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IDProjectCategoryView StatusDate SubmittedLast Update
0000763OpenFOAMBugpublic2013-03-04 17:322013-03-05 16:00
Reporteruser610Assigned Tohenry  
PriorityhighSeverityfeatureReproducibilityalways
Status resolvedResolutionfixed 
Summary0000763: structure expanding when external pressure is increased (solidDisplacement)
DescriptionDear Foamers, after inspecting solvers like solidDisplacementFoam (and similar) i found, that increase of pressure on surface leads to expansion of material!

This error have roots in patch description: surface normal pressure is added to traction (but it must be subtracted), let's see to tractionDisplacementFvPatchVectorField.C

Code:

    gradient() =
    (
        (traction_ + pressure_*n)/rho
      + twoMuLambda*fvPatchField<vector>::snGrad() - (n & sigmaD)
    )/twoMuLambda;

But it must be:

Code:

    gradient() =
    (
        (traction_ - pressure_*n)/rho
      + twoMuLambda*fvPatchField<vector>::snGrad() - (n & sigmaD)
    )/twoMuLambda;

I think, that this error must be eliminated in next versions
Steps To Reproduceplace "-" sign:



    gradient() =
    (
        (traction_ - pressure_*n)/rho
      + twoMuLambda*fvPatchField<vector>::snGrad() - (n & sigmaD)
    )/twoMuLambda;
TagsNo tags attached.

Activities

henry

2013-03-05 16:00

manager   ~0001955

I agree that it is more logical to define the applied pressure to +ve, thanks for the report.

Resolved by commit 6502e850de67d1fc0b461b820372202afe9fe819

Issue History

Date Modified Username Field Change
2013-03-04 17:32 user610 New Issue
2013-03-05 16:00 henry Note Added: 0001955
2013-03-05 16:00 henry Status new => resolved
2013-03-05 16:00 henry Resolution open => fixed
2013-03-05 16:00 henry Assigned To => henry