Contact with standard coulomb friction

[kiakarim]

Hello everyone,

we encounter some problems with the contact module in 8.6.1j and attached a demo input file.
To specify the problem: We want to use friction stan coulomb however we do not see any changes both in reactions as well as deformations for varying friction coefficients.
Is there any missing statement in our Inputfile // do we miss a certain point?

Thank you!!

Best Regards

[Prof. R.L. Taylor]

There is a bug such that the old position is somehow not tracked.  It needs careful debugging to trace the problem.  So far I have only detected that the code does traverse the correct routines.

[Prof. R.L. Taylor]

There are errors in you file.

1. Missing penalty for tangential forces (add 1d5)

2. Friction needs unsymmetric solver (utang)

3. Made friction 0.3 to test and reduced dt.

It still may have bugs (for example, using Lagrange multiplier for normal not working).  Seems to need quite a few iterations, so may still be linearization checks.

[Prof. R.L. Taylor]

Here is file I used to test

[Prof. R.L. Taylor]

Attached

[kiakarim]

Hi Prof. Taylor,

thank you, this brings us a few steps further!!