract

SUMMARYA cap model algorithm and the associated FORTRAN subroutine, CAP, are presented. The algorithm lends itself to a wide range of soil and rock cap models, and can easily be incorporated into most dynamic codes. The routine permits the user to obtain flexibility with respect to changes in functional forms and parameters with minor coding changes.

Uniaxial and triaxial compression tests of silicon carbide ceramics under quasi-static loading condition.

“…concrete) having non-negligible porosity, variation of shear stresses at failure with respect to mean stresses can be described using a cap model (Sandler andRubin, 1979 andFossum et al, 1995). For ceramics like SiC, having porosity less than 0.2%, the cap feature in such models is unnecessary, but the limit function (Fossum and Brannon, 2004) that describes the peak attainable stresses in terms of all three stress invariants seems appropriate.…”

“…In this case, the first stress invariant, I 1 , and the square root of the deviator invariant, J 2 , at failure (σ 1 =σ f ) are P I f 2 3 2 1 1 Table 1. During the shear failure of the specimens, the state of stress can be represented as a shear failure criterion represented empirically by the following limit function (Fossum and Brannon, 2004;modified after Sandler andRubin, 1979 andFossum et al, 1995). Figure 16 shows an expansion of the quasi-static failure criterion by including the plate-impact test data (Vogler et al, 2004) on the SiC-N specimens.…”

Laboratory evaluation of damage criteria and permeability of Big Hill salt.

“…Table 3 summarizes the results from our laboratory experimental program of Big Hill salt consisting of eight triaxial compression tests and a uniaxial compression test. The cap plasticity model (Sandler and Rubin, 1979) is formulated in terms of two stress invariants. In the triaxial compression tests, the axial stress was the major principal stress, σ 1 , and the confining pressure, P, was acting as the intermediate, σ 2, and the minimum, σ 3 , principal stresses, respectively.…”

“…Then, the stress invariants at the onset of dilation can be described as, Table 3. During the dilatant damage of the specimens, the state of stress can be represented by the following exponential equation (Sandler andRubin, 1979 andFossum et al, 1995). The same damage data from the triaxial compression tests may also be described in terms of the principal stresses.…”

Constitutive models for the Etchegoin Sands, Belridge Diatomite, and overburden formations at the Lost Hills oil field, California

“…The ESR cap model is a generalization of the soil and rock constitutive model of Sandier and Rubin (1979). The model is designed to represent the elastic-plastic behavior of porous rock and soil.…”