Search found 194 matches

by mika
27 Aug 2020, 17:25
Forum: ElmerSolver
Topic: structure frequency responses under vibration forces
Replies: 22
Views: 4440

Re: structure frequency responses under vibration forces

There exists an old and undocumented facet shell solver (FacetShellSolve) which utilizes drilling DOFs. While it's known that the facet shell elements may generally be unreliable (no convergence to solutions which a proper shell theory predicts, which gave a motivation to write a new shell solver), ...
by mika
26 Aug 2020, 14:17
Forum: ElmerSolver
Topic: structure frequency responses under vibration forces
Replies: 22
Views: 4440

Re: structure frequency responses under vibration forces

In the first place the development of the shell solver started by assuming a smooth shell so that the director data at the nodes would be unique. Now, when the shell consists of patches with a couple of patches meeting at right angles, I see possible troubles or at least sources of possible inaccura...
by mika
24 Aug 2020, 15:54
Forum: ElmerSolver
Topic: Include Multiple Frequencies in Harmonic Analysis
Replies: 3
Views: 1134

Re: Include Multiple Frequencies in Harmonic Analysis

Hi,

I would define the frequency to be a function of the (pseudo-)time. See for example the case CubeHarmonicShell in the tests directory of the code repository.

-- Mika
by mika
24 Aug 2020, 15:45
Forum: ElmerSolver
Topic: structure frequency responses under vibration forces
Replies: 22
Views: 4440

Re: structure frequency responses under vibration forces

i followed your instruction and using harmonic mode = true for analysis, the results can be calculated(with U 3 Load = Real and U3 Load Im = Real), but in the results at all frequencies, the imag part of u and dnu is all zero, is that correct? While it's logical to think that nodal loads could be s...
by mika
20 Aug 2020, 17:34
Forum: ElmerSolver
Topic: structure frequency responses under vibration forces
Replies: 22
Views: 4440

Re: structure frequency responses under vibration forces

It should be possible to make harmonic analysis with the shell solver, but you should now use a different command to activate the harmonic analysis. The solver section associated with the shell model should have the command "Harmonic Mode = True". Having two different keywords (Harmonic An...
by mika
20 Aug 2020, 13:28
Forum: ElmerSolver
Topic: adding plasma source term to continuity equation
Replies: 6
Views: 1319

Re: adding plasma source term to continuity equation

Hi, By a quick inspection it seems that creating a source term S for the continuity equation would require at least a small change of the code. If the nodal values of the source term would be inserted to the fourth row of the calling argument LoadVector of the subroutine NavierStokesCompose in FlowS...
by mika
18 Aug 2020, 15:46
Forum: ElmerSolver
Topic: Introducing springs to a point/face as a boundary condition
Replies: 63
Views: 13463

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

I just write to mention that the utility to add springs and masses is finally documented in the section "Adding pointwise springs and masses" of Elmer Models Manual http://www.nic.funet.fi/pub/sci/physics/elmer/doc/ElmerModelsManual.pdf Any new functionality hasn't been added recently, so ...
by mika
13 Aug 2020, 16:19
Forum: ElmerSolver
Topic: Eigenvalues in Axi Symmetric 2D
Replies: 7
Views: 3488

Re: Eigenvalues in Axi Symmetric 2D

I think the right conversion should be f = sqrt(eigenvalue)/(2 pi).

-- Mika
by mika
13 Aug 2020, 15:46
Forum: ElmerSolver
Topic: structure frequency responses under vibration forces
Replies: 22
Views: 4440

Re: structure frequency responses under vibration forces

The command "Harmonic Analysis = True" should provide a way to obtain the response in the case of a simple-harmonic forced vibration. This implies that the solution is sought as complex-valued. On the other hand I believe the modal superposition based on eigenmodes hasn't been implemented ...
by mika
13 Jul 2020, 09:58
Forum: General
Topic: Time discretization schemes
Replies: 3
Views: 2077

Re: Time discretization schemes

Is the documentation that you are referring to - Chapter 6/Elmer Solver Manual? Yes Would that code be TimeIntegrate.F90? Yes, this is the common place for time stepping subroutines. The subroutine names used there are quite descriptive: SUBROUTINE RungeKutta SUBROUTINE NewmarkBeta SUBROUTINE Adams...