三维电磁力计算求助

254607212

我做的是一个三维电磁铁的电磁力计算，我的程序如下：
/prep7
et,1,117
mp,murx,1,1
mp,murx,2,1000
mp,murx,3,1
mp,murx,4,2000
block,-50,50,0,80,-15,15
block,-30,30,20,100,-100,100
/pnum,volume,1
vsbv,1,2
block,-50,50,100,120,-15,15
block,-25,25,25,80,-15,15
block,-50,50,0,120,-15,15
vovlap,all

numcmp,volume
aplot
vsel,s,volume,,1
vatt,4,1,1
vsel,s,volume,,2
vatt,3,1,1
vsel,s,volume,,3
vatt,2,1,1
allsel,all
smrtsize,2
mshap,1,3d
vmesh,all
vsel,s,,,2
eslv,s
bfe,all,js,1,,,250000
/pnum,mat,1
allsel,all
aplot
esel,s,mat,,4
cm,arm,elem
fmagbc,'arm'

/solu
asel,s,loc,x,50
asel,a,loc,x,-50
asel,a,loc,y,0
asel,a,loc,y,120
asel,a,loc,z,-15
asel,a,loc,z,15
da,all,az,0
allsel,all
solve
finish
/post1
fmagsum,'arm'

如果改变电流，计算所得的电磁力仍然不改变，求助高手帮我看看我程序哪个地方不对