Calculate Stresses in StressSolver

Numerical methods and mathematical models of Elmer
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rserrano
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Joined: 12 Oct 2014, 20:32
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Calculate Stresses in StressSolver

Post by rserrano »

Hi all Elmer users,

I am working with StressSolver and I need to save the stresses. I have seen that this is possible in some kind of analysis, like in EigenAnalysis. I try to simulate one nodal harmonic force on a plate surface. I am running Harmonic Analysis, and in this case, Elmer saves all my stresses with zero value (files ep, vtk,dat,...), but it calculates the displacement field well. I do not know if I am writing something bad in my sif or if this is an Elmer problem. I atached my sif:

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

Simulation
Max Output Level = 4
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 = "Body 1"
Equation = 1
Material = 1
End

Solver 1
Equation = Linear elasticity
Procedure = "StressSolve" "StressSolver"
Variable = -dofs 3 Displacement
Harmonic Analysis = True
Frequency = 10000
Exec Solver = Always
Stabilize = True
Calculate Stresses = Logical True
Bubbles = False
Lumped Mass Matrix = False
Optimize Bandwidth = True
Steady State Convergence Tolerance = 1.0e-5
Nonlinear System Convergence Tolerance = 1.0e-8
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 = Iterative
Linear System Iterative Method = CG
Linear System Max Iterations = 100000
Linear System Convergence Tolerance = 1.0e-8
Linear System Preconditioning = ILU2
Linear System ILUT Tolerance = 1.0e-3
Linear System Abort Not Converged = False
Linear System Residual Output = 1
Linear System Precondition Recompute = 1
End

Equation 1
Name = "Equation 1"
Calculate Stresses = Logical True
Active Solvers(2) = 1 2
End

Material 1
Name = "Aluminium (generic)"
Heat expansion Coefficient = 23.1e-6
Heat Conductivity = 237.0
Sound speed = 5000.0
Heat Capacity = 897.0
Mesh Poisson ratio = 0.35
Density = 2700.0
Poisson ratio = 0.35
Youngs modulus = 70.0e9
End

Boundary Condition 1
Target Nodes(1) = 16
Name = "BoundaryCondition 1"
Displacement 3 Load = Real 1
End

Solver 2
Procedure = "SaveData" "SaveScalars"
Filename = "DATOS2C"
Variable 1 = Displacement
Variable 2 = Stress
Save Points (4) = 17 18 19 20
End

I have been reading the file StressSolve.src and compiling it with some changes, but I do not find where the problem is.

Thank you for your attention. Best regards,

Raúl
raback
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Re: Calculate Stresses in StressSolver

Post by raback »

Hi

Did you try also the .vtu format? There can indeed be problems as this is not a frequently used combination. A small test case could help.

-Peter
mancf
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Joined: 15 Jul 2015, 18:58
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Re: Calculate Stresses in StressSolver

Post by mancf »

Hi,
This problem seems to remain the same. Is there any possibility to solve it? I could provide a simple example where this problem appears.
Regards,
mancf
raback
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Posts: 4812
Joined: 22 Aug 2009, 11:57
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Re: Calculate Stresses in StressSolver

Post by raback »

Hi

You can confirm that this does not work with VTU output either. That is the only format where it should be supported.

-Peter
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