Boundary conditions - face and edge naming collision

Numerical methods and mathematical models of Elmer
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jscan
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Joined: 15 Mar 2016, 08:01
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Boundary conditions - face and edge naming collision

Post by jscan »

Hi there.
I'm running a very simple eigenvalue simulation, getting the modes of vibration for a 3d solid box restricted on one face.
I'm running into the issue that when I add a boundary condition to say, boundary number 5, it is applied to both surface 5 and line 5. What am I doing wrong here?
I've attached my code, as well as a paraview screenshot where the displacement of surface 6 or the right and line 6 on the left are both kept at 0.
The box is meshed using gmsh, and then converted using ElmerGrid. I'm running the Windows ElmerSolver Version: 8.2 (Rev: Release, Compiled: 2016-03-15)
Thanks for your help.
Jerome.

case.sif:

Code: Select all

Header
  CHECK KEYWORDS Warn
  Mesh DB "." "plinth"
  Include Path ""
  Results Directory ""
End

Simulation
  Max Output Level = 5
  Coordinate System = Cartesian
  Coordinate Mapping(3) = 1 2 3
  Simulation Type = Steady state
  Steady State Max Iterations = 1
  Output Intervals = 1
  Timestepping Method = BDF
  BDF Order = 1
  Solver Input File = case.sif
  Post File = case.ep
End

Constants
  Gravity(4) = 0 -1 0 9.82
  Stefan Boltzmann = 5.67e-08
  Permittivity of Vacuum = 8.8542e-12
  Boltzmann Constant = 1.3807e-23
  Unit Charge = 1.602e-19
End

Body 1
  Target Bodies(1) = 1
  Name = "plinth"
  Equation = 1
  Material = 1
End

Solver 1
  Equation = Linear elasticity
  Eigen System Values = 35
  Procedure = "StressSolve" "StressSolver"
  Variable = -dofs 3 Displacement
  Eigen System Select = Smallest magnitude
  Eigen Analysis = True
  Exec Solver = Always
  Stabilize = True
  Bubbles = False
  Lumped Mass Matrix = False
  Optimize Bandwidth = True
  Steady State Convergence Tolerance = 1.0e-5
  Nonlinear System Convergence Tolerance = 1.0e-7
  Nonlinear System Max Iterations = 20
  Nonlinear System Newton After Iterations = 3
  Nonlinear System Newton After Tolerance = 1.0e-3
  Nonlinear System Relaxation Factor = 1
  Linear System Solver = Direct
  Linear System Direct Method = Umfpack
End

Solver 2
  Exec Solver = after timestep 
  Equation = "result output"
  Procedure = "ResultOutputSolve" "ResultOutputSolver"
  Output File Name = "case"
  Output Format = String "vtu"
  Binary Output = True
  Single Precision = True
End

Equation 1
  Name = "Equation 1"
  Active Solvers(2) = 1 2
End

Material 1
  Name = "Concrete"
  Mesh Poisson ratio = 0.2
  Density = 2300.0
  Poisson ratio = 0.2
  Youngs modulus = 40.0e9
End

Boundary Condition 1
  Target Boundaries(1) = 6
  Name = "fixed"
  Displacement 3 = 0
  Displacement 2 = 0
  Displacement 1 = 0
End
Attachments
plinth.JPG
plinth.JPG (44.55 KiB) Viewed 1678 times
plinthonly.zip
(1.87 MiB) Downloaded 202 times
raback
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Re: Boundary conditions - face and edge naming collision

Post by raback »

Hi

2D boundary and 1d boundary are treated the same way. If you want to skip 1d boundary perhaps you can give it another index. Or you can remove altogether the lower dimensional objects by (-removelowdim flag in ElmerGrid).

-Peter
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