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4.13.1.3 Uncoupled Prescribed Isotropic Active Contraction
The material type for prescribed isotropic active contraction, in an uncoupled solid mixture, is “prescribed isotropic active contraction uncoupled”. This material must be combined with a stable uncoupled material that acts as a passive matrix, using a “uncoupled solid mixture” container as described in Section 4.1.2.14↑. The following material parameters need to be defined:
| <T0> | representing the prescribed stress | [P] |
The active stress for this material is given by Note: If the solid material in the mixture is (nearly) incompressible, this isotropic contraction will cause no change in the deformation.
Example:
Isotropic contraction in a mixture containing a Mooney-Rivlin solid.
<material id="1" type="uncoupled solid mixture">
<mat_axis type="local">0,0,0</mat_axis>
<solid type="Mooney-Rivlin">
<c1>1.0</c1>
<c2>0</c2>
<k>5.0</k>
</solid>
<solid type="prescribed isotropic active contraction uncoupled">
<T0 lc="2">1</T0>
</solid>
</material>