TetrahedronHyperelasticityFEMForceField

This component belongs to the category of ForceField. The TetrahedronHyperelasticityFEMForceField implements – for tetrahedral topology only – several non-linear mechanical constitutive laws, also named as hyperelastic constitutive laws. The available models are:

• Arruda-Boyce model
• Costa model
• Mooney-Rivlin model
• Neo-Hookean model
• Ogden model (order 1)
• St Venant-Kirchhoff model
• Veronda-Westmann model

Data

• materialName: name of the material to be used, the possible options are:
  • “ArrudaBoyce”
  • “Costa”
  • “MooneyRivlin”
  • “NeoHookean”
  • “Ogden”
  • “StVenantKirchhoff”
  • “VerondaWestman”
• ParameterSet: global parameters specifying the material, the number of data depends on the materialName given:
  • for “ArrudaBoyce”, two parameters are required:
  • for “Costa”, eight parameters are required:
  • for “MooneyRivlin”, three parameters are required:
  • for “NeoHookean”, two parameters are required:
  • for “Ogden”, three parameters are required:
  • for “StVenantKirchhoff”, two parameters are required:
  • for “VerondaWestman”, parameters are required:
• AnisotropyDirections: global directions of anisotropy of the material, it is a vector<Coord> i.e. a vector containing at each entry a vector which size is the dimension of your degrees of freedom (e.g. 3 if Vec3d). The size of the array is 0 if the material is isotropic, 1 if it is transversely isotropic and 2 for orthotropic materials.
• topology: link towards the TetrahedronSetTopologyContainer associated to your degrees of freedom in the node or in the graph

Usage

As a Forcefield, the TetrahedronHyperelasticityFEMForceField requires a MechanicalObject and the associated solvers (integration scheme and linear solver), as well as a TetrahedronSetTopologyContainer.

Example

This component is used as follows in XML format:

<TetrahedronHyperelasticityFEMForceField name="HyperElasticMaterial" materialName="StVenantKirchhoff" ParameterSet="3448.2 31034.4"/>

with a St Venant-Kirchhoff model using the parameters: Using SofaPython3:

node.addObject('TetrahedronHyperelasticityFEMForceField', name="HyperElasticMaterial", materialName="StVenantKirchhoff", ParameterSet="3448.2 31034.4")

An example scene involving a TetrahedronHyperelasticityFEMForceField is available in examples/Components/forcefield/TetrahedronHyperelasticityFEMForceField.scn