Hello,
I am modeling the indentation of a cell (modeled here as a parallepipedic neo-hookean elastic solid) by a spherical rigid indenter. I wish to compress the cell all the way to the bottom.
In the user documentation, it recommends in this case taking the augmented Lagrangian method, with a penalty factor worth E*A/V (E is Young's modulus, A is an element area and V is an element volume), the single pass method, and to have a coarser mesh for the rigid indentor than for the soft cell.
However, I am surprised to see that my model converges best when using the penalty factor method, with a higher penalty factor than recommended (between 10-100 times higher), the double pass method, and to have a finer mesh for the rigid indentor (this part is actually what surprises me most). Does someone have an explanation for this? Is this because I am setting some parameters incorrectly?
(nb: by better convergence, I mean that the computations converge for higher indentations, and that the reaction force on the rigid body rigid.Fz is very close to the reaction force computed using the Cauchy tensor and surface normals inside the cell)
Also, as I refine all meshes while keeping mesh size ratios intact, I often do not obtain a better convergence. How can we explain that, and is there some changes I should make to observe this expected behavior? Would it help to do quarter symmetry?
Many thanks for your help,
Lionel
I am modeling the indentation of a cell (modeled here as a parallepipedic neo-hookean elastic solid) by a spherical rigid indenter. I wish to compress the cell all the way to the bottom.
In the user documentation, it recommends in this case taking the augmented Lagrangian method, with a penalty factor worth E*A/V (E is Young's modulus, A is an element area and V is an element volume), the single pass method, and to have a coarser mesh for the rigid indentor than for the soft cell.
However, I am surprised to see that my model converges best when using the penalty factor method, with a higher penalty factor than recommended (between 10-100 times higher), the double pass method, and to have a finer mesh for the rigid indentor (this part is actually what surprises me most). Does someone have an explanation for this? Is this because I am setting some parameters incorrectly?
(nb: by better convergence, I mean that the computations converge for higher indentations, and that the reaction force on the rigid body rigid.Fz is very close to the reaction force computed using the Cauchy tensor and surface normals inside the cell)
Also, as I refine all meshes while keeping mesh size ratios intact, I often do not obtain a better convergence. How can we explain that, and is there some changes I should make to observe this expected behavior? Would it help to do quarter symmetry?
Many thanks for your help,
Lionel
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