w1h2y3 发表于 2009-6-17 14:19

请教不规则空心壳体变形问题

一个不规则空心球壳,在一定内部压强下发生变形(由于对称性只分析了1/4球壳)。在
ANSYS中选择Shell93单元进行大变形分析,网格划分采用三角形映射方式,但是每次求
解的时候都出现错误,提示部分单元高度扭曲,细化网格或者增加求解步数都不行,在
此请教大家。命令流如下,谢谢大家支招啊。

而且发现当壳体是空心球形壳体时,都可以成功分析以上变形。难道ansys不能分析这种
形状的球壳吗?

经常报一下错误,也细化了网络,而且也换了一些单元类型,比如shell141,shell63等
都没用。

One or more elements have become highly distorted.Excessive distortion of
elements is usually a symptom indicating the need for corrective action
elsewhere.Try incrementing the load more slowly(increase the number of
substeps or decrease the time step size).Youmay need to improve your
mesh to obtain elements with better aspect ratios.Also consider the
behavior of materials, contact pairs, and/or constraint equations.If this
message appears in the first iteration of first substep, be sure to perform
element shape checking

命令流如下:
/BATCH
/COM,ANSYS RELEASE8.0    UP20030930       14:01:37    06/15/2009
SAVE
/PREP7
!*
ET,1,SHELL93
!*
KEYOPT,1,4,0
KEYOPT,1,5,0
KEYOPT,1,6,0
KEYOPT,1,8,0
!*
SAVE
R,1,20e-9, , , , , ,
!*
SAVE
/BATCH
/COM,ANSYS RELEASE8.0    UP20030930       14:02:33    06/15/2009
RESUME,'success1','db','.'
/COM,ANSYS RELEASE8.0    UP20030930       14:02:33    06/15/2009
/PREP7
!*
MPTEMP,,,,,,,,
MPTEMP,1,0
MPDATA,EX,1,,1950   
MPDATA,PRXY,1,,0.49
SAVE
*SET,r0,3.91e-6
*SET,c0,0.207161
*SET,c1,2.002558
*SET,c2,-1.122762   
SAVE
csys,0
*dim,a,,200
*dim,b,,200
*dim,c,,200
*dim,d,,200
*do,i,1,200
*SET,a(i),r0/199*(i-1)
*SET,b(i),sqrt(1-a(i)*a(i)/(r0*r0))
*SET,c(i),c0+c1*a(i)*a(i)/(r0*r0)+c2*a(i)*a(i)/(r0*r0)*(a(i)*a(i)/(r0*r0))
*SET,d(i),0.5*r0*b(i)*c(i)
*enddo
/prep7
*do,i,1,200
k,i,a(i),d(i),0
*enddo
ksel,s,,,1,200
bsplin,all
LPLOT   
/DIST,1,0.924021086472,1
/REP,FAST   
/DIST,1,1.08222638492,1
/REP,FAST   
SAVE
K,1000,0,0,0,   
SAVE
FLST,2,1,4,ORDE,1   
FITEM,2,1   
FLST,8,2,3
FITEM,8,1   
FITEM,8,1000
AROTAT,P51X, , , , , ,P51X, ,-90, ,
/VIEW,1,1,1,1   
/ANG,1
/REP,FAST   
/DIST,1,1.08222638492,1
/REP,FAST   
/DIST,1,1.08222638492,1
/REP,FAST   
/DIST,1,1.08222638492,1
/REP,FAST   
/USER,1   
/VIEW,1,0.603823704366    ,0.590907160695    ,0.535000618211
/ANG,   1,   2.87936336760
/REPLO
/FOC,   1,0.146625114858E-05,0.520686473630E-06, -0.127011745556E-05
/REPLO
SAVE
FLST,5,2,4,ORDE,2   
FITEM,5,1   
FITEM,5,-2
CM,_Y,LINE
LSEL, , , ,P51X
CM,_Y1,LINE
CMSEL,,_Y   
!*
LESIZE,_Y1, , ,30, , , , ,1
!*
FLST,5,1,4,ORDE,1   
FITEM,5,3   
CM,_Y,LINE
LSEL, , , ,P51X
CM,_Y1,LINE
CMSEL,,_Y   
!*
LESIZE,_Y1, , ,40, , , , ,1
!*
SAVE
MSHAPE,1,2D
MSHKEY,1
!*
CM,_Y,AREA
ASEL, , , ,       1
CM,_Y1,AREA
CHKMSH,'AREA'   
CMSEL,S,_Y
!*
AMESH,_Y1   
!*
CMDELE,_Y   
CMDELE,_Y1
CMDELE,_Y2
!*
FINISH
/SOL
!*
/PSF,PRES,NORM,2,0,1
/PBF,DEFA, ,1   
/PIC,DEFA, ,1   
/PSYMB,CS,0
/PSYMB,NDIR,0   
/PSYMB,ESYS,0   
/PSYMB,LDIV,0   
/PSYMB,LDIR,0   
/PSYMB,ADIR,0   
/PSYMB,ECON,0   
/PSYMB,XNODE,0
/PSYMB,DOT,1
/PSYMB,PCONV,   
/PSYMB,LAYR,0   
/PSYMB,FBCS,0   
!*
/PBC,ALL, ,1
/REP
!*
FLST,2,3,4,ORDE,2   
FITEM,2,1   
FITEM,2,-3
DL,P51X, ,SYMM
FLST,5,2400,2,ORDE,2
FITEM,5,1   
FITEM,5,-2400   
CM,_Y,ELEM
ESEL, , , ,P51X
CM,_Y1,ELEM
CMSEL,S,_Y
CMSEL,ALL   
CMDELE,_Y   
!*
/GO
!*
SFE,_Y1,1,PRES, ,5, , ,
/VIEW,1,0.341079442346    ,0.254293234521    ,0.904986057841
/ANG,   1,-9.70964789045
/REPLO
/VIEW,1,0.367516929604    , -0.587101404359E-01,0.928161853269
/ANG,   1,-9.63015461642
/REPLO
/VIEW,1,0.522803579732    ,0.511854082944    ,0.681675740212
/ANG,   1,-5.94322254689
/REPLO
FLST,5,2400,2,ORDE,2
FITEM,5,1   
FITEM,5,-2400   
CM,_Y,ELEM
ESEL, , , ,P51X
CM,_Y1,ELEM
CMSEL,S,_Y
CMSEL,ALL   
CMDELE,_Y   
!*
/GO
!*
SFE,_Y1,1,PRES, ,-5, , ,
/REPLOT
SAVE
ANTYPE,0
NLGEOM,1
NSUBST,30,50,20
OUTRES,ERASE
OUTRES,ALL,ALL
SAVE
/STATUS,SOLU
SOLVE   
FINISH
/POST1
SET,LAST
PLDISP,1
/DIST,1,1.08222638492,1
/REP,FAST   
/DIST,1,1.08222638492,1
/REP,FAST   
/DIST,1,1.08222638492,1
/REP,FAST   
/DIST,1,1.08222638492,1
/REP,FAST   
/DIST,1,1.08222638492,1
/REP,FAST   
/DIST,1,1.08222638492,1
/REP,FAST   
/DIST,1,1.08222638492,1
/REP,FAST   
/DIST,1,1.08222638492,1
/REP,FAST   
/DIST,1,1.08222638492,1
/REP,FAST   
/DIST,1,1.08222638492,1
/REP,FAST   
FINISH
/SOL
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