Elmer Discussion Forum

I'd try to give

Linear System Nullify Guess = True

there is nothing non-linear in the solution If ElasticSolver is used, the strain measure will be a nonlinear function of displacements. If nothing special is given in the sif file, the nonlinear measure of strain is computed as E = 1/2 [grad u + grad u^T + (grad u)^T(grad u)]. StressSolve neglects ...

Thanks for suggesting this - What might not yet be ideal is that the test UseUMAT = ListCheckPresentAnyMaterial(CurrentModel, 'UMAT Subroutine') leads to altering the way of computing loads in a coupled analysis even when the solver doesn't use UMAT in any way. Probably it would be better to apply a...

IsotoCedex wrote: ↑17 May 2024, 10:34 The result is identical,

It seems that Elmer really generates a source term from the given Pressure Source definition. I believe it may make only a very small modification of the model. You might notice a change if the source is scaled to make it larger.

If you have a mesh consisting of second-order nodal elements (and avoid giving a conflicting element command "Element = p:..."), the solver should create a discretization based on second-order approximation of all fields. Such solution may however be unstable so it may suffer from spurious...

This is an old solver which was designed to use the lowest-order basis functions together with additional bubble basis functions to get a stable method. Therefore the second-order basis is not supported by this implementation. The given element definition of the form Element = "p:1 b:n" ma...

After checking the solver code I think a given Pre Strain is used only in special cases where the effect of geometric stiffness is activated (Stability Analysis = True or Geometric Stiffness = True). If you update to get the change https://github.com/ElmerCSC/elmerfem/commit/48ade7a16ddaeee4ceefe731...

Do you know whether this change in the routines will happen soon? If you update to obtain the change https://github.com/ElmerCSC/elmerfem/commit/7a166454a4559e7518da7f1ae79ab01f1aa44250 it might now be possible to apply Conforming BC in connection with a 1-D model. I also added a simple test https:...

Do I need to put additional input there? I would expect not as CBC should just replace the dofs with the corresponding node and checked a test . I think there is a problem in the library subroutines that prevents the creation of constraints when the boundary is defined in terms of point (101) eleme...

Here the keywords "Quadratic Approximation" and "Use Piola Transform" relate to the 3-D solvers where the discretization is done in terms of curl-conforming (edge element) basis functions. The 2-D version uses standard basis functions and doesn't need these commands. However it m...