*friction,lagrange or *friction,rou 1

[han_cyuan]

*friction,lagrange or *friction,rough may cause convergence difficulty when used in conjunction with the *surface behavior, augmented lagrange or penalty option. Use penalty friction instead.
How to deal with it

 

[FEA way]

The message is pretty self-explanatory. You should use the penalty friction formulation if you encounter convergence issues with rough or lagrange friction in conjunction with the penalty or augmented lagrange method for enforcement of contact constraints in the normal direction. If you don’t have convergence issues, you can ignore this message.

 

[han_cyuan]

I would like to ask if you need to set penalty friction in the following two steps.

 

[FEA way]

There you should only set Friction formulation to Penalty. Unless you want to keep it as Frictionless, of course.

 

[han_cyuan]

How many recommended parameters should be set?

 

[FEA way]

Just the friction coefficient.

 

[han_cyuan]

Is there any numerical range limit?

 

[FEA way]

It can be any non-negative value but it should make sense physically - check the friction coefficient for a given pair of materials in contact.

 

[han_cyuan]

So I can't assume a friction coefficient on my own?

 

[FEA way]

If you want realistic results, it has to make sense. But it’s easy to find approximate values for most common materials.