Hypoplastic material models for soil-structure interaction problems

Soils behave in a complicated manner and follow different loading and unloading paths. Such models can be seen under the elastoplastic framework. However, that would explicit definition of yield function and differentiation between elastic and plastic regime. However, the behavior of soils are more complicated. Hypoplastic material models provide an alternative approach and have been shown to be a good choice for modeling cohesionless soils. They describe the realistic behavior of soils, which is both nonlinear and in-elastic. These models are described through rate equations and dissipation may occur even if the deformation is elastic in nature. Thus, they cannot be expressed using an elastic strain energy function. There are several rates that are being used in literature & here we employ the Jaumann rate to define an implicit function of the stress. In this work the von Wolfferdorff hypoplastic model is numerically implemented using AceGen. The convergence behavior of the hypoplastic model is also investigated.