梁壳体连接情况的讨论
1 按“杆梁壳体”的顺序,只要后一种单元的自由度完全包容了前一种单元的自由度,则有公用结点即可,不需要约束方程。例如:
杆与梁、壳、体有公用结点即可,不需要写约束方程;
梁与壳有公用结点即可,不需要写约束方程;
梁与体则要同位置的不同结点,需要耦合自由度和约束方程;
壳与体则要同位置的不同结点,需要耦合自由度和约束方程;
2 壳梁自由度数目相同,自由度也相同,尽管壳的rotz是虚的自由度,也不妨碍二者之间的关系,这有点类同于梁与杆的关系。
3 尽管可以采用耦合自由度和约束方程,但建议尽量不同时采用多种单元于一个结构中,除非你对结果的正确性有十足的把握。
4 当然,采用约束方程可能存在应力集中点,不必在意此点的应力。
5 我自认为是正确的,希望各位大侠批评指正。
6 为说明上述说法的正确性,这里提供有5个小例子。例1是全“壳单元”,例2是“梁壳单元”;例3是全“体单元”,例4是“体梁单元”,例5是“体壳单元”。
7 运行于ansys6.1下,三月雨提供。
!**********************************************
!梁壳的耦合问题小算例
!采用壳单元时exam1
/prep7
et,1,shell63
mp,ex,1,3e5
mp,prxy,1,0.0
r,1,1.0
wprota,0,90
blc4,,,120,10
aesize,all,2
mshape,0,2d
mshkey,1
amesh,all
/view,1,1,1,1
/ang,1
eplot
nsel,s,loc,x,0
d,all,all
nsel,s,loc,x,120
*get,nhzs,node,,count
f,all,fy,-3/nhzs
allsel,all
/solu
solve
!**********************************************
!梁壳的耦合问题小算例
!采用梁壳单元时exam2
/prep7
et,1,shell63
et,2,beam4
mp,ex,1,3e5
mp,prxy,1,0.0
r,1,1.0
r,2,10.0,10/12.0,1000/12.0,10.0,1.0
wprota,0,90
blc4,,,60,10
wpoff,,5
wprota,,90
asbw,all
k,100,120,0,5
ksel,s,loc,x,60,120
ksel,r,loc,z,5
*get,kp1,kp,,num,min
kp2=kpnext(kp1)
l,kp1,kp2
ksel,all
wpcsys,-1
lsel,s,loc,x,60,120
latt,1,2,2
lesize,all,,,10
lmesh,all
asel,all
aatt,1,1,1
aesize,all,2
mshape,0,2d
mshkey,1
amesh,all
allsel,all
/view,1,1,1,1
/ang,1
eplot
finish
!------------------------
/solu
nsel,s,loc,x,0
d,all,all
nsel,s,loc,x,120
f,all,fy,-3.0
allsel,all
solve
/post1
etable,zl1,smisc,1
etable,zl2,smisc,7
etable,jly1,smisc,2
etable,jly2,smisc,8
etable,jlz1,smisc,3
etable,jlz2,smisc,9
etable,mx1,smisc,4
etable,mx2,smisc,10
etable,my1,smisc,5
etable,my2,smisc,11
etable,mz1,smisc,6
etable,mz2,smisc,12
!**********************************************
!梁壳体的耦合问题小算例
!全部采用体单元时exam3
/prep7
et,1,solid95
mp,ex,1,3e5
mp,prxy,1,0.0
r,1
blc4,,,20,7,10
blc4,20,3,100,1,10
vglue,all
wpoff,0,3
wprota,0,90
vsbw,all
wpoff,0,0,-1
vsbw,all
wpstyle
/view,1,1,1,1
/ang,1
vplot
esize,1
mshape,0,2d
mshkey,1
vmesh,all
finish
/solu
asel,s,loc,x,0
da,all,all
allsel,all
nsel,s,loc,x,119.6,120
nsel,r,loc,y,4
*get,nhzs,node,,count
f,all,fy,-3/nhzs
allsel,all
solve
!**********************************************
!梁壳体的耦合问题小算例
!采用体单元和梁单元时exam4
/prep7
et,1,solid95
et,2,beam4
mp,ex,1,3e5
mp,prxy,1,0.0
r,1
r,2,10.0,10/12.0,1000/12.0,10.0,1.0
blc4,,,20,7,10
wpoff,0,3.5
wprota,0,90
vsbw,all
wpoff,0,5
wprota,0,90
vsbw,all
wpcsys,-1
k,100,20,3.5,5
k,101,120,3.5,5
l,100,101
lsel,s,loc,x,21,130
latt,1,2,2
lesize,all,,,10
lmesh,all
vsel,all
vatt,1,1,1
esize,1
mshape,0,2d
mshkey,1
vmesh,all
allsel,all
/view,1,1,1,1
/ang,1
eplot
finish
!------------------------
/solu
asel,s,loc,x,0
da,all,all
allsel,all
fk,101,fy,-3.0
cp,1,ux,1,21
cp,2,uy,1,21
cp,3,uz,1,21
ce,1,0,626,ux,1,2328,ux,-1,1,roty,-abs(nz(626)-nz(2328))
ce,2,0,67,ux,1,4283,ux,-1,1,rotz,-abs(ny(67)-ny(4283))
ce,3,0,67,uz,1,4283,uz,-1,1,rotx,-abs(ny(67)-ny(4283))
allsel,all
solve
finish
!------------------------
/post1
etable,zl1,smisc,1
etable,zl2,smisc,7
etable,jly1,smisc,2
etable,jly2,smisc,8
etable,jlz1,smisc,3
etable,jlz2,smisc,9
etable,mx1,smisc,4
etable,mx2,smisc,10
etable,my1,smisc,5
etable,my2,smisc,11
etable,mz1,smisc,6
etable,mz2,smisc,12
!**********************************************
!梁壳体的耦合问题小算例
!采用体壳单元时exam5
/prep7
et,1,solid95
et,2,shell63
mp,ex,1,3e5
mp,prxy,1,0.0
r,1
r,2,1.0
blc4,,,20,7,10
wpoff,0,3.5
wprota,0,90
vsbw,all
wpoff,20
blc4,,,100,10
wpcsys,-1
vsel,all
vatt,1,1,1
esize,2
mshape,0,2d
mshkey,1
vmesh,all
asel,s,loc,x,21,120
aatt,1,2,2
aesize,all,2
mshape,0,2d
mshkey,1
amesh,all
allsel,all
/view,1,1,1,1
/ang,1
eplot
asel,s,loc,x,0
da,all,all
allsel,all
cpintf,ux
cpintf,uy
cpintf,uz
ce,1,0,1226,rotz,-abs(ny(197)-ny(742)),197,ux,1,742,ux,-1
ce,2,0,1276,rotz,-abs(ny(201)-ny(971)),201,ux,1,971,ux,-1
ce,3,0,1277,rotz,-abs(ny(205)-ny(969)),205,ux,1,969,ux,-1
ce,4,0,1278,rotz,-abs(ny(209)-ny(967)),209,ux,1,967,ux,-1
ce,5,0,1279,rotz,-abs(ny(213)-ny(965)),213,ux,1,965,ux,-1
ce,6,0,1170,rotz,-abs(ny(194)-ny(701)),194,ux,1,701,ux,-1
ce,7,0,1226,rotx,-abs(ny(197)-ny(742)),197,uz,1,742,uz,-1
ce,8,0,1276,rotx,-abs(ny(201)-ny(971)),201,uz,1,971,uz,-1
ce,9,0,1277,rotx,-abs(ny(205)-ny(969)),205,uz,1,969,uz,-1
ce,10,0,1278,rotx,-abs(ny(209)-ny(967)),209,uz,1,967,uz,-1
ce,11,0,1279,rotx,-abs(ny(213)-ny(965)),213,uz,1,965,uz,-1
ce,12,0,1170,rotx,-abs(ny(194)-ny(701)),194,uz,1,701,uz,-1
nsel,s,loc,x,120
*get,nhzs,node,,count
f,all,fy,-3/nhzs
allsel,all
/solu
solve
**********有一定见解88888**************
三月雨 |