β Scribed by Paul E. Senseny; Arlo F. Fossum; Tom W. Pfeifle
No coin nor oath required. For personal study only.
Two simple constitutive laws appropriate for elastic-plastic deformation up to peak load of low porosity rocks are presented. Both laws account for mean stress dependence of yield hardening between yield and peak strength and non-associative plastic straining. The two constitutive laws are based on the Mohr-Coulomb and the Mises-Schleicher yield criteria. The yield criteria are matched at axisymmetric compression and the relationships among the constitutive parameters are given. The parameters are then evaluated for two evaporite rocks anhydrite and polyhalite based on axisymmetric compression data. Comparison of predicted stress-strain laws with those measured in the laboratory show that these laws can be used for engineering analysis.
π SIMILAR VOLUMES
The use of micromechanically based constitutive equations for contact interfaces leads to technically relevant parameters to ill-conditioned finite-element equations. In the paper an augmented Lagrangian technique is employed to overcome this difficulty and to provide a good converging algorithm.