Reply To: Static Structural Analysis Model Doesn’t Converge

[lis29]

I turned NR residual to 4 and the simulation still crashed, but got much further than it did before. I'm attaching the solutions branch contact tool here, as well as the last few lines of the solver output file. What's the best way to evaluate what's causing the convergence issue? 

 

    EQUIL ITER  22 COMPLETED.  NEW TRIANG MATRIX.  MAX DOF INC=  0.1951E-01
     DISP CONVERGENCE VALUE   =  0.1951E-01  CRITERION=  0.7500E-02
     LINE SEARCH PARAMETER =   1.000     SCALED MAX DOF INC =  0.1951E-01
     FORCE CONVERGENCE VALUE  =   1.808      CRITERION=   4.455     <<< CONVERGED
    Writing NEWTON-RAPHSON residual forces to file: file.nr001
    EQUIL ITER  23 COMPLETED.  NEW TRIANG MATRIX.  MAX DOF INC=  0.2220E-01
     DISP CONVERGENCE VALUE   =  0.2220E-01  CRITERION=  0.8610E-02
     LINE SEARCH PARAMETER =   1.000     SCALED MAX DOF INC =  0.2220E-01
     FORCE CONVERGENCE VALUE  =   1.954      CRITERION=   4.546     <<< CONVERGED
    Writing NEWTON-RAPHSON residual forces to file: file.nr002
    EQUIL ITER  24 COMPLETED.  NEW TRIANG MATRIX.  MAX DOF INC=  0.2525E-01
     DISP CONVERGENCE VALUE   =  0.2525E-01  CRITERION=  0.9872E-02
     LINE SEARCH PARAMETER =   1.000     SCALED MAX DOF INC =  0.2525E-01
     FORCE CONVERGENCE VALUE  =   7.778      CRITERION=   4.638   
    Writing NEWTON-RAPHSON residual forces to file: file.nr003
    EQUIL ITER  25 COMPLETED.  NEW TRIANG MATRIX.  MAX DOF INC=  0.2590E-01
     DISP CONVERGENCE VALUE   =  0.2590E-01  CRITERION=  0.1113E-01
     LINE SEARCH PARAMETER =   1.000     SCALED MAX DOF INC =  0.2590E-01
     FORCE CONVERGENCE VALUE  =   6.809      CRITERION=   4.647   
    Writing NEWTON-RAPHSON residual forces to file: file.nr004
    EQUIL ITER  26 COMPLETED.  NEW TRIANG MATRIX.  MAX DOF INC=  0.2953E-01

 *** ERROR ***                           CP =   15009.078   TIME= 08:13:14
 Solution not converged at time 4.14475 (load step 5 substep 5).        
  Run terminated.   

 

 

After this, there were a number of summary for contact pairs, and then this:

         R E S T A R T   I N F O R M A T I O N

 REASON FOR TERMINATION. . . . . . . . . .UNCONVERGED SOLUTION                   
 FILES NEEDED FOR RESTARTING . . . . . . .  file0.Rnnn
                                            file.ldhi
                                            file.rdb
 TIME OF LAST SOLUTION . . . . . . . . . .  4.1437   
    TIME AT START OF THE LOAD STEP . . . .  4.0000   
    TIME AT END OF THE LOAD STEP . . . . .  5.0000   
 NOTE: FOR CONVERGING SOLUTIONS, ADDITIONAL EQUILIBRIUM ITERATIONS MAY BE
       ADDED IN THE RESTART (NEQIT COMMAND) USING THE RESTART FILE file0.Rnnn                                                                                                                                                                                                                                                         

 ALL CURRENT MAPDL DATA WRITTEN TO FILE NAME= file.db
  FOR POSSIBLE RESUME FROM THIS POINT

 

 NUMBER OF WARNING MESSAGES ENCOUNTERED=         17
 NUMBER OF ERROR   MESSAGES ENCOUNTERED=          4

 

 ***** PROBLEM TERMINATED BY INDICATED ERROR(S) OR BY END OF INPUT DATA *****