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MotionSolve Reference Guide
This manual provides a detailed list and usage information regarding command statements, model statements, functions and the Subroutine Interface available in MotionSolve.
NLFE Statements
NLFE Statements - Material Properties
MAT2
Material Property ElementMAT2 lets you define a hyper-elastic material model for NLFE elements that follows the incompressible Neo-Hookean material law.

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MotionSolve Reference Guide
This manual provides a detailed list and usage information regarding command statements, model statements, functions and the Subroutine Interface available in MotionSolve.
- Notation and Syntax
- Creating MotionSolve XML Files
- Writing Custom Elements for MotionSolve
- Writing Custom Functions for MotionSolve
- Supported Versions - Third Party Software
- Command Statements
- Model Statements
- Functions
- The Subroutine Interface for MotionSolve
- ADM/ACF Entities
- NLFE Statements
  - NLFE Statements - Line Elements
  - NLFE Statements - Connector Elements
  - NLFE Statements - Concentrated Mass Elements
  - NLFE Statements - Material Properties
    - MAT1
      Material Property ElementMAT1 lets you define a linearly elastic, isotropic material model for NLFE elements that follows Hooke's law.
    - MAT1LS
      Material Property ElementMAT1LS lets you define a linearly elastic, isotropic material model for NLFE elements that follows Hooke's law. This material employs a linear strain model.
    - MAT2
      Material Property ElementMAT2 lets you define a hyper-elastic material model for NLFE elements that follows the incompressible Neo-Hookean material law.
    - MAT3
      Material Property ElementMAT3 lets you define a hyper-elastic material model for NLFE elements that follows the compressible Neo-Hookean material law.
    - MAT4
      Material Property ElementMAT4 lets you define a hyper-elastic material model for NLFE elements based on the Mooney-Rivlin material model.
    - MAT5
      Material Property ElementMAT5 lets you define a hyper-elastic material model for NLFE elements based on the Yeoh material model.
    - MAT6 (deprecated)
      Material Property ElementThis material model is deprecated. Please see for more information.
  - NLFE Statements - Geometric Properties
  - NLFE Statements - Model Element
- msolve API Statements

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MAT2

Material Property ElementMAT2 lets you define a hyper-elastic material model for NLFE elements that follows the incompressible Neo-Hookean material law.

Format

<MAT2
       id       = "integer"
       mu       = "real"       
       nu       = "real"
       rho      = "real"
       YS       = "real"
/>

Attributes

id: Unique material property identification number.
mu: Shear modulus for the element.
nu: Poisson's ratio for the element. Default is 0.49.
rho: Element density.
YS: An elastic limit for strain. Default is 0.0.; YS >= 0.0

Example

The example demonstrates the definition of a MAT2 element.

<MAT2 id="1" mu="1.906036" nu="0.499" rho="2.150e-6" YS="0.125"/>

Comments

This material element defines a hyper-elastic material that obeys the incompressible Neo-Hookean law for the strain energy density function:
$U = \frac{μ}{2} ({\bar{I}}_{1} - 3) + \frac{k}{2} {(J - 1)}^{2}$
where
$μ$ is the shear modulus; $μ = N K T$ , where N is the number of polymer chains per unit volume, K is the Boltzmann constant, and T is temperature
$k = \frac{2 μ (1 + v)}{3 (1 - 2 v)}$ is the bulk modulus
$v$ is the Poisson's ratio
${\bar{I}}_{1} = J^{\frac{- 2}{3}} I_{1}$ , $I_{1} = t r (C) = r_{x}^{T} r_{x} + r_{y}^{T} r_{y} + r_{z}^{T} r_{z}$
$J = \det (J) = r_{x}^{T} (r_{y} \times r_{z})$
Each element must have a unique material identification number.
This material model can only be used with a fully parameterized element (BEAM12, QUAD12, TRIA12 and solid elements).
YS lets you specify a maximum limit on the elastic strain that the component is allowed. If, during the simulation, the component strain (at any element in the component) exceeds this value, MotionSolve issues a warning message.