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The material type for an ellipsoidal continuous fiber distribution is “ellipsoidal fiber distribution”. Since fibers can only sustain tension, this material is not stable on its own. It must be combined with a stable compressible material that acts as a ground matrix, using a “solid mixture” container as described in Section 4.1.3.22↓. The following material parameters need to be defined:

<material id="1" type="solid mixture">
  <mat_axis type="local">0,0,0</mat_axis>
  <solid type="neo-Hookean">
    <E>1000.0</E>
    <v>0.45</v>
  </solid>
  <solid type="ellipsoidal fiber distribution">
    <ksi>10, 12, 15</ksi>
    <beta>2.5, 3, 3</beta>
  </solid>
</material>