Reaction forces in stress solve

[mark smith]

Hi Elmer community
Is there an easy way to obtain the reaction forces & moments at restraints ?
thanks in advance.
Regards
mark

[raback]

You might apply the same methodolgy as with the computation of drag. Didn't test though but it should work if the default linear system wrapper is used witin the solver...

You may compute the residual of the discrete system r=Ax-b where A does not include the effect of BCs. For stress solver the residual includes the nodal force vectors needed to reproduce the displacement field. To activate the computation add to the Solver section the following keyword.

Code: Select all

  Calculate Loads = Logical True

As a result you should obtain 'Displacement Loads' vector with DIM components.

You still need to sum up these contributions. That you can do with the SaveScalars solver (see Models Manual). You should operate on the desired component and sum up the values on a given boundary. The following might give you the forces in x and y direction.

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Solver 2
  Procedure = "SaveData" "SaveScalars"  
  Filename = reactionforce.dat
  Operator 1 = boundary sum
  Variable 1 = Displacement Loads 1
  Variable 2 = Displacement Loads 2 
End

When you also add to the desired boundary the flag.

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  Save Scalars = Logical True

The overall procedure is far from elegant but most of the functionality was not designed for this purpose. This could be made more transparent for the user with some effort...

There is some internal force integration behind the model lumping algorithms in StressSolve. Maybe they could also be of some use if you're interested in net forces.

BR, Peter

[mark smith]

Hi Peter
Thanks;-)
Best regards
mark