Contact controls parameter 2

[scandroglio]

Hello,
thanks a lot to all forum for help about force visualization in Abaqus.
Now I have another question about contact controls in Abaqus.
During analysis involving contact surface, when the convergence is difficult I use the following parameters:

*CONTACT CONTROLS, STABILIZE
*CONTACT CONTROLS, AUTOMATIC TOLERANCES
*CONTROLS, ANALYSIS = DISCONTINUOUS

The contact controls STABILIZE added a dumping to stabilize the solution.
I see that this parameter is very "strong" but I'm not sure if "thrust the solution" and give incorrect result.
Is good use this parameter?(this parameter help a lot in instance of not convergence solution)
Is there someone that Can give me other valid contact parameter to convergence the solution in instance of difficult convergence?

Thank and kind regards

 

[deveng100]

Hi,
Yeah it is helpful; indeed ..and most important it decreases that damping to zero by the last increment in the step..so pratically it halps to initiate and give you fairly accurate result bythe end..Only thing don't play with default parameteers too much.
Other options may by global stabilize and tied contact with adjust
REgards
Devashish

 

[rlhanlon]

Try specifiying the damping factor within *static
that is, *static,stabilize,factor=1e-06

Try a multi step analysis, and for each step reduce the damping factor. Therefore you may want to try:

*static,stabilize,factor=1e-06
*static,stabilize,factor=1e-05
*static,stabilize,factor=1e-04


down to
*static,stabilize,factor=1e-01

Remember, that when stabilisation is used with *static, a viscous damping force Fv is introduced, so that ABAQUS solves the equations,

P-I-Fv = 0 (P = Applied Load, I = Internal Load, Fv = Viscous damping)

The inaccuracy is because the additioinal term Fv is introduced into the equation.

WITHOUT stabilisation, ABAQUS will solve P-I=0.

Using stabilisation will make your solution less accurate but if you try running a contact problrm without it, then the chances are that your solution will NOT converge.