ansys-3d谐波分析-分别使用solid117与solid236,结果不一样
一个金属小球在谐波磁场中受到洛伦兹力代码如下:
/prep7
et,1,117
et,2,117
et,3,117
mp,murx,1,1
mp,murx,2,1
mp,murx,3,1
mp,rsvx,1,1e-8
mp,rsvx,3,1e-7
emunit,mks
cswp,11,1
csys,11
wpcsys,-1,11
cyl4,0,0,0.01,0,0.008,360,0.004
cm,coil,volu
csys
wpcsys,-1
wpoffs,0,0,0.02
sphere,0.002,,0,360
csys
wpcsys,-1
sphere,0.05,,0,360
allsel
vsbv,3,1,,dele,keep
numcmp,all
vsbv,3,2,,dele,keep
numcmp,all
vsel,s,,,1
vatt,1,,1,11
esize,0.001
vsweep,1
vsel,s,,,2
vatt,2,,2
esize,0.001
mshape,1,3d
vmesh,2
vsel,s,,,3
vatt,3,,3
cm,sample,volu
esize,0.01
mshape,1,3d
vmesh,3
alls
nsel,s,ext ! flux parallel exterior
csys
d,all,az
vsel,s,mat,,1
alls,belo,volu
bfe,all,js,,,1e6,,
alls
/solu
antype,harmonic
harf,2500000
solve
fini
/post1
cmsel,s,'sample'
ETABLE,FMAGX,FMAG,X
ETABLE,FMAGY,FMAG,y
ETABLE,FMAGz,FMAG,z
SSUM
*GET,FX,SSUM,,ITEM,FMAGX
*GET,FY,SSUM,,ITEM,FMAGY
*GET,Fz,SSUM,,ITEM,FMAGz
使用solid117时的结果:
SUM ALL THE ACTIVE ENTRIES IN THE ELEMENT TABLE
TABLE LABEL TOTAL
FMAGX -0.510094E-21
FMAGY -0.113975E-21
FMAGZ -0.356364E-21
使用solid236时的结果:
TABLE LABEL TOTAL
FMAGX -0.316274E-05
FMAGY 0.113224E-04
FMAGZ 0.279406E-05
可以看出solid117的结果似乎是错误的,可是这是为什么呢? “....Solid117单元最好使用六面体剖分。根据笔者经验,剖分的形状非常严重地影响计算精度。如,对截面为圆形的电力电缆,理论上不可能用六面体剖分单元完成,并且经过试计算,完全和Solid97相同剖分的条件下,涡流方向在局部定性错误。所以,在这种情况下并非117单元最好。”
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