Material Models

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Numerous material models are available in NairnMPM.

Define a Material

You create materials using a Material command block. Within that block all material properties are set using property commands. Refer to each material type to learn about its possible properties.

Linear Elastic Small Strain Materials

The materials in this section are all small-strain, linear elastic materials. They account for rotations by using a hypoelastic correction based on the Jaumann Derivative.

Name ID Description Pσ Pε AS 3D
Isotropic 1 Linear elastic, isotropic X X X X
Transverse 1 2 Linear elastic, transversely isotropic with unique axis in the z direction X X X X
Transverse 2 3 Linear elastic, transversely isotropic with unique axis in the y direction X X X X
Orthotropic 4 Linear elastic, orthotopic material X X X X
Bistable 10 Elastic, isotropic material with two stable states having different properties X X X

The table columns on the right indicate if each material can be used in plane stress (Pσ), plane strain (Pε), axisymmetric (AS), or 3D calculations.

Hyperelastic Materials

The materials in this section are designed to solve problems in finite strains; they are formulated within the framework of hyper elasticity formulation.

Name ID Description Pσ Pε AS 3M 3D
Mooney-Rivlin 8 Elastic, isotropic and Ideal Rubber Elasticity X X X X
IdealGas 22 Ideal gas as hyperelastic material X X X
HEAnisotropic 21 Anisotropic, hyperelastic material X

The table columns on the right indicate if each material can be used in plane stress (Pσ), plane strain (Pε), axisymmetric (AS), with a 3D membrane (3M), or 3D calculations.

Elastic-Plastic Small Strain Materials

The materials in this section are all small-strain, elastic-plastic materials. They account for rotations by using a hypoelastic correction based on the Jaumann Derivative. They handle plasticity by combining one of these materials with any compatible hardening law.

Name ID Description Pσ Pε AS 3D
IsoPlasticity 9 Small-strain, isotropic, elastic-plastic material X X X X
MGEOSMaterial 17 Small-strain, isotropic, elastic-plastic material using a Mie-Grüneisen equation of state. X X X X
HillPlastic 15 Anisotropic, elastic-plastic material. X X X

The table columns on the right indicate if each material can be used in plane stress (Pσ), plane strain (Pε), axisymmetric (AS), or 3D calculations.

Hyperelastic-Plastic Materials

The materials in this section are formulated within the framework of hyper elasticity formulation. They can handle plasticity by combining them with any compatible Hardening Laws.

Name ID Description Pσ Pε AS 3D
HEIsotropic 24 Isotropic, hyperelastic-plastic material X X X
HEMGEOSMaterial 25 Isotropic, hyperelastic-plastic material using a Mie-Grüneisen equation of state. X X X

The table columns on the right indicate if each material can be used in plane stress (Pσ), plane strain (Pε), axisymmetric (AS), or 3D calculations.

Viscoelastic Materials

The materials in this section are viscoelastic materials materials.

Name ID Description Pσ Pε AS 3D
Viscoelastic 6 Small-strain, linear viscoelastic material with sum of relaxation times X X X X


The table columns on the right indicate if each material can be used in plane stress (Pσ), plane strain (Pε), axisymmetric (AS), or 3D calculations.

Rigid Materials

Rigid materials can be used either to apply moving velocity, temperature, or concentration boundary conditions or to interact with non-rigid material by contact mechanics.

Name ID Description Pσ Pε AS 3D
Rigid 6 A rigid material that interacts by boundary conditions or by contact X X X X

The table columns on the right indicate if each material can be used in plane stress (Pσ), plane strain (Pε), axisymmetric (AS), or 3D calculations.

Material Class Hierarchy

Materials are C++ classes. The following class hierarchy shows the orginzation of those C++ classes in the NairnMPM source code. A material in green is an abstract class that is never assigned to particles. All others are material classes (by their name and their ID in parentheses):

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