Static Structural Analysis - Calculating Reaction force of Applied force

Numerical methods and mathematical models of Elmer
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FEMUser
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Static Structural Analysis - Calculating Reaction force of Applied force

Post by FEMUser »

Hello all.

Need community help. I produced a very generic static structural model with two boundary conditions. One is a surface fixation (Displacement zero in X, y and Z) and the other a Load of of nN in the z direction normal to surface (Imagine a cube). I want to calculate the reaction at my fixation point but don't know how. I am using the Latest Elmer in Windows. It looks like I have to add some changes to the .Sip file. Anyone can guide me through the process? I can't seem to understand how to do this.

Regards,
FEMuser
kevinarden
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Re: Static Structural Analysis - Calculating Reaction force of Applied force

Post by kevinarden »

https://www.nic.funet.fi/pub/sci/physic ... Manual.pdf

You can look at Chapters 58-60 in the models manual for outputting data. There is a boundary output where you can output the sum at the boundary. The problem is that I don't know what the reaction variable at the boundary is called. One of my problems with using Elmer effectively is there is no list of variables for each solver.
raback
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Re: Static Structural Analysis - Calculating Reaction force of Applied force

Post by raback »

Hi

"Calculate Loads = Logical True" will compute the reaction forces and they will probably be called "Displacement Load" and have components 1, 2 and 3 each representing nodal load in the different directions.

-Peter
kevinarden
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Re: Static Structural Analysis - Calculating Reaction force of Applied force

Post by kevinarden »

SaveScalars: -----------------------------------------
SaveScalars: Saving scalar values of various kinds
WARNING:: SaveScalars: Requested variable does not exist: displacement load 1
WARNING:: SaveScalars: Found no values to save
mcase.sif
(1.9 KiB) Downloaded 89 times
kevinarden
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Re: Static Structural Analysis - Calculating Reaction force of Applied force

Post by kevinarden »

They do come out in paraview as Displacement Loads, and can be summed of the boundary in paraview.
kevinarden
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Re: Static Structural Analysis - Calculating Reaction force of Applied force

Post by kevinarden »

Worked it out, Displacement Loads is plural. The attached sif works.

Solver 2
Exec Solver = After Timestep
Equation = SaveScalars
Procedure = "SaveData" "SaveScalars"
Filename = "forces.dat"
Variable 1 = Displacement Loads 1
Operator 1 = boundary sum
End

and you have to add save scalars to the boundary condition
Boundary Condition 1
Target Boundaries(1) = 4
Name = "fixed"
Displacement 1 = 0
Displacement 3 = 0
Displacement 2 = 0
Save Scalars = Logical True
End
mcase.sif
(1.93 KiB) Downloaded 81 times
raback
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Re: Static Structural Analysis - Calculating Reaction force of Applied force

Post by raback »

Thanx Kevin! It is sometimes hard to remember all the keywords by heart. .-Peter
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