A generalized Hill’s lemma and micromechanically based macroscopic constitutive model for heterogeneous granular materials

2010 ◽  
Vol 199 (49-52) ◽  
pp. 3137-3152 ◽  
Author(s):  
Xikui Li ◽  
Xue Zhang ◽  
Junbo Zhang
2011 ◽  
Vol 71-78 ◽  
pp. 1073-1078
Author(s):  
Xiao Xia Guo ◽  
Bo Ya Zhao

In order to construct a constitutive model taking into the effect of both the fabric tensors and their evolution modes, this paper links modern ideas of thermomechanics opinion to the theory of fabric tensors. The anisotropic dissipation incremental function of modified Cam-clay constitutive model considering the effect of fabric characteristic can be obtained by establishing the relation between microstructure and plastic volume strain. After discussing the yield surfaces in the dissipative and the true stress space from the viewpoint of the evolution mode of the fabric tensors, the results indicate that the slope of the normal consolidation line and the critical state line will be governed by changes of void fabric. The model successfully captures most salient behaviors of granular materials related to fabric issues. In the dissipative stress space, the void of granular materials can rearrange and show more anisotropic. In the true stress space, fabric not only affects the deflection of the yield surface, but also affects the hardening rule.


2011 ◽  
Vol 682 ◽  
pp. 590-616 ◽  
Author(s):  
JIN SUN ◽  
SANKARAN SUNDARESAN

A constitutive model is developed for the complex rheology of rate-independent granular materials. The closures for the pressure and the macroscopic friction coefficient are linked to microstructure through evolution equations for coordination number and fabric. The material constants in the model are functions of particle-level properties and are calibrated using data generated through simulations of steady and unsteady simple shear using the discrete element method (DEM). This model is verified against DEM simulations at complex loading conditions.


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