trychiyujian 发表于 2009-5-26 16:08

耦合模态分析

大家好，我在做流固耦合（储罐）模态分析时遇到了这样几个错误，恳求大侠帮忙
1、Both solid model and finite element model boundary conditions have been applied to this model.As solid loads are transferred to the nodes orelements, they can overwrite directly applied loads.
2、Large negative pivot value( -120952.854 ) at node 2584 UZ       May be because a rigid body motion is not represented by master   degrees of freedom.
3、 Reduced mass matrix is not positive definite at node 3852 UZ       redistribute masters to high mass areas.      
我的命令流如下：
fini
/clear
/units,si                                 
*set,guanhou,0.032 !壁厚按最底层计算
*set,r,40 !罐的内径
*set,ye_h,20.2 !充液高度
*set,guan_h,21.8!罐高
*set,fen1,16    !线的划分
*set,fen2,5      !线的划分
*set,fen3,1      !线的划分
/filn,zizhenfenxi,1
/titl,ouhe
/prep7
et,1,shell63
mp,ex,1,2e11
mp,nuxy,1,0.3
mp,dens,1,7.85e3
r,1,guanhou,guanhou,guanhou,guanhou
et,2,80
mp,ex,2,3e10
mp,dens,2,1000
mp,visc,2,0.0024

k,1,
k,2,,,ye_h
k,3,,,guan_h
k,4,r
k,5,r,,ye_h
l,1,4
l,4,5
l,2,3
arota,1,2,,,,,1,2
adrag,11,13,15,17,,,3
type,1
real,1
mat,1
lesize,10,,,fen1
lesize,12,,,fen1
lesize,14,,,fen1
lesize,16,,,fen1
lesize,5,,,fen2
lesize,7,,,fen2
lesize,9,,,fen2
lesize,1,,,fen1
lesize,6,,,fen1
lesize,8,,,fen1
lesize,19,,,fen3
lesize,20,,,fen3
lesize,22,,,fen3
mshkey,1
mshape,0,2D
amesh,all
cyl4,,,40,,,,ye_h
wpro,,90
vsbw,1
wpro,,,90
vsbw,2
vsbw,3
wpstyl,defa
type,2
mat,2
lesi,30,,,fen1
lesi,31,,,fen1
lesi,32,,,fen1
lesi,46,,,fen2
lesi,35,,,fen2
lesi,34,,,fen2
lesi,40,,,fen1
lesi,41,,,fen1
lesi,45,,,fen1
mshkey,1
mshape,0,3D
vmesh,all
fini
/solu
antype,2
modopt,reduc,10
mxpand,10,,,1

csys,1
alls,below,volu
nsel,r,loc,z,ye_h
m,all,uz
alls,below,volu
nsel,r,loc,x,r
m,all,ux
alls
asel,s,area,,1
asel,a,area,,3
asel,a,area,,5
asel,a,area,,7
allsel,below,area            
nsla,s,1
nsel,r,loc,x,0,39
d,all,all

alls
asel,r,area,,8
asel,a,area,,31
asel,a,area,,22
asel,a,area,,27
sfa,all,,fsin,1
alls
asel,r,area,,2
asel,a,area,,4
asel,a,area,,6
asel,a,area,,8
sfa,all,,fsin,1
acel,,,9.8
alls
solv
save
fini

trychiyujian 发表于 2009-5-26 16:08

我先顶一下，大侠们帮忙啊

trychiyujian 发表于 2009-5-26 16:17

主自由度的选择，我是按照文献上做得，选择z向，和径向

16443 发表于 2009-5-26 16:25

回复 楼主 trychiyujian 的帖子

1.这个提示无所谓，想避免这个提示就选择solid model加载或者 finite element model加载中的一种。
2.找到2584点，然后检查这点的约束条件。
3。是由2引起的。

trychiyujian 发表于 2009-5-28 21:34

回复 地板 16443 的帖子

谢谢，第一个明白了，第二个，我还是想不出来。请问壳体和流体之间的耦合是怎么实现的啊？我总觉我这各命令流有些问题啊，请大侠指点一二啊
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