ANSYS command problem re element death/element table postprocessing

[bzz77]

I am a new to ANSYS command-language mode. I am having trouble animating the procedure described below. The procedure is meant to model melting over time through element death (based on example from U. Alberta at www.mece.uAlberta.ca/tutorials/ansys/AT/BirthDeath/BirthDeath.html).

My problem is that I can't get the elements that exceed 600 C (my melting criterion) to disappear SEQUENTIALLY from the animation. Instead, I can only get those elements that exceed 600 C in EITHER the first or last step to disappear. The temperature contours evolve during the animation, but the melted/disappeared elements stay the same. I have tried writing a loop to make a new element table for each substep in which melted elements disappear, but this has not worked.

I would very much appreciate help with this...The postprocessing part of the code should appear in bold blue italics.



finish
/clear

/title, Transient melting by element death (conduction)
/prep7 ! Enter the preprocessor

! define geometry

BLC4,0,0,20,15 ! Create rectangle
BLC4,0,0,10,4 ! Create smaller rectangle (magma)
ASBA,1,2 ! Boolean Subtraction (subtracts area 2 (small) from area 1 (big))


ET,1,Plane55 ! Element type

MP,Dens,1,2262e9 ! Define density
mp,c,1,0.001604 ! Define specific heat
mp,kxx,1,0.001 ! Define heat transfer coefficient

! Mesh size
SMRT,6
CM,_Y,AREA
ASEL, , , , 3
CM,_Y1,AREA
CHKMSH,'AREA'
CMSEL,S,_Y

AMESH,_Y1 ! Mesh area

! Refine mesh
CMDEL,_Y
CMDEL,_Y1
CMDEL,_Y2

FLST,5,6,2,ORDE,4
FITEM,5,6
FITEM,5,22
FITEM,5,-25
FITEM,5,44
CM,_Y,ELEM
ESEL, , , ,P51X
CM,_Y1,ELEM
CMSEL,S,_Y
CMDEL,_Y


EREF,_Y1, , ,3,0,1,1
CMDEL,_Y1


finish
/solu ! Enter solution phase

antype,4 ! Transient analysis
nropt,full ! Newton Raphson - full

SOLCONTROL,ON,0

TUNIF,200,
TREF,200,

OUTPR,ALL,ALL,

OUTRES,ALL,ALL

time,3.1536e13 ! Time at end of analysis
AUTOTS,0
DELTIM,315360e6, , ,1 ! Time step
AUTOTS,0
KBC,1

TSRES,ERASE

TIME,31536000000000
AUTOTS,0
NSUBST,100, , ,1 ! Number of substeps,100
KBC,1


lumpm,0 ! Lumped mass off

neqit,100 ! Max no. of iterations
autots,off ! Auto time search off
lnsrch,on ! Line search on
kbc,1 ! Load applied in steps, not ramped

IC,all,temp,200 ! Initial conditions, temp = 200

PRED,-1
FLST,2,628,1,ORDE,2
FITEM,2,1
FITEM,2,-628
IC,P51X,TEMP,200,
FLST,2,2,4,ORDE,2
FITEM,2,6
FITEM,2,-7
/GO

DL,P51X, ,TEMP,1200,1 ! BC
FLST,2,2,4,ORDE,2
FITEM,2,2
FITEM,2,-3
/GO

DL,P51X, ,TEMP,200,1
SAVE
SAVE
SAVE
/STAT,SOLU
SOLVE

TIME,31536000000000
AUTOTS,-1
DELTIM,315360000000, , ,1
KBC,1

TSRES,ERASE

TIME,31536000000000
AUTOTS,-1
NSUBST,100, , ,1
KBC,1

TSRES,ERASE
/STAT,SOLU

solve
finish

/post1

set, first
etable,melty,temp, ! Create an element table
esel,s,etab,melty,600 ! Select all elements from table ! above 600
finish

/solu ! Re-enter solution phase
antype,,rest ! Restart analysis
ekill,all ! Kill all selected elements
esel,all ! Re-select all elements

finish

/post1 ! Re-enter postprocessor
set,first ! Read in last subset of data
esel,s,live ! Select all live elements
plnsol,temp ! Plot the temp contour of the live elements

!/CONT,1,10,200,100,1200
!PLNS,TEMP,
!/REPLOT

*DO, i,1,10,1
set,i
etable,delete
etable,melty,temp, ! Create an element table
esel,s,etab,melty,600 ! Select all elements from table ! above 600
finish

/solu ! Re-enter solution phase
antype,,rest ! Restart analysis
ekill,all ! Kill all selected elements
esel,all ! Re-select all elements

finish

/post1 ! Re-enter postprocessor
set,i ! Read in last subset of data
esel,s,live ! Select all live elements
plnsol,temp
/CONT,1,10,200,100,1200
PLNS,TEMP,
/replot

*ENDDO

ANTIME,100,0.5, ,0,2,0,0.31536E+14

 

[bzz77]

I'm a new user and realized my initial post wasn't very clear...I worked on the problem some more by incorporating some advice and think I'm on the right track, but still have a couple of problems. I would really appreciate any help. The code (below) now includes a loop for checking whether elements meet the melting/death criterion at each substep.

Although I have a SOLUTION, I still can't ANIMATE the element death/melting. Also, when I change parameters like the initial T or BC T, I get error messages saying that no elements have been selected. I also get errors when I try to change the time range of the calculation (I want total time to be ~1e13 for example). Here's the code:

/title, Convection Example
/prep7 ! Enter the preprocessor

! define geometry

k,1,0,0 ! Define keypoints
k,2,0.03,0
k,3,0.03,0.03
k,4,0,0.03
a,1,2,3,4 ! Connect the keypoints to form area


! mesh 2D areas

ET,1,Plane55 ! Element type

MP,Dens,1,2262e9 ! Define density
mp,c,1,0.001604 ! Define specific heat
mp,kxx,1,1.8 ! Define heat transfer coefficient

esize,0.0025 ! Mesh size
amesh,all ! Mesh area

finish


/solu ! Enter solution phase

antype,4 ! Transient analysis

tot_time = 1e6
t_steps = 10
time_inc = tot_time/t_steps

time,1e6 ! Time at end of analysis

nropt,full ! Newton Raphson - full
lumpm,0 ! Lumped mass off
nsubst,10 ! Number of substeps, 20
neqit,10 ! Max no. of iterations
autots,off ! Auto time search off
lnsrch,on ! Line search on


TUNIF,200,
IC,all,temp,200 ! Initial conditions, temp = 200

*do, i,1 ,10, 1
/solu
time=i*time_inc
nsub, 1
outres,all,all ! Output data for all substeps

!... any stuff about boundary conditions ...

! fixed temp BC's
nsel,s,ext ! Node select all exterior nodes
sf,all,conv,10,1200
NSEL,ALL ! Reselect all nodes
kbc,1 ! Load applied in steps, not ramped
/gst,off ! Turn off graphical convergence monitor

solve
finish

/post1
set, last
etable,melty,temp, ! Create an element table
esel,s,etab,melty,200 ! Select all elements from table above 200
finish
/solu ! Re-enter solution phase
antype,,rest ! Restart analysis
ekill,all ! Kill all selected elements
esel,all

!*enddo

/post1 ! Re-enter postprocessor
set,last ! Read in last subset of data
esel,s,live ! Select all live elements
plnsol,temp ! Plot the temp contour of the live elements
/seg,delete
/seg,multi,anm1,.1
/CONT,1,10,200,100,1200

!PLNS,TEMP,
/REPLOT

*enddo
/post1
/seg,off
ANTIME,20,0.5, ,0,2,200,1200