Dear all,
I am asking your point of view about incompressible material simulation (e.g. rubber material) in ABAQUS.
When the material is incompressible a u/p formulation should be used instead of a displacement based formulation.
According to ABAUS manual one of the element suitable for a 3D incompressible analysis is a C3D8H (8 nodes brick for the displacements and constant pressure) or C3D20H (20 nodes brick for the diaplacements and 4 nodes for the pressure).
What I have read in literature (e.g. Finite element procedures by K.J. Bathe) the element C3D8H in ABAQUS is called Q1P0 and this element does not satisfy the inf-sup or LBB condition.
Does the C3D20H element satisfy the LBB condition?
Then another question: where are the 4 nodes for the pressure located in the C3D20H element?
Are they the vertex of a tetrahedra into the cube?
Thank you in advance to clarify me this doubt.
Regards,
Andrea