Hello FeBio Support,
We are researchers at the University of Minnesota looking at modeling skeletal muscle using FeBio. We have created multiple models and have searched through the Message boards, but we have been unable to find the appropriate solution to our problem: Our skeletal muscle is not behaving correctly when we apply a "prescribed isotropic active contraction". Instead of maintaining volume our muscle is shrinking and shortening, instead of expanding at the constant rate of shortening. We believe this is occurring due to our fiber definitions, but are having difficulty defining our fibers based on the manual examples. Secondly, the literature mostly defines skeletal models using hex elements, but we are unable to create a volume mesh from our imported STLs using hex elements in FeBio. What software would you recommend for accomplishing this task as it has proven more difficult than first thought?
Our muscle material definition is provided below.
We look forward to your response.
Cheers,
John
<material id="2" name="Muscle" type="solid mixture">
<mat_axis type="local">1,4,5</mat_axis>
<solid type="trans iso Mooney-Rivlin">
<density>1</density>
<c1>30000</c1>
<c2>10000</c2>
<k>60000</k>
<c3>0</c3>
<c4>0</c4>
<c5>0</c5>
<lam_max>1.8</lam_max>
</solid>
<solid type="fiber-exp-pow-uncoupled">
<alpha>0.3579</alpha>
<beta>2</beta>
<ksi>5.3992</ksi>
<theta>20</theta>
<phi>90</phi>
<k>5399.2</k>
</solid>
<solid type="fiber-exp-pow-uncoupled">
<alpha>0.3579</alpha>
<beta>2</beta>
<ksi>5.3992</ksi>
<theta>-20</theta>
<phi>90</phi>
<k>5399.2</k>
</solid>
<solid type="prescribed isotropic active contraction">
<T0 lc="7">26000</T0>
</solid>
</material>
We are researchers at the University of Minnesota looking at modeling skeletal muscle using FeBio. We have created multiple models and have searched through the Message boards, but we have been unable to find the appropriate solution to our problem: Our skeletal muscle is not behaving correctly when we apply a "prescribed isotropic active contraction". Instead of maintaining volume our muscle is shrinking and shortening, instead of expanding at the constant rate of shortening. We believe this is occurring due to our fiber definitions, but are having difficulty defining our fibers based on the manual examples. Secondly, the literature mostly defines skeletal models using hex elements, but we are unable to create a volume mesh from our imported STLs using hex elements in FeBio. What software would you recommend for accomplishing this task as it has proven more difficult than first thought?
Our muscle material definition is provided below.
We look forward to your response.
Cheers,
John
<material id="2" name="Muscle" type="solid mixture">
<mat_axis type="local">1,4,5</mat_axis>
<solid type="trans iso Mooney-Rivlin">
<density>1</density>
<c1>30000</c1>
<c2>10000</c2>
<k>60000</k>
<c3>0</c3>
<c4>0</c4>
<c5>0</c5>
<lam_max>1.8</lam_max>
</solid>
<solid type="fiber-exp-pow-uncoupled">
<alpha>0.3579</alpha>
<beta>2</beta>
<ksi>5.3992</ksi>
<theta>20</theta>
<phi>90</phi>
<k>5399.2</k>
</solid>
<solid type="fiber-exp-pow-uncoupled">
<alpha>0.3579</alpha>
<beta>2</beta>
<ksi>5.3992</ksi>
<theta>-20</theta>
<phi>90</phi>
<k>5399.2</k>
</solid>
<solid type="prescribed isotropic active contraction">
<T0 lc="7">26000</T0>
</solid>
</material>
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