Showing 3 results for Constitutive Model
R. Naghdabadi and A. Saeedi,
Volume 23, Issue 1 (7-2004)
Abstract
In this paper, an elastic constitutive model based on the Eulerian corotational rate of the logarithmic strain tensor is proposed. Using this model, the large deformation of a closed cycle containing tension, shear, compression and inverse shear is analyzed. Since the deformation path includes a closed cycle and the material is considered as an isotropic elastic material, the normal and shear components of the stress at the end of the cycle must vanish. Using conventional constitutive models, the non-zero solution for the stress components is obtained. Using the proposed constitutive model, the normal and shear components of stress at the end of the cycle are obtained to be exactly equal to zero.
M. Maleki,
Volume 27, Issue 1 (7-2008)
Abstract
In this paper, an elastoplastic constitutive model is presented for predicting sandy soil behavior under monotonic and cyclic loadings. The model is based on the CJS3 model that takes into account deviatoric and isotropic mechanisms of plasticity. The flow rule in deviatoric mechanism is non-associated and a kinematic hardening law controls the evolution of the
yield surface. In the present study, the critical state surface and history surface separating the virgin and cyclic states in the stress space are defined. Hardening modulus and stress-dilatancy law for monotonic and cyclic loadings are effectively modified. Taking the hardening modulus as a function of deviatoric and volumetric plastic strain, the model will be capable of predicting sand behavior once the history surface and stress reversal are defined. All model parameters have clear physical meanings and can be determined simply from laboratory tests. The results of homogeneous tests on Hostun sand are used to validate the model. The results of validation indicate the capability of the proposed model.
M. Salari, A. Akhtarpour,
Volume 36, Issue 2 (3-2018)
Abstract
The most important features and phenomena of the deformation behavior of rockfills are stress-dependent stiffness, hardening and dilative (or contractive) behaviors, as well as breakage, rotation and redistribution of particle size. An elasto-plastic constitutive model has been suggested by Vermeer and de Borst to simulate the shear behavior of soils, concretes and rocks. This research has tried to improve this model for numerical simulation of the shear behavior of rock fills. The improvement of the model has been performed through proposing new mobilized dilation and friction angles functions and new relationships for some parameters. For validation, a series of large-scale triaxial tests performed on the rockfill shell of Masjed-e-Soleyman dam have been simulated with the improved model. The results show that the improved Vermeer-De Borst model has a good accuracy to simulate the shear behavior of rockfills numerically.
