Thermodynamics based models for granular and porous materials have been widely used in the development of more complex models. Broadly speaking, there exists two approaches; in both, the first law of thermodynamics enables one to model the recoverable response. However, the approaches differ slightly when dealing with the second law of thermodynamics, i.e. irreversable processes. The French school approach introduces the notion of thermodynamic forces, flow and evolution rules. Ziegler's

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... h directly postulates a positive dissipation function on a dissipative stress space, which then requires an extra mapping step to the true stress space. Despite the fact that they both have the same foundations, differences emerge between them regarding the way in which stored energy is accounted for in the development of kinematic and/or isotropic hardening. In Ziegler's approach, the stored energy is solely used for the kinematic hardening, as opposed to the French school approach in which the stored energy is allowed in both cases of hardening. Despite which modelling approach is taken, we will show how certain modifications to these theories have to be made in order to develop classical models.