Utilizing 'Hard' or other non-linear contact formulation from Calculix!

Sarvesh

@Victor, @Sergio, @Disla,
Is there anyway or workaround wherein we can enforce 'Hard' contact within Mecway without struggling with contact stiffness trial an error method? Also, there are other non-linear contact formulation feasible within Calculix environment, how to use these non-linear formulations effectively within Mecway?
Many thanks in advance.
Best Regards
Sarvesh

Sergio

Hi, you could define the surface or node groups in Mecway, and then define the contact as a CCX custom model definition, and writing by hand the appropiated cards.

disla

Hard pressure-overclosure behavior is internally reduced to linear pressure-overclosure behavior. That's probably why Victor didn't implement Hard. With linear you cover hard.

Hard uses default values that sometimes fail, specially if your contat need some friction to work.

It can unnecesarly increase the computation time.

If you want to try anyway to convince yourself you need something like this.

Sergio

In fact, I didn´t find any improvements using the other contact options or kind of contacts in my mechanical simulations, is just a matter of adjusting the contact stiffness and sometimes switching the master/slave pairs.

Sarvesh

Hello Sergio and Disla,
Thank you for the precise help and guidance. It worked like a charm. Many thanks for useful tips and guidance.

Best Regards
Sarvesh

Sergio

Guess that the path is starting with the default contact stiffness, and if you see that the contact is not detected at all, switch the contact pairs. If you see that there is some penetration in the contact area, then increase the contact stiffness (maybe by one order of magnitud if your mesh is not too big). Increasing the contact stiffnes will decrease the penetration, but also take more time to compute, so is a balance, you must decide how much is tolerable.