Material Models

Numerous material models are available in NairnMPM and OSUParticulas.

Define a Material

To use a material in calculations, you first must define it in the the input commands. This definition will create a material name (or ID or number) that can be used to assign that material to particles. When using NairnFEAMPM or NairnFEAMPMViz, a material is created with the command block:

Material ID,name,type
   Property value
   Property2 value
      .
      .
Done

where

• ID is the material ID (any string) that is used to reference this material in other commands.
• name is a name that will appear in output files to describe the material
• type is the type of material, which can be select by type name or number from the available material models.

Each material property is on a line with the property name and its value. Refer to each material type to see the properties needed. The property names are case sensitive (although NairnFEAMPM can usually handle any case).

A material definition in a XML input file has the form

<Material Type='1' Name='Polymer'>
   <Property>value</Property>
   <Property2>value</Property2>     
     .
     .
</Material>

where

* Type is the material type and must be entered by number corresponding to that material model.
* Name is any user-defined description of the the material.

Note that in XML files a materials does not have an ID, which is used in scripting files to refer to that material in other commands. Instead, other XML commands refer to define materials by number or name as follows:

Linear Elastic Small Strain Materials
Hyperelastic Materials
Elastic-Plastic Small Strain Materials
Hyperelastic-Plastic Materials
Viscoelastic Materials
Rigid Materials