Help with Birth and Death and other stuff
Help with Birth and Death and other stuff
(OP)
Hello again!
I am having some problems regarding my thesis' simulation, so I am looking forward to any help! I have some questions that I am about to make, but first, I think I should explain what I am trying to do:
I want to simulate what we call butt-welding, so I have to plot many weld beads, side by side, and then some above them. I will use a moving heat source to simulate the welding arc, which inputs heat to the plate. The moving heat source is already working, but I need some help to continue this work.
1) Using Birth and Death (EALIVE and EKILL)
I am having some problem with this part. The ideal thing would be to plot the weld bead as the heat source moves, or/and when its elements achieve around 1450 °C (Fe-C steel fusion temperature, for a SAE 1020 or around it). I tried a snippet I've found on the internet but it doesn't works, or I am not using it right. My code is shown below, followed by the Birth and Death snippet I've found.
Here's the snippet
How can I make this work? Have you any other idea?
2) I simply can't position the heat source in any other coordinate system other than the global one, I don't know why, and I really need to know how to! The heat source always starts in (0,0,0) from the global coordinate system, and moves through the Z coordinate, as it should, but I can't make the heat source start from any other coordinate system... any clue?
3) How can I make a convection as a function of the temperature? Or how can I make a heat loss based on the temperature of the plate?
Any help would be REALLY, REALLY APPRECIATED!
Thanks in advance!
I am having some problems regarding my thesis' simulation, so I am looking forward to any help! I have some questions that I am about to make, but first, I think I should explain what I am trying to do:
I want to simulate what we call butt-welding, so I have to plot many weld beads, side by side, and then some above them. I will use a moving heat source to simulate the welding arc, which inputs heat to the plate. The moving heat source is already working, but I need some help to continue this work.
1) Using Birth and Death (EALIVE and EKILL)
I am having some problem with this part. The ideal thing would be to plot the weld bead as the heat source moves, or/and when its elements achieve around 1450 °C (Fe-C steel fusion temperature, for a SAE 1020 or around it). I tried a snippet I've found on the internet but it doesn't works, or I am not using it right. My code is shown below, followed by the Birth and Death snippet I've found.
CODE --> APDL
ET,1,SOLID70 CMSEL,ALL *GET,EMAX,ELEM,,NUM,MAX *GET,EMIN,ELEM,,NUM,MIN ALLSEL AUTOTS,ON TIME_WELD=200 DT=1 A=0.003 !A, B and C's are the heat source dimentions (meters) B=0.004 C1=0.004 C2=0.016 TAU=0 ! Time delay to control the heat source position at t0 (0 seconds) FF=0.4 ! FF and FR are the power distribution in the front side and rear side of the heat source, respectively FR=1.6 Q=3840 ! Power input (Watts) VEL=0.002 ! Welding speed EE=2.71 ! Euler number, I had to set it as 2.71 instead of using exp() due to some problems I was experiencing NPT=TIME_WELD/DT *DO,ii,1,NPT,1 WTIME=(ii/2) TIME,WTIME HCENTER=VEL*WTIME *DO,jj,EMIN,EMAX,1 X=CENTRX(jj) Y=CENTRY(jj) Z=CENTRZ(jj) CSI=Z+(VEL*(TAU-WTIME)) ! This is what controls the position of the heat source, through the axis Z, over time *IF,Z,GT,HCENTER,THEN ! Attributes C1 and FF to the front part of the heat source and C2 and FR to the rear side of the heat source C=C1 F=FF *ELSE C=C2 F=FR *ENDIF PART1=(6*(3**0.5)*Q*F)/(A*B*C*3.14*(3.14**0.5)) PART2=(EE**(-3*(X/A)**2))*(EE**(-3*(Y/B)**2))*(EE**(-3*((CSI/C)**2))) QF=PART1*PART2 ! Double ellipsoid heat source equation BFE,jj,HGEN,,QF *ENDDO OUTRES,ESOL,ALL, SOLVE *ENDDO CMSEL,ALL BFEDELE,ALL,ALL ALLSEL
CODE
/post1 ! Enter postprocessor set,last ! Read in last subset of data etable,melty,temp, ! Create an element table esel,s,etab,melty,1450 ! Select all elements from table above 1450 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,last ! Read in last subset of data esel,s,live ! Select all live elements plnsol,temp ! Plot the temp contour of the live elements
How can I make this work? Have you any other idea?
2) I simply can't position the heat source in any other coordinate system other than the global one, I don't know why, and I really need to know how to! The heat source always starts in (0,0,0) from the global coordinate system, and moves through the Z coordinate, as it should, but I can't make the heat source start from any other coordinate system... any clue?
3) How can I make a convection as a function of the temperature? Or how can I make a heat loss based on the temperature of the plate?
Any help would be REALLY, REALLY APPRECIATED!
Thanks in advance!




