UMAT and mortar BC, 3

FredrikR · Post by **FredrikR** » 06 May 2024, 23:32

Hello!
To follow up from on an old post. UMAT with Mortar BC didn't seem to give proper displacement contact load values at the mortar boundaries.
I think it has to do with ElasticSolver is normally (without UMAT) solving Ku = F using the total displacement while with UMAT it is solving for the incremental displacement.

I tried with the following modification in CalculateLoads in SolverUtils.F90

Code: Select all

13655       CALL MatrixVectorMultiply( Aaid, x, TempVector )
...
13713     ELSE
13714       UseUMAT = ListCheckPresentAnyMaterial(CurrentModel, 'UMAT Subroutine')
13715       IF (UseUmat) THEN
13716         CALL Info( 'CalculateLoads', 'Umat, omitting K*x', Level=5)
13717         TempVector = -RHS
13718       ELSE
13719         CALL Info( 'CalculateLoads', 'Not Umat, using K*x', Level=5)
13720         TempVector = TempVector - RHS
13721       END IF
13722       !TempVector = TempVector - RHS
13723     END IF

(line 13714-13721 are added)

It seems to give reasonable values.

/Fredrik