numgeo features are vast number of multi-phase element formulations that can be used for quasi-static as well as dynamic problems. The following gives an overview over the available formulations and possible applications:
Elements which discretise the displacement of the solid phase and the pore fluid pressure. They are available for a two or three phase medium, discretising one or two pore pressures, respectively. A typical application would be the dynamic excitation of an unsaturated soil
Elements which discretise the displacement of the solid phase, the pore fluid pressure and the displacement of the pore fluid. They give the user more freedom over the boundary condition as the displacement of the pore fluid can be set independently
Elements which discretise the displacement of the solid phase and the displacement of the pore fluid. Depending on the studied problem, they can be superior to the u-p and u-p-U element formulations since they show a better convergence behaviour
numgeo offers a wide variety of sophisticated constitutive soil models. That includes the following models:
Hypoplastic model with intergranular strain
This constitutive model can be used to realistically capture the behaviour of granular soil under both monotonic and cyclic loading. Originally proposed by von Wolffersdorff in 1996 for monotonic loading only, it was extended to cyclic loading by Niemunis and Herle in 1997.
High-cycle accumulation model by Niemunis et al.
The High-cycle accumulation (HCA) model by Niemunis, Wichtmann and Triantafyllidis is a model for high-cyclic loading of granular media. It has been proven by numerous simulations of boundary value problems to be a suitable model for the study of long-term deformations due to high-cyclic loading.
Since many geotechnical problems involve contacts, sophisticated contact discretisation methods are implemented in numgeo:
Surface-to-Surface mortar discretisation
The Surface-to-Surface mortar discretisation allows for the geometrically exact integration of contact stresses. This makes it superior to all other contact discretisation techniques. Up until now, the mortar contact discretisation is only implemented for 2D applications
The implemented Surface-to-Surface method allows for large-deformation analysis of contact pairs with arbitrary meshing. However, exact results may sometimes require a finer mesh compared to the mortar method as the integration of contact pressure is not as exact. The Surface-to-Surface discretisation is available for both 2D and 3D Simulations
Constitutive contact models
Apart form simple Mohr-Coulomb frictional contact models, numgeo also incorporates more sophisticated models based on the continuum constitutive models described in the section Constitutive Models