Hello dealii mates, A short description of the problem here: I am solving the eigenvalues for a linear elastic solid body, where free boundaries are applied (zero Neumann). This project follows the tutorial step-36 and step-17 using Lame parameters for isotropic materials.
Unfortunately, or I deserve it as a newbie, got a petsc error about zero pivot, which I presume is due to the six rigid body modes. The website below mentions creating nullspace, but I have no idea how to do it. Additionally, I want to see how many rigid modes I have to ensure my boundary conditions are applied correctly. The reason is that I previously encountered three rigid modes, which is so wrong for free vibration, due to improperly indexed Jacobian (not dealii). Can anyone help on this or generally offer some suggestions? I would greatly appreciate that in advance. [0]PETSC ERROR: Zero pivot in LU factorization: https://petsc.org/release/faq/#zeropivot [0]PETSC ERROR: Zero pivot row 1 value 4.23516e-22 tolerance 2.22045e-14 Please forgive me for being greedy here, this wee project will be the basement of my next electromechanical problem, which highly depends on static condensation with an inhomogeneous rhs vector. If anyone has found something similar or might be helpful in tutorials, please let me know, thanks! Cheers, Yuchen Liu -- The deal.II project is located at http://www.dealii.org/ For mailing list/forum options, see https://groups.google.com/d/forum/dealii?hl=en --- You received this message because you are subscribed to the Google Groups "deal.II User Group" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion visit https://groups.google.com/d/msgid/dealii/7e4a87cc-bee6-4a99-8194-01d8e171a5b4n%40googlegroups.com.
