heaventian 发表于 2009-7-2 17:40

网格化分时警告,修改后,出错,请问什么原因!

前面建立模型时没有问题,但是网格化分的时候,
输入
MSHAPE,1,3D
开始出现警告:
structural elements withoutmid nodes uaually
produce much more accurate results in quad or brick shape

我就按照它的指示,将四面体单元单元改为六面体单元,即
MSHAPE,0,3D
MSHKEY,0
然后
VMESH的时候,就出错了:
CANNOT FREE MESH WITH HEXAHEDRAL ELEMENTS

他什么意思啊?刚说,四面体精度不行,改为六面体,又报错。
请问大家该怎么改啊?


命令流:
/PREP7
ET,1,SOLID45
/PNUM,KP,1
/PNUM,LINE,1
/NUMBER,0
K,1,-180,0,0
K,2,-180,35,0
K,3,-135,35,0
L,1,2
L,2,3
LPLOT
CSYS,1
K,4,135,135,0
K,5,95,180,0
K,6,95,135,0
L,3,4
L,5,6
LFILLT,2,3,30
LPLOT
WPROTA,45
CSYS,4
ALLSEL
LSYMM,X,ALL
WPROTA,-45
WPOFFS,600
CSWPLA,11,1
K,16,75,0,0
K,17,75,135,0
K,18,40,0,0
K,19,40,180,0
L,16,17
L,18,19
CSYS,0
LSEL,S,,,4,6,2
LSEL,A,,,7,9,2
LSYMM,X,ALL
K,27,250,55,0
K,28,520,45,0
BSPLIN,17,28,27,24
ALLSEL
LPLOT
LFILLT,15,17,40
LFILLT,11,17,150
ALLSEL
LPLOT
LSYMM,Y,ALL
ALLSEL
NUMMRG,KP
LPLOT
LSEL,S,,,12,31,19
LPLOT
AL,ALL
LSEL,S,,,4,9,5
LSEL,A,,,13,16,3
LSEL,A,,,23,28,5
LSEL,A,,,32,35,3
LPLOT
AL,ALL
ALLSEL
LSEL,U,,,12,31,19
LSEL,U,,,4,9,5
LSEL,U,,,13,16,3
LSEL,U,,,23,28,5
LSEL,U,,,32,35,3
LPLOT
AL,ALL
APLOT
/PNUM,AREA,1
/PNUM,LINE,0
/PNUM,KP,0
/REPLOT
ASBA,3,1
ASBA,4,2
NUMCMP,ALL
APLOT
VOFFST,1,50
/VIEW,1,1,2,3
VPLOT
ALLSEL
SMRT,10

MSHAPE,1,3D
MSHKEY,0
VMESH,1
!SAVE
FINISH

jxxansys 发表于 2009-7-2 23:17

自由网格不能使用六面体单元,如果提示四面体精度不足的话,可以使用高阶单元

heaventian 发表于 2009-7-3 14:48

谢谢,试了一下,自由网格果然不能使用六面体单元
finish
/clear
/prep7
et,1,solid45
block,0,1,0,1,0,1
/view,1,1,2,3
/replot
smrtsize,7
mshape,0,3d
mshkey,0
vmesh,1
如果将mshkey,0改为mshkey,1就可以了:
finish
/clear
/prep7
et,1,solid45
block,0,1,0,1,0,1
/view,1,1,2,3
/replot
smrtsize,7
mshape,0,3d
mshkey,1
vmesh,1


但是本文不止这么一个问题,如果采用六面体,且用mapped划分网格的话,仍然会报错:
volume 1 has invalid topology for mapped brick meshing
网上搜了一下,原因是因为几何模型的体块不规则。
看来只能够用四面体单元了,现在决定采用solid92
请问mapped划分六面体都在什么条件下能够划分?

16443 发表于 2009-7-3 15:21

边界满足映射条件
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