On Thu, Oct 13, 2016 at 11:57 AM, Rossi, Simone <sro...@email.unc.edu> wrote:
> Dear all, > I’m playing around with the elasticity tests in the system of equations > examples (more specifically Ex4 and Ex5). > In particular I’m trying to set the poisson ratio to nu = 0.49995. > With this choice the solution I get using second order lagrangian elements > does not make any sense. > For first order elements the solution looks more reasonable, but still > different from what I get from FreeFEM++. > Does it depend on the enforcement of the Dirichlet boundary conditions? > Thanks, > Simone > nu=0.49995 is almost incompressible. Normally people use special formulations for that type of problem, e.g. a mixed method to enforce almost incompressibility (similar to Stokes in fluids). That probably explains why you get bad results by naively using the simple formulation from ex4 and ex5. David ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, SlashDot.org! http://sdm.link/slashdot _______________________________________________ Libmesh-users mailing list Libmesh-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/libmesh-users
