×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Issue with CNVTOL command

Issue with CNVTOL command

Issue with CNVTOL command

(OP)
Hi all,

I am trying to figure out the CNVTOL command for defining convergence criteria and am having some strange results.

I have a solution that solves ok with default solution settings (SOLCONTROL,ON). The solution features nonlinear materials and contact so according to the help file the only convergence check is on the out-of-balance forces.

However, if I define convergence criteria explicitly using the default settings given in the help file (CNVTOL,F,,0.005,2,0.01) and run the solution again, the force convergence criterions shown in the output file are different to those I observe when using the default solution controls. For example

Using Default Solution Settings (SOLCONTROL,ON):

EQUIL ITER 3 COMPLETED. MAX DOF INC = 0.8968E-07
FORCE CONVERGENCE VALUE = 0.6312E-03 CRITERION = 0.6607E-04
EQUIL ITER 4 COMPLETED. MAX DOF INC = 0.5462E-07
FORCE CONVERGENCE VALUE = 0.1934E-03 CRITERION = 0.5792E-04
EQUIL ITER 5 COMPLETED. MAX DOF INC = 0.1928E-07
FORCE CONVERGENCE VALUE = 0.4422E-04 CRITERION = 0.5803E-04
>>> SOLUTION CONVERGED AFTER EQUILIBRIUM ITERATION 5

Using Default Solution Settings (SOLCONTROL,ON) and explicitly stating default convergence criteria (CNVTOL,F,,0.005,2,0.01):

EQUIL ITER  3 COMPLETED. MAX DOF INC = 0.8968E-07
FORCE CONVERGENCE VALUE = 0.6312E-03 CRITERION = 0.6094E-04
EQUIL ITER  4 COMPLETED. MAX DOF INC = 0.5462E-07
FORCE CONVERGENCE VALUE = 0.1934E-03 CRITERION = 0.5235E-04
EQUIL ITER  5 COMPLETED. MAX DOF INC = 0.1928E-07
FORCE CONVERGENCE VALUE = 0.4422E-04 CRITERION = 0.5141E-04
>>> SOLUTION CONVERGED AFTER EQUILIBRIUM ITERATION 5

Why is it that the criterions are different to those using the default settings? Is there some additional convergence criteria that is adjusted with SOLCONTROL,ON?

Also, is it possible at all to output the program-calculated solution controls that have been set using the SOLCONTROL,ON command for a specific analysis?

Many thanks,
Dave

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources