Soil Plasticity

With the Geomechanics Module, you can define the properties for modeling materials exhibiting soil plasticity and elastoplastic soil. This material model can be used together with linear and nonlinear elastic materials. The following soil material models are available:

• Mohr–Coulomb
• Drucker–Prager
• Elliptic cap
• Tension cutoff
• Matsuoka–Nakai
• Lade–Duncan
• Nonlocal plasticity
  • Implicit gradient

Concrete and Rock

The Geomechanics Module lets you define the properties for modeling materials with failure criteria representative of concrete and rock, typically describing failure due to tensile stress. These material models can be used together with the Linear Elastic Material and Nonlinear Elastic Material features. The following concrete and rock material models are available:

Concrete

• Ottosen
• Bresler–Pister
• Willam–Warnke
• Coupled damage–plasticity
• Mazars damage
• Tension cutoff

Rock

• Original Hoek–Brown
• Generalized Hoek–Brown
• Tension cutoff

Damage

The deformation of quasibrittle materials, such as concrete or ceramics, under mechanical loads is characterized by an initial elastic deformation. If a critical level of stress or strain is exceeded, a nonlinear fracture phase will follow the elastic phase. As this critical value is reached, cracks grow and spread until the material fractures. The occurrence and growth of the cracks play an important role in the failure of brittle materials, and there are a number of theories to describe such behavior. The following damage models are available:

• Equivalent strain criterion
  • Rankine
  • Smooth Rankine
  • Norm of elastic strain tensor
  • User defined
• Phase field damage
• Regularization
  • Crack band
  • Implicit gradient
  • Viscous regularization
• Mazars damage for concrete

Elastoplastic Soil

The Elastoplastic Soil Material feature is used to model stress–strain relationships that are nonlinear even at infinitesimal strains. The following soil material models are available:

• Modified Cam–Clay
• Modified structured Cam–Clay
• Extended Barcelona basic
• Hardening soil
• Hardening soil small strain
• Nonlocal plasticity
  • Implicit gradient

Elastoplastic Ductile Materials

In addition to elastoplastic material models for soil, the Geomechanics Module gives you access to the following two elastoplastic models for ductile materials, such as metals:

• von Mises
• Tresca
• User-defined plasticity
• Nonlocal plasticity
  • Implicit gradient

Additional elastoplastic material models are available in the Nonlinear Structural Materials Module.

Nonlinear Elasticity

As opposed to hyperelastic materials, where the stress–strain relationship becomes significantly nonlinear at moderate to large strains, nonlinear elastic materials present nonlinear stress–strain relationships even at infinitesimal strains. The following nonlinear elasticity models are available:

• Ramberg–Osgood
• Hyperbolic law
• Hardin–Drnevich
• Duncan–Chang
• Duncan–Selig
• Small-strain overlay
• User defined

Additional material models are available with the Nonlinear Structural Materials Module.

Creep

Creep is an inelastic time-dependent deformation that occurs when a material is subjected to stress (typically much less than the yield stress) at sufficiently high temperatures. In the Geomechanics Module, user-defined creep is available, as well as the possibility to enter user-defined inelastic strain rate expressions.

Additional material models are available with the Nonlinear Structural Materials Module.