How to create a Fluid incompressible material

[OscarPacheco]

Hello!

I need to create a material that has to work as an incompressible fluid. I cannot find in the interface the right command to create it.
Any help?

Thank you!

 

[IceBreakerSours]

Incompressibility is treated as a constraint on the degrees of freedom of the nodes of an element. You just need to change the element type to 'hybrid' and that is sufficient. So, for instance, C3D8 can be C3D8H.

Note every new 'knob' in FEA comes with its own cost and challenges so read the manual carefully.

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[Mustaine3]

The element type alone does not make the material incompressible. The appropriate material data are also necessary.

Maybe Fluid Cavity is an alternative. See manuals for details.

 

[IceBreakerSours]

Yes, I missed pointing that out.

From a practical standpoint, many materials (or states of deformation such as plastic flow) must be treated as incompressible to make the analytical/computational problems tractable. For instance, constrained rubber under pressure may show high forces in an experiment with very little deformation. Without an additional degree of freedom (i.e., pressure DOF), trying to capture such a phenomenon numerically will be a futile exercise.

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[OscarPacheco]

Thank you both! Your info has been very useful!