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How to carry out nonlinear iterative contact subroutine in SOL101 only on subset of subcases if possible?

I want to run contact subroutine in a linear elastic SOL101 and therefore defined the cards
  • 1xBCONPRG with ICOORD=1 (Stress free Initial state), ISEARCH=1 (Search only from Slave to Master)
  • 2x BCBODY1, both 3D and Deformable
  • 2x BCPROP
  • 1x BCONECT assigning slave and master and referencing the Parameter set
  • 1x BCTABL1 with ID=99 referencing a single BCONECT
 
As I want to run contact subroutine only on a subset of the subcases, I set BCONTACT=99 on the subcases that should iterate out the contact and BCONTACT=NONE on all other subcases.
 
The nonlinear Iteration is still carried out for each subcase.
  • Is it possible to run the nonlinear subroutine only for certain subcases
  • If yes, how to set the Parameters to do so?
  • SOL 101 is linear and only nonlinearity supported is the contact. Sol 101 does allow for contact conditions to change from subcase to subcase. Please refer to BCONTACT case control entry description. These subcases in sol101 are independent solutions. If you like , later subcase to be dependent or starting from the prior subcase you would want to use SOL400 step definitions.
  • I doubt that this is possible at all.
    I use this: No NLSTEP in SC1: Default 10 inc, NLSTEP with lcnt in SC2: 1 inc
     
    Still nonlinear, but with a minimum of iterations.
     
    SUBCASE 1
    $ Subcase name : Default
      SUBTITLE=Default
      $ NLSTEP = 1
      BCONTACT = 1
      SPC = 2
      LOAD = 3
    SUBCASE 2
    $ Subcase name : Default
      SUBTITLE=Default
      NLSTEP = 1
      BCONTACT = 1
      SPC = 2
      LOAD = 3
      DISPLACEMENT(PLOT,SORT1,REAL)=ALL
      $ SPCFORCES(PLOT,SORT1,REAL)=ALL
      $ STRESS(PLOT,SORT1,REAL,VONMISES,BILIN)=ALL
    BEGIN BULK
    PARAM  PRTMAXIM YES
    BCPARA ,0
           ,NLGLUE,0
           ,FTYPE,6
           ,METHOD,segtoseg
           ,ERRBAS,1      $ Pair Contact Tolerance, Prio 2
           ,ERROR,.01     $ Global Contact Tolerance, Prio 3
    $
    NLSTEP,1
           ,lcnt,1
     
     
     
    STS:
     
     
     subcase     inc cycl sepa cut    cycl
     /step #      #    #   #   #       #
          1         |--of the inc--|--------
          0       0    0   0   0       0
          0       1    3   0   0       3
          0       2    2   0   0       5
          0       3    2   0   0       7
          0       4    2   0   0       9
          0       5    2   0   0      11
          0       6    2   0   0      13
          0       7    2   0   0      15
          0       8    2   0   0      17
          0       9    2   0   0      19
          0      10    2   0   0      21
     
     subcase     inc cycl sepa cut    cycl
     /step #      #    #   #   #       #
          2         |--of the inc--|--------
          0       0    0   0   0       0
          0       1    4   0   0       4
     
     
  • @Sanjay Patel​ ​: I also interpreted the Manual in the way, you described and that contact can change from subcase to subcase. This is also the reason why I set my Parameters in the way I described above. Could you enrich your answer with how to do it and what is wrong with the way I described above?
     
    @Karl Raedle​ : Are you sure, that running 1 NLSTEP is the same as the linear solution? Don't you get an unconverged solution from this setting?
     
    Please also have a look at the snippets below from the .f06 file. It seems that the solver starts solution for subcase 1190 and within this solution it iterates out also all other load cases. Focus especially on the header of snippet 2 saying subcase 1190 first, and then in the second line subcase 1230.
     
    Snippet 1:
    -----------------------------
    0    9.0G FORWARD -X                                                                                       SUBCASE 1190          
        STIFFNESS UPDATE TIME-1892160000.00 SECONDS                                       SUBCASE    1190         STEP       0
               ITERATION TIME         5.44 SECONDS
           LOAD NO.      - - ERROR FACTORS - -   CONV ITR MAT NO.   AVG    TOTL      - - - - - DISP - - - - - - LINE_S NO. TOT TOT
           STEP INC ITR DISP    LOAD     WORK  RATE DIV DIV BIS R_FORCE  WORK     AVG       MAX    AT GRID C FACT NO QNV KUD ITR
    %1.00000E-01  1 1 1.00E+00 6.46E-11 1.00E+00 1.000 2  1  0 2.24E-03-1.648E-01 2.78E-02 2.138E-01  488705 2 1.00 0 0  0   1
     *** JOB CONVERGES FOR THE CURRENT STEP.
     *** SUBCASE  1190 STEP     0 IS COMPLETED.
    ----------------------------
     
    and after convergence of subcase 1190, it starts with another subcase, where I set BCONTACT=NONE
     
    Snippet 2
    ----------------------------
    0    9.0G FORWARD -X                                                                                       SUBCASE 1190          
        STIFFNESS UPDATE TIME-1892159872.00 SECONDS                                       SUBCASE    1230         STEP       0
               ITERATION TIME         3.49 SECONDS
           LOAD NO.      - - ERROR FACTORS - -   CONV ITR MAT NO.   AVG    TOTL      - - - - - DISP - - - - - - LINE_S NO. TOT TOT
           STEP INC ITR DISP    LOAD     WORK  RATE DIV DIV BIS R_FORCE  WORK     AVG       MAX    AT GRID C FACT NO QNV KUD ITR
    %1.00000E-01  1 1 1.00E+00 3.28E-10 1.00E+00 1.000 2  1  0 2.22E-03-1.547E+00 1.15E-02 1.949E-01  488988 3 1.00 0 0  0   1
     *** JOB CONVERGES FOR THE CURRENT STEP.
     *** SUBCASE  1230 STEP     0 IS COMPLETED.
    ---------------------------