Learning Forum

[John Miller]

Hello,

I'm struggeling with the esel command. In the simulation I create surface elements at the external nodes of an workpiece within the /prep7, then I go back to the /solu. A single frame restart analysis:

Time,i*dt
solve

save,file,db

/prep7
/GOPR 
/com,!------------------------------------------------------------------------
/com,Start surf152
   esel,s,ename,,surf152            ! Element selection of surf152 elements
   cm,ELsurf152,elements         ! Create a component which includes surf152 elements
   edele,ELsurf152                    ! Deletion of former surf152 elements

   et,100,152
   keyopt,100,4,1
   keyopt,100,5,0
   keyopt,100,8,1

   cmsel,s,external,node
   esln,all
   type,100
   esurf
   esel,none
   
   esel,s,type,,100
   esel,stat
   esel,s,ename,,152
   esel,stat
   cm,surfElem152,elem
   esel,stat
   
   allsel,all
   outres,all
save,file,db
/com,Ende surf152
/com,!------------------------------------------------------------------------
/solu
  trnopt,full
  nropt,full
  thopt,full
  
save,file,db  

  antype,,restart
/com,!------------------------------------------------------------------------
/com, Start surf152
  nsel,none
  esel,none
  cm,surfElem152,elem
  esel,stat
  sfe,surfElem152,1,hflux,,hflux_test
/com, Ende surf152 
/com,!------------------------------------------------------------------------

  allsel,all
  outres,all,all
*enddo 

 

The solver output is :

*** LOAD STEP     1   SUBSTEP     1  COMPLETED.    CUM ITER =      1
 *** TIME =  0.100000         TIME INC =  0.100000      NEW TRIANG MATRIX
 *** RESPONSE EIGENVALUE =  67.99       OSCILLATION LIMIT =  6.799   

 *** ANSYS BINARY FILE STATISTICS
  BUFFER SIZE USED= 16384
        4.688 MB WRITTEN ON ELEMENT SAVED DATA FILE: file.esav
        3.812 MB WRITTEN ON ASSEMBLED MATRIX FILE: file.full
        5.500 MB WRITTEN ON RESULTS FILE: file.rth

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

 FINISH SOLUTION PROCESSING

 ***** ROUTINE COMPLETED *****  CP =         1.250

 *** ANSYS - ENGINEERING ANALYSIS SYSTEM  RELEASE 2021 R2          21.2     ***
 Ansys Mechanical Enterprise Academic Teaching    
 00000000  VERSION=WINDOWS x64   22:10:36  MAR 24, 2023 CP=      1.250

 ConvRadSURF152Test--Thermisch-transient (B5)                                 

          ***** ANSYS ANALYSIS DEFINITION (PREP7) *****
 !------------------------------------------------------------------------------
 Start surf152

 SELECT       FOR ITEM=ENAM COMPONENT=   
  IN RANGE       152 TO        152 STEP          1

       1280  ELEMENTS (OF       6720  DEFINED) SELECTED BY  ESEL  COMMAND.

 DEFINITION OF COMPONENT = ELSURF152  ENTITY=ELEM

 *** WARNING ***                         CP =       1.250   TIME= 22:10:36
 Assembly ELSURF152 is deleted.                                         

 ELEMENT TYPE        100 IS SURF152      3-D THERMAL SURFACE        
  KEYOPT( 1- 6)=        0      0      0        0      0      0
  KEYOPT( 7-12)=        0      0      0        0      0      0
  KEYOPT(13-18)=        0      0      0        0      0      0

 CURRENT NODAL DOF SET IS  TEMP
  THREE-DIMENSIONAL MODEL

 ELEMENT TYPE     100 IS SURF152      3-D THERMAL SURFACE        
  KEYOPT( 1- 6)=        0      0      0        1      0      0
  KEYOPT( 7-12)=        0      0      0        0      0      0
  KEYOPT(13-18)=        0      0      0        0      0      0

 CURRENT NODAL DOF SET IS  TEMP
  THREE-DIMENSIONAL MODEL

 ELEMENT TYPE     100 IS SURF152      3-D THERMAL SURFACE        
  KEYOPT( 1- 6)=        0      0      0        1      0      0
  KEYOPT( 7-12)=        0      0      0        0      0      0
  KEYOPT(13-18)=        0      0      0        0      0      0

 CURRENT NODAL DOF SET IS  TEMP
  THREE-DIMENSIONAL MODEL

 ELEMENT TYPE     100 IS SURF152      3-D THERMAL SURFACE        
  KEYOPT( 1- 6)=        0      0      0        1      0      0
  KEYOPT( 7-12)=        0      1      0        0      0      0
  KEYOPT(13-18)=        0      0      0        0      0      0

 CURRENT NODAL DOF SET IS  TEMP
  THREE-DIMENSIONAL MODEL

 SELECT      COMPONENT EXTERNAL                       

 SELECT      ALL ELEMENTS HAVING ANY NODE IN NODAL SET.

        138 ELEMENTS (OF       5440  DEFINED) SELECTED FROM
      225 SELECTED NODES BY  ESLN COMMAND.

 ELEMENT TYPE SET TO       100

 GENERATE ELEMENTS ON SURFACE DEFINED BY SELECTED NODES
  TYPE=      100  REAL=        1  MATERIAL=        1  ESYS=    0

 NUMBER OF ELEMENTS GENERATED=         12                        

 NONE SELECT  FOR ITEM=ELEM COMPONENT=    
  IN RANGE         1 TO       9100 STEP          1

          0  ELEMENTS (OF       5452  DEFINED) SELECTED BY ESEL  COMMAND.

 SELECT       FOR ITEM=TYPE COMPONENT=   
  IN RANGE       100 TO        100 STEP          1

         12  ELEMENTS (OF       5452  DEFINED) SELECTED BY  ESEL  COMMAND.

 ****** STATUS OF ELEMENTS ******
 NUMBER OF SELECTED ELEMENTS=        12
 NUMBER OF DEFINED ELEMENTS=       5452
 MAXIMUM ELEMENT NUMBER=           9100

 SELECT       FOR ITEM=ENAM COMPONENT=   
  IN RANGE       152 TO        152 STEP          1

         12  ELEMENTS (OF       5452  DEFINED) SELECTED BY  ESEL  COMMAND.

 ****** STATUS OF ELEMENTS ******
 NUMBER OF SELECTED ELEMENTS=        12
 NUMBER OF DEFINED ELEMENTS=       5452
 MAXIMUM ELEMENT NUMBER=           9100

 DEFINITION OF COMPONENT = SURFELEM152  ENTITY=ELEM

 ****** STATUS OF ELEMENTS ******
 NUMBER OF SELECTED ELEMENTS=        12
 NUMBER OF DEFINED ELEMENTS=       5452
 MAXIMUM ELEMENT NUMBER=           9100

 SELECT ALL ENTITIES OF TYPE= ALL  AND BELOW

 WRITE ALL  ITEMS TO THE DATABASE WITH A FREQUENCY OF LAST
   FOR ALL APPLICABLE ENTITIES

 ALL CURRENT ANSYS DATA WRITTEN TO FILE NAME= file.db
  FOR POSSIBLE RESUME FROM THIS POINT
 Ende surf152
 !------------------------------------------------------------------------------


 ***** ROUTINE COMPLETED *****  CP =         1.328



 *****  ANSYS SOLUTION ROUTINE  *****

 PERFORM A FULL TRANSIENT ANALYSIS
  USING NEWMARK ALGORITHM

 USE THE FULL NEWTON-RAPHSON OPTION FOR  ALL DEGREES OF FREEDOM
   AND USE THE DEFAULT ADAPTIVE DESCENT OPTION

 Use Full Nonlinear Thermal Transient Solution

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


 PERFORM A TRANSIENT ANALYSIS
  RESTART PREVIOUSLY RUN ANALYSIS TO ADD ADDITIONAL LOAD STEPS
  RESTART WILL BE CONTINUED WITH EXISTING LOADSTEP
  RESTART WILL BE PERFORMED BASED ON:
   PREVIOUS LOADSTEP =      1 SUBSTEP =      1

 RESUME ANSYS DATA FROM FILE NAME=file.rdb                                                                                                                                                                                                                                                           
     DO NOT PLOT ANYTHING

 *** ANSYS GLOBAL STATUS ***

 TITLE = ConvRadSURF152Test--Thermisch-transient (B5)                         
 ANALYSIS TYPE =  TRANSIENT           
 NUMBER OF ELEMENT TYPES =      5
      6720 ELEMENTS CURRENTLY SELECTED.  MAX ELEMENT NUMBER =        9088
     21662 NODES CURRENTLY SELECTED.     MAX NODE NUMBER =          21662
        17 COMPONENTS CURRENTLY DEFINED
 MAXIMUM LINEAR PROPERTY NUMBER        =       2
 MAXIMUM REAL CONSTANT SET NUMBER      =       4
 ACTIVE COORDINATE SYSTEM              =       0  (CARTESIAN) 
 NUMBER OF SPECIFIED CONSTRAINTS       =   15738
 NUMBER OF SPECIFIED SURFACE LOADS     =    2560
 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                       =     15738
 NUMBER OF ELEMENT CONVECTIONS/HEAT FLUXES DELETED         =      1280

 *** NOTE ***                            CP =       1.625   TIME= 22:10:37
 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.                   
 !------------------------------------------------------------------------------
  Start surf152

 NONE SELECT  FOR ITEM=NODE COMPONENT=   
  IN RANGE         1 TO      21662 STEP          1

          0  NODES (OF      21662  DEFINED) SELECTED BY NSEL  COMMAND.

 NONE SELECT  FOR ITEM=ELEM COMPONENT=   
  IN RANGE         1 TO       9088 STEP          1

          0  ELEMENTS (OF       6720  DEFINED) SELECTED BY ESEL  COMMAND.

 DEFINITION OF COMPONENT = SURFELEM152  ENTITY=ELEM

 ****** STATUS OF ELEMENTS ******
 NUMBER OF SELECTED ELEMENTS=         0
 NUMBER OF DEFINED ELEMENTS=       6720
 MAXIMUM ELEMENT NUMBER=           9088

 SPECIFIED SURFACE LOAD HFLU FOR ALL PICKED ELEMENTS  LKEY = 1
     VALUES =     500.00         500.00         500.00         500.00   
  Ende surf152
 !------------------------------------------------------------------------------

 

 

The output shows 12 surf152 elements are created in /prep7, but I can't select them with esel in the /solu after restart.

 I don't know why

 

 

With best regards

 

John Miller

[Mike Rife]

Hi John

In the restart you accidentally redefined the component surfElem152 with no elements selected.  So it is an empty component.  I think that is a mistake...as is selecting none for nodes/elements prior.  Just issue the SFE command with the component name...no need for selecting some subset.  MIke

 

[John Miller]

Hi Mike,

thanks for the help.

I change the code regarding your advice, but unfortunately, something is still wrong.

 

Time,….

solve

 

save,file,db

 

/prep7

/GOPR

/com,!---------------------------------------------------------------------------------------------------------------------!

/com,Start creation of surf152 for convection and radiation

   esel,s,ename,,152             ! Element selection of surf152 elements

   cm,ELsurf152,elements         ! Create a component which includes surf152 elements

   edele,ELsurf152               ! Deletion of former surf152 elements

 

   et,100,152

   keyopt,100,4,1

   keyopt,100,5,0

   keyopt,100,8,1

 

   cmsel,s,external,node

   esln,all

   type,100

   esurf

   esel,none

  

   esel,s,type,,100

   esel,stat

   esel,s,ename,,152

   esel,stat

   cm,surfElem152,elem

   esel,stat

  

   allsel,all

   outres,all

save,file,db

/com,End creation of surf152 for convection and radiation

/com,!---------------------------------------------------------------------------------------------------------------------!

/solu

  trnopt,full

  nropt,full

  thopt,full

 

save,file,db 

 

  antype,,restart

/com,!---------------------------------------------------------------------------------------------------------------------!

/com, Start surf152 selection for thermal load

!  cm,surfElem152,elem

  nsel,stat

  esel,stat

  sfe,all,1,conv,2,Tbulk

/com, End surf152 selection for thermal load

/com,!---------------------------------------------------------------------------------------------------------------------!

 

  allsel,all

  outres,all,all

*enddo

 

The solver output is indicating that 6720 Elements are selected, but in the /prep7 I created 12 surface elements.

 

         ***** ANSYS ANALYSIS DEFINITION (PREP7) *****
 !------------------------------------------------------------------------------
 Start creation of surf152 for convection and radiation

 SELECT       FOR ITEM=ENAM COMPONENT=   
  IN RANGE       152 TO        152 STEP          1

       1280  ELEMENTS (OF       6720  DEFINED) SELECTED BY  ESEL  COMMAND.

 DEFINITION OF COMPONENT = ELSURF152  ENTITY=ELEM

 *** WARNING ***                         CP =       1.281   TIME= 09:23:28
 Assembly ELSURF152 is deleted.                                         

 ELEMENT TYPE        100 IS SURF152      3-D THERMAL SURFACE        
  KEYOPT( 1- 6)=        0      0      0        0      0      0
  KEYOPT( 7-12)=        0      0      0        0      0      0
  KEYOPT(13-18)=        0      0      0        0      0      0

 CURRENT NODAL DOF SET IS  TEMP
  THREE-DIMENSIONAL MODEL

 ELEMENT TYPE     100 IS SURF152      3-D THERMAL SURFACE        
  KEYOPT( 1- 6)=        0      0      0        1      0      0
  KEYOPT( 7-12)=        0      0      0        0      0      0
  KEYOPT(13-18)=        0      0      0        0      0      0

 CURRENT NODAL DOF SET IS  TEMP
  THREE-DIMENSIONAL MODEL

 ELEMENT TYPE     100 IS SURF152      3-D THERMAL SURFACE        
  KEYOPT( 1- 6)=        0      0      0        1      0      0
  KEYOPT( 7-12)=        0      0      0        0      0      0
  KEYOPT(13-18)=        0      0      0        0      0      0

 CURRENT NODAL DOF SET IS  TEMP
  THREE-DIMENSIONAL MODEL

 ELEMENT TYPE     100 IS SURF152      3-D THERMAL SURFACE        
  KEYOPT( 1- 6)=        0      0      0        1      0      0
  KEYOPT( 7-12)=        0      1      0        0      0      0
  KEYOPT(13-18)=        0      0      0        0      0      0

 CURRENT NODAL DOF SET IS  TEMP
  THREE-DIMENSIONAL MODEL

 SELECT      COMPONENT EXTERNAL                       

 SELECT      ALL ELEMENTS HAVING ANY NODE IN NODAL SET.

        138 ELEMENTS (OF       5440  DEFINED) SELECTED FROM
      225 SELECTED NODES BY  ESLN COMMAND.

 ELEMENT TYPE SET TO       100

 GENERATE ELEMENTS ON SURFACE DEFINED BY SELECTED NODES
  TYPE=      100  REAL=        1  MATERIAL=        1  ESYS=    0

 NUMBER OF ELEMENTS GENERATED=         12                        

 NONE SELECT  FOR ITEM=ELEM COMPONENT=   
  IN RANGE         1 TO       9100 STEP          1

          0  ELEMENTS (OF       5452  DEFINED) SELECTED BY ESEL  COMMAND.

 SELECT       FOR ITEM=TYPE COMPONENT=   
  IN RANGE       100 TO        100 STEP          1

         12  ELEMENTS (OF       5452  DEFINED) SELECTED BY  ESEL  COMMAND.

 ****** STATUS OF ELEMENTS ******
 NUMBER OF SELECTED ELEMENTS=        12
 NUMBER OF DEFINED ELEMENTS=       5452
 MAXIMUM ELEMENT NUMBER=           9100

 SELECT       FOR ITEM=ENAM COMPONENT=   
  IN RANGE       152 TO        152 STEP          1

         12  ELEMENTS (OF       5452  DEFINED) SELECTED BY  ESEL  COMMAND.

 ****** STATUS OF ELEMENTS ******
 NUMBER OF SELECTED ELEMENTS=        12
 NUMBER OF DEFINED ELEMENTS=       5452
 MAXIMUM ELEMENT NUMBER=           9100

 DEFINITION OF COMPONENT = SURFELEM152  ENTITY=ELEM

 ****** STATUS OF ELEMENTS ******
 NUMBER OF SELECTED ELEMENTS=        12
 NUMBER OF DEFINED ELEMENTS=       5452
 MAXIMUM ELEMENT NUMBER=           9100

 SELECT ALL ENTITIES OF TYPE= ALL  AND BELOW

 WRITE ALL  ITEMS TO THE DATABASE WITH A FREQUENCY OF LAST
   FOR ALL APPLICABLE ENTITIES

 ALL CURRENT ANSYS DATA WRITTEN TO FILE NAME= file.db
  FOR POSSIBLE RESUME FROM THIS POINT
 End creation of surf152 for convection and radiation
 !------------------------------------------------------------------------------


 ***** ROUTINE COMPLETED *****  CP =         1.375



 *****  ANSYS SOLUTION ROUTINE  *****

 PERFORM A FULL TRANSIENT ANALYSIS
  USING NEWMARK ALGORITHM

 USE THE FULL NEWTON-RAPHSON OPTION FOR  ALL DEGREES OF FREEDOM
   AND USE THE DEFAULT ADAPTIVE DESCENT OPTION

 Use Full Nonlinear Thermal Transient Solution

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


 PERFORM A TRANSIENT ANALYSIS
  RESTART PREVIOUSLY RUN ANALYSIS TO ADD ADDITIONAL LOAD STEPS
  RESTART WILL BE CONTINUED WITH EXISTING LOADSTEP
  RESTART WILL BE PERFORMED BASED ON:
   PREVIOUS LOADSTEP =      1 SUBSTEP =      1

 RESUME ANSYS DATA FROM FILE NAME=file.rdb                                                                                                                                                                                                                                                           
     DO NOT PLOT ANYTHING

 *** ANSYS GLOBAL STATUS ***

 TITLE = ConvRadSURF152Test--Thermisch-transient (B5)                         
 ANALYSIS TYPE =  TRANSIENT           
 NUMBER OF ELEMENT TYPES =      5
      6720 ELEMENTS CURRENTLY SELECTED.  MAX ELEMENT NUMBER =        9088
     21662 NODES CURRENTLY SELECTED.     MAX NODE NUMBER =          21662
        17 COMPONENTS CURRENTLY DEFINED
 MAXIMUM LINEAR PROPERTY NUMBER        =       2
 MAXIMUM REAL CONSTANT SET NUMBER      =       4
 ACTIVE COORDINATE SYSTEM              =       0  (CARTESIAN) 
 NUMBER OF SPECIFIED CONSTRAINTS       =   15738
 NUMBER OF SPECIFIED SURFACE LOADS     =    2560
 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                       =     15738
 NUMBER OF ELEMENT CONVECTIONS/HEAT FLUXES DELETED         =      1280

 *** NOTE ***                            CP =       1.672   TIME= 09:23:28
 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.                   
 !------------------------------------------------------------------------------
  Start surf152 selection for thermal load

 ****** STATUS OF NODES ******
 NUMBER OF SELECTED NODES=     21662
 NUMBER OF DEFINED NODES=      21662
 MAXIMUM NODE NUMBER=          21662

 ****** STATUS OF ELEMENTS ******
 NUMBER OF SELECTED ELEMENTS=      6720
 NUMBER OF DEFINED ELEMENTS=       6720
 MAXIMUM ELEMENT NUMBER=           9088

 SPECIFIED SURFACE LOAD CONV FOR ALL SELECTED ELEMENTS  LKEY = 1   KVAL = 2
     VALUES =     25.000         25.000         25.000         25.000   

 *** WARNING ***                         CP =       1.672   TIME= 09:23:28
 Some of the defined and selected elements did not require convections. 
 Use the SFELIST,ALL,CONV command to view a list of elements that did   
 have convections stored.                                               
  End surf152 selection for thermal load
 !------------------------------------------------------------------------------

 

 

I don’t get it, seems it’s not possible to pick the surface elements created in /prep7 in /solu .

 

With best regards

John

 

[Mike Rife]

John

Check the output - the restart database is being resumed (file.rdb) after you resumed the saved database.  The restart db does not contain the changes you made to the FEM.

What is the point of redoing the surface effect elements in this model?  Perhaps we need to step back and assess the overall workflow.

Mike

[John Miller]

Hello Mike,

I need the surface elements for an AM simulation. During the extrusion process, the elements are partially external and become after they are covered with the new layer internal. As you can see in the pictures

 

It’s not possible to apply radiation with GUI, because the external surface will match the finished workpiece shape after the building is done. Elements are external and become internal and so on. Application of convection via external nodes is easy, but radiation is the problem.

I thought surface elements could be the solution to this issue. Unfortunately, multi-frame restart is not possible in ansys transient thermal and a coupled thermal structural simulation is too time-consuming.

If it’s not possible to select the surf152 elements in /solu after creation in /prep7 and a single frame restart, the whole simulation is impossible.

With best regards

John