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Subsubsection 4.1.3.17: Coupled Mooney-Rivlin Up Subsection 4.1.3: Unconstrained Materials Subsubsection 4.1.3.19: Ogden Unconstrained

#### 4.1.3.18 Coupled Veronda-Westmann

The material type for the coupled Veronda-Westmann material is coupled Veronda-Westmann. The following material parameters can be defined.
 Veronda-Westmann c1 parameter [P] Veronda-Westmann c2 parameter [P] k “Bulk-modulus” [P]
The coupled Veronda-Westmann material is an unconstrained formulation of the Veronda-Westmann material and is defined by the following strain-energy function. Here, and are the first and second invariants of the right Cauchy-Green deformation tensor C and is the determinant of the deformation gradient tensor.
This material model uses a standard displacement-based element formulation, so care must be taken when modeling materials with nearly-incompressible material behavior to avoid element locking. For (nearly-) incompressible materials, use the Veronda-Westmann material described in Section 4.1.2.15↑.
Example:
<material id="1" type="coupled Veronda-Westmann">
<c1>10.0</c1>
<c2>1.0</c2>
<k>100.0</k>
</material>


Subsubsection 4.1.3.17: Coupled Mooney-Rivlin Up Subsection 4.1.3: Unconstrained Materials Subsubsection 4.1.3.19: Ogden Unconstrained