Contact parameter with adhesion

[BuuNguyen]

Dear STKO,
I have 2 questions for contact parameter (zerolengthContactASDimplex)

1/ why it does not have the cohesion c parameter in Coulomb friction model?
2/ do you think it should have shear stress limit t_max as an additional parameter to limit the shear strength in friction model? (as in the attached figure).

thank you for your time,
Buu

[STKO Team]

1/ why it does not have the cohesion c parameter in the Coulomb friction model?

The cohesion is to simulate cohesive zones, i.e. thin layers of materials that offer a shear strength (cohesion) even if the contact pressure is 0.

In our case, we implemented a contact surface, i.e. something that simulates the behavior between two bodies that are detached from each other, and there will be a shear strength only due to friction, i.e. only when you have contact pressure.

2/ do you think it should have shear stress limit t_max as an additional parameter to limit the shear strength in friction model? (as in the attached figure).

t_max is automatically computed by the friction model, is not a user parameter.
tau_max = -mu * sigma_n, if sigma_n < 0 (i.e. if in contact)

[BuuNguyen]

2/
t_max is automatically computed by the friction model, is not a user parameter.
tau_max = -mu * sigma_n, if sigma_n < 0 (i.e. if in contact)

I mean the limit value of tau_max, as you can see in the figure, tau_max is linearly proportional to sigma_n till reaches a limit value of tau_max, and not further increases anymore.

Thank you for your time,
Buu

[STKO Team]

Oh ok I see, I thought it was a tau/slip graph, instead it is a tau/pressure graph.
Of course it's possible, we will implement it in the near future