热分析中，分布载荷问题。如何将加热源去除，计算保温过程。

easonxi

file:///D:/前二十秒.jpg

上面是第20秒的
file:///D:/第25秒.jpg
这是第25秒的
分析一个问题，想要把热源去除，实现保温过程。但是怎么搞都实现不了。望高手指点指点啊，拜谢！
我就是想在20秒到21秒的时候把下面的热源去除掉。然后再加上对流，计算5秒，可是怎么也实现不了，考虑过单元生死，但是没搞成功。希望高手指教啊！谢谢谢谢


这是命令流
/TITLE,FR4
h=0.00006
w=0.005
/PREP7
k,1,0,0,0
k,2,0,h,0
k,3,0,6*h,0
k,4,0,7*h,0
k,5,0,12*h,0
k,6,0,17*h,0
k,7,0,18*h,0
k,8,0,23*h,0
k,9,0,24*h,0
k,10,w,0,0
k,11,w,h,0
k,12,w,6*h,0
k,13,w,7*h,0
k,14,w,12*h,0
k,15,w,17*h,0
k,16,w,18*h,0
k,17,w,23*h,0
k,18,w,24*h,0
k,19,0.000125,0,0
k,20,0.000125,-0.001,0
k,21,0,-0.001,0!
k,22,0.000125,-0.0005,0
k,23,0.000425,0,0
k,24,0,-0.002,0
k,25,0.01,-0.002,0
k,26,0.01,0,0
a,1,2,11,10
a,2,3,12,11
a,3,4,13,12
a,4,5,14,13
a,5,6,15,14
a,6,7,16,15
a,7,8,17,16
a,8,9,18,17
a,1,19,20,21
a,22,23,19
a,21,24,25,26,23,22,20,21
mp,dens,1,8700
mp,kxx,1,400
mp,c,1,385
mp,dens,2,1900
mp,kxx,2,0.3
mp,c,2,1369
mp,dens,3,5765
mp,kxx,3,32.6
mp,c,3,213
mptemp,1,0,231,233,320
mpdata,enth,3,1,0,283655295,633452435,739208852
mpplot,enth,3,,,,,
et,1,plane55
esize,h
mshape,0,2d
mshkey,0
type,1
mat,1
real
amesh,1
amesh,3
amesh,6
amesh,8
amesh,9
type,1
mat,2
real
amesh,2
amesh,4
amesh,5
amesh,7
esize,0.00001
type,1
mat,3
amesh,10
esize,4*h
type,1
mat,3
amesh,11
finish
/solu
antype,4
solcontrol,on,0
sfl,25,conv,11.447,,20,,
sfl,22,conv,11.447,,20,,
sfl,19,conv,11.447,,20,,
sfl,16,conv,11.447,,20,,
sfl,13,conv,11.447,,20,,
sfl,10,conv,11.447,,20,,
sfl,7,conv,11.447,,20,,
sfl,3,conv,11.447,,20,,
sfl,24,conv,11.447,,20,,
aplot
asel,s,,,11
nsla,s,1
nplot
d,all,temp,320
NSEL,INVE
/replot
ic,all,temp,20
allsel,all
time,20
autots,-1
deltim,0,1,2,1
kbc,1
outres,all,all
solve
asel,s,,,11
nsla,s,1
ddele,all,temp
sfl,4,conv,11.447,,20,,
time,25
nsubst,5
allsel,all
solve