Learning Forum

[John Miller]

Dear forum user,

I have a small problem with an undesired changing time step in a single frame restart calculation.
The time step suddenly jumps from 0.1 s to 1s (the default value) in the middle of the simulation.

After 11 load steps, the time increment jumps to 1 s.

Although I have set the time with Time, dt..... I have defined a time step of 0.1 s.
I have already tried to suppress the behaviour of the solver with "autots,off" at various points in the APDL snippet script, unfortunately without success.

With best regards

John MIller

[John Miller]

 

 

I use single frame restart, therefore the restart database should be the first load step

but the solver output indicates something is wrong. In the 12th step something is changing the time step from 0,1s to 1s

*** ANSYS GLOBAL STATUS ***

 

 TITLE = ConvRadSURF152Test–Thermisch-transient (E5)                         

 ANALYSIS TYPE =  TRANSIENT           

 NUMBER OF ELEMENT TYPES =      5

     17120 ELEMENTS CURRENTLY SELECTED.  MAX ELEMENT NUMBER =       21920

     58666 NODES CURRENTLY SELECTED.     MAX NODE NUMBER =          58666

        17 COMPONENTS CURRENTLY DEFINED

 MAXIMUM LINEAR PROPERTY NUMBER        =       2

 MAXIMUM REAL CONSTANT SET NUMBER      =       4

 ACTIVE COORDINATE SYSTEM              =       0  (CARTESIAN) 

 NUMBER OF SPECIFIED CONSTRAINTS       =   31087

 NUMBER OF SPECIFIED SURFACE LOADS     =    3520

 CURRENT LOAD CASE =      0 OF      0

 LOAD SET   =       1

 SUBSTEP    =       1

 TIME/FREQ  =   0.10000   

 

 INITIAL JOBNAME = file

 CURRENT JOBNAME = file

 

 RESTART PROCEDURE RE-BUILDS BOUNDARY CONDITIONS

 AND LOADING INFO UPTO THE CURRENT LOADSTEP

 

 READ ANSYS LOADS DATA FROM FILE= file.ldhi                                                                                                                                                                                                                                                           

 

 DELETE SOLID MODEL BOUNDARY CONDITIONS

 

….

 SOLUTION MONITORING INFO IS WRITTEN TO FILE= file.mntr                                                                                                                                                                                                                                                           

 

 *** LOAD STEP    11   SUBSTEP     1  COMPLETED.    CUM ITER =     11

 *** TIME =   1.10000         TIME INC =  0.100000      NEW TRIANG MATRIX

 *** RESPONSE EIGENVALUE =  796.3       OSCILLATION LIMIT =  79.63   

 

 FINISH SOLUTION PROCESSING

 

 

 ***** ROUTINE COMPLETED *****  CP =        34.109

 

 

 

 

*** ANSYS GLOBAL STATUS ***

 

 TITLE = ConvRadSURF152Test–Thermisch-transient (E5)                          

 ANALYSIS TYPE =  TRANSIENT           

 NUMBER OF ELEMENT TYPES =      5

     17120 ELEMENTS CURRENTLY SELECTED.  MAX ELEMENT NUMBER =       21920

     58666 NODES CURRENTLY SELECTED.     MAX NODE NUMBER =          58666

        17 COMPONENTS CURRENTLY DEFINED

 MAXIMUM LINEAR PROPERTY NUMBER        =       2

 MAXIMUM REAL CONSTANT SET NUMBER      =       4

 ACTIVE COORDINATE SYSTEM              =       0  (CARTESIAN) 

 NUMBER OF SPECIFIED CONSTRAINTS       =   31087

 NUMBER OF SPECIFIED SURFACE LOADS     =    3520

 CURRENT LOAD CASE =      0 OF      0

 LOAD SET   =       1

 SUBSTEP    =       1

 TIME/FREQ  =   0.10000   

 

 INITIAL JOBNAME = file

 CURRENT JOBNAME = file

 

 RESTART PROCEDURE RE-BUILDS BOUNDARY CONDITIONS

 AND LOADING INFO UPTO THE CURRENT LOADSTEP

 

 READ ANSYS LOADS DATA FROM FILE= file.ldhi                                                                                                                                                                                                                                                           

 

 DELETE SOLID MODEL BOUNDARY CONDITIONS

 

 NUMBER OF NODAL CONSTRAINTS DELETED                       =     31087

 NUMBER OF ELEMENT CONVECTIONS/HEAT FLUXES DELETED         =      1760

 

 *** NOTE ***                            CP =      34.953   TIME= 06:49:36

 The number of results set on the restart command is the last set on the

 RTH file.  No updating for the RTH file is required.                   

 

 STEP BOUNDARY CONDITION KEY= 1

 

 REFERENCE TEMPERATURE=   0.000  (TUNIF=  25.000)

 

 INERTIA RELIEF KEY=  0

 

 UNIFORM TEMPERATURE SET TO   25.0000000   

 

 ACEL=    0.0000      0.0000      0.0000   

 

 OMEGA=  0.0000      0.0000      0.0000   

 

 DOMEGA=  0.0000      0.0000      0.0000   

 

 CGLOC=  0.0000      0.0000      0.0000   

 

 CGOMGA=  0.0000      0.0000      0.0000   

 

 DCGOMG=  0.0000      0.0000      0.0000   

 

 SPECIFIED CONSTRAINT TEMP FOR SELECTED NODES            1 TO           1 BY           1

 REAL=  30.0000000       IMAG=  0.00000000   

 

 SPECIFIED CONSTRAINT TEMP FOR SELECTED NODES            2 TO           2 BY           1

 REAL=  30.0000000       IMAG=  0.00000000   

 

 

…

SPECIFIED CONSTRAINT TEMP FOR SELECTED NODES        47685 TO       47685 BY           1

 REAL=  70.0000000       IMAG=  0.00000000   

 

 SPECIFIED CONSTRAINT TEMP FOR SELECTED NODES        47686 TO       47686 BY           1

 REAL=  70.0000000       IMAG=  0.00000000   

 

 NONE SELECT  FOR ITEM=NODE COMPONENT=   

  IN RANGE         1 TO      58666 STEP          1

 

          0  NODES (OF      58666  DEFINED) SELECTED BY NSEL  COMMAND.

 

 NONE SELECT  FOR ITEM=ELEM COMPONENT=   

  IN RANGE         1 TO      21920 STEP          1

 

          0  ELEMENTS (OF      17120  DEFINED) SELECTED BY ESEL  COMMAND.

 

 *** WARNING ***                         CP =      36.891   TIME= 06:49:38

 Entity 100 is undefined.  The ESEL command is ignored.                 

 

*** ANSYS – ENGINEERING ANALYSIS SYSTEM  RELEASE 2021 R2          21.2     ***

 Ansys Mechanical Enterprise Academic Teaching    

 00000000  VERSION=WINDOWS x64   06:49:39  MAR 25, 2023 CP=     37.094

 

 ConvRadSURF152Test–Thermisch-transient (E5)                                 

 

 

 

 *** WARNING ***                         CP =      37.109   TIME= 06:49:39

 Material number 5 (used by element 20161) should normally have at least

 one MP or one TB type command associated with it.  Output of energy by 

 material may not be available.                                         

 

 *** ANSYS – ENGINEERING ANALYSIS SYSTEM  RELEASE 2021 R2          21.2     ***

 Ansys Mechanical Enterprise Academic Teaching    

 00000000  VERSION=WINDOWS x64   06:49:39  MAR 25, 2023 CP=     37.375

 

 ConvRadSURF152Test–Thermisch-transient (E5)                                 

 

 

 

 SOLUTION MONITORING INFO IS WRITTEN TO FILE= file.mntr                                                                                                                                                                                                                                                           

 

 *** LOAD STEP    12   SUBSTEP     1  COMPLETED.    CUM ITER =     12

 *** TIME =   2.10000         TIME INC =   1.00000      NEW TRIANG MATRIX

 *** RESPONSE EIGENVALUE =  1298.       OSCILLATION LIMIT =  1298.   

 

 FINISH SOLUTION PROCESSING

 

 

 ***** ROUTINE COMPLETED *****  CP =        39.297