Search found 155 matches

by mika
23 Mar 2020, 18:00
Forum: ElmerSolver
Topic: Structure Analysis with both Beam and Shell elments
Replies: 16
Views: 1436

Re: Structure Analysis with both Beam and Shell elments

An ideal implementation of the coupled shell and beam analysis would be to assemble both models to a single system which would then be solved simultaneously. Nevertheless this type of approach has not yet been implemented. Since the models have compatible DOFs, it might be possible to implement this...
by mika
23 Mar 2020, 12:04
Forum: ElmerSolver
Topic: Introducing springs to a point/face as a boundary condition
Replies: 62
Views: 3096

Re: Introducing springs to a point/face as a boundary condition

After checking the code quickly, I think the linear elasticity solver might assemble node-wise springs already if the target nodes were listed in the mesh.boundary file to define zero-dimensional parts of the boundary. Instead of using the keyword Target Nodes, the keyword Target Boundaries should t...
by mika
21 Mar 2020, 15:05
Forum: ElmerSolver
Topic: Introducing springs to a point/face as a boundary condition
Replies: 62
Views: 3096

Re: Introducing springs to a point/face as a boundary condition

Hi,

Unfortunately node-wise spring constraints (the case 4) are ignored by the large-displacement solver. I could try to make a fix so that node-wise springs would be assembled.

A spring constraint given directly over an edge or a face should nevertheless work.

-- Mika
by mika
26 Feb 2020, 17:49
Forum: ElmerPost
Topic: A small question about viewing results of magnetic field
Replies: 4
Views: 2448

Re: A small question about viewing results of magnetic field

"magnetic flux density" gives the best global fit where the basis for the approximation is spanned by the usual Lagrange (nodal) basis functions. "magnetic flux density e" is obtained by making the best fit elementwise without solving a large system. The first way (the global fit) may smear disconti...
by mika
25 Feb 2020, 13:05
Forum: Software development
Topic: Edge degrees of freedom
Replies: 4
Views: 1597

Re: Edge degrees of freedom

I add that the way to get the right number of DOFs is not unique nevertheless. I think the definitions

Variable DOFs = 4
Element = "n:0 e:1"

should in principle serve as well, with a chance of getting more useful aliases.

-- Mika
by mika
25 Feb 2020, 11:08
Forum: Software development
Topic: Edge degrees of freedom
Replies: 4
Views: 1597

Re: Edge degrees of freedom

I'd also set "Variable DOFs = 2" so that the two components would represent the real and imaginary parts. This is the way how Elmer has traditionally handled the approximation of complex-valued fields and following this convention offers a better way to utilize general library routines. The element ...
by mika
24 Feb 2020, 15:30
Forum: Software development
Topic: Edge degrees of freedom
Replies: 4
Views: 1597

Re: Edge degrees of freedom

Hi, Elmer should offer pretty much general support for associating degrees of freedom with different geometric entities of a background mesh, so this should be possible to do. Nevertheless the case of approximating two curl-conforming fields simultaneously hasn't been exemplified yet, although I hav...
by mika
21 Feb 2020, 16:34
Forum: ElmerSolver
Topic: Tutorial 2D Turbulent flow Model k-e is diverge
Replies: 3
Views: 382

Re: Tutorial 2D Turbulent flow Model k-e is diverge

An iterative solution of the same linear system may fail in parallel although the same solver parameters (the same sif file) lead to the solution in a serial run. Typically this may happen when an algebraic preconditioner (for example ILUn) is applied, since Elmer computes a different preconditioner...
by mika
06 Feb 2020, 10:12
Forum: ElmerSolver
Topic: multiple fluxsolver
Replies: 1
Views: 255

Re: multiple fluxsolver

Any chance that there is a missing "End" statement in the sif file (before "Material 2" section starts)?

-- Mika
by mika
03 Feb 2020, 18:31
Forum: ElmerSolver
Topic: Calculate 3D stress tensor for static equilibrium
Replies: 6
Views: 477

Re: Calculate 3D stress tensor for static equilibrium

Solid mechanics models of Elmer are displacement-based and the generation of stress inside the body necessarily means straining of the material. On the other hand, a rigid deformation means that the material strain vanishes and hence no stress is expected in this case. I think setting Young's modulu...