中华钢结构论坛 China Structure Forum

标题: 求助：悬索模态分析中出现的问题！ [打印本页]

作者: Leanfee 时间: 2005-4-20 17:40 标题: 求助：悬索模态分析中出现的问题！

我正在做一水平悬索的模态分析。由于我做的悬索上有集中质量点，不加集中质量点时，运行结果正确，可加了集中质量，就出了问题，出现如下错误：
DOF (e.g. Displacement) limit exceeded at time 1
  (load step 1 substep 1 equilibrium iteration 1)
  Max.absolute value= 4.6048E+16 (limit= 1000000) at UY of node 7 .
   May be due to an unrestrained or unstable model.

LSSOLVE looping is stopped because of a solution error.

我是先建link8单元的索模型，再用mass21单元建集中质量点，两者间我用过耦合，刚化，结果都出现如上错误，请高手们指点一下，不胜感激！

作者: Leanfee 时间: 2005-4-20 17:46 标题: 回复：求助：悬索模态分析中出现的问题！

模型中，悬索一段全约束，一段受水平拉力，索中间有集中质量，在模态分析前先进行有预应力的静力分析，此时出现上述错误，请高手们指点一下！

命令流有点乱，我做过很多次了，不过还是附上。
/BATCH
/COM,ANSYS RELEASE  6.1 UP20020321    08:46:37 04/20/2005
/input,menust,tmp,'',,,,,,,,,,,,,,,,1
/GRA,POWER
/GST,ON
/PLO,INFO,3
/GRO,CURL,ON
/REPLOT,RESIZE
/PREP7
!*
ET,1,LINK8
!*
ET,2,MASS21
!*
!*
R,1,1.2e-4, ,
!*
FINISH
/POST26
SAVE
FINISH
! /EXIT,NOSAV
/BATCH
/COM,ANSYS RELEASE  6.1 UP20020321    09:57:58 04/20/2005
/input,menust,tmp,'',,,,,,,,,,,,,,,,1
/GRA,POWER
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RESUME,file,db,E:\linfei\ansysmulu\jiechuxian\,0,0
/COM,ANSYS RELEASE  6.1 UP20020321    09:58:09 04/20/2005
/PREP7
!*
!*
!*
R,2, ,-0.21, , , , ,
!*
!*
!*
R,3, ,-1.975, , , , ,
!*
!*
!*
!*
!*
!*
MPTEMP,,,,,,,,
MPTEMP,1,0
MPDATA,EX,1,,1.3e11
MPDATA,PRXY,1,,0.3
MPTEMP,,,,,,,,
MPTEMP,1,0
MPDATA,DENS,1,,8942
MPTEMP,,,,,,,,
MPTEMP,1,0
MPDATA,EX,2,,1e11
MPDATA,PRXY,2,,0.35
!*
SAVE,1,db,E:\linfei\ansysmulu\jiechuxian\
K,1,0,0,0,
K,2,0,0,65,
/USER, 1
/VIEW, 1,  0.157047336168E-01,  0.209422763466E-01,  0.999657332491
/ANG,  1,  0.314220925523E-02
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LSTR,    1,    2
FLST,5,1,4,ORDE,1
FITEM,5,1
CM,_Y,LINE
LSEL, , , ,P51X
CM,_Y1,LINE
CMSEL,,_Y
!*
LESIZE,_Y1, , ,80, , , , ,1
!*
LMESH,    1
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/ZOOM,1,RECT,0.237164,0.256579,0.596464,-0.110526
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/ZOOM,1,RECT,0.643845,0.655263,0.916281,0.450000
/ZOOM,  1,  0.0000 ,  0.0000 ,  32.500 ,  1.2000
/ZOOM,1,RECT,0.343770,0.607895,0.829417,0.082895
/ZOOM,1,RECT,-0.019479,0.694737,0.920229,-0.102632
/ZOOM,  1, 0.30437 , 0.41465 ,  32.500 , 0.31500
/ZOOM,1,RECT,-0.291916,-0.272368,0.173990,-0.639474
/ZOOM,  1, 0.30437 , 0.41465 ,  32.500 , 0.31500
/ZOOM,  1,  0.0000 ,  0.0000 ,  32.500 ,  1.2000
/ZOOM,1,RECT,0.106868,0.347368,0.568826,-0.240789
/ZOOM,1,RECT,0.331925,0.327632,0.789934,-0.051316
/ZOOM,  1, 0.58207E-02, 0.63963E-01,  32.500 , 0.35289
/ZOOM,1,RECT,-0.043169,-0.213158,0.399047,-0.481579
/ZOOM,  1, 0.58207E-02, 0.63963E-01,  32.500 , 0.35289
/ZOOM,1,RECT,-0.366934,-0.702632,0.008159,-0.978947
/ZOOM,  1, 0.58207E-02, 0.63963E-01,  32.500 , 0.35289
/ZOOM,  1,  0.0000 ,  0.0000 ,  32.500 ,  1.2000
/ZOOM,1,RECT,-0.106343,-0.071053,0.501704,-0.714474
/ZOOM,1,RECT,-0.287967,0.355263,0.181887,0.047368
/ZOOM,  1,-0.16243 ,-0.47146 ,  32.500 , 0.38605
/ZOOM,1,RECT,-0.528817,-0.090789,-0.051066,-0.603947
FLST,3,8,1,ORDE,8
FITEM,3,7
FITEM,3,17
FITEM,3,27
FITEM,3,37
FITEM,3,47
FITEM,3,57
FITEM,3,67
FITEM,3,77
KNODE,0,P51X
/ZOOM,  1,-0.16243 ,-0.47146 ,  32.500 , 0.38605
/ZOOM,  1,  0.0000 ,  0.0000 ,  32.500 ,  1.2000
/PNUM,KP,1
/PNUM,LINE,0
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/PNUM,NODE,1
/PNUM,TABN,0
/PNUM,SVAL,0
/NUMBER,0
!*
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/REPLOT
!*
KPLOT
FLST,3,10,3,ORDE,2
FITEM,3,1
FITEM,3,-10
NKPT,0,P51X
NPLOT
/ZOOM,1,RECT,0.604361,0.659210,0.900488,0.501316
/ZOOM,1,RECT,0.245061,0.055263,0.604361,-0.300000
/ZOOM,  1, 0.50341 , 0.69661 ,  32.500 , 0.13329
/PNUM,KP,0
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/PNUM,VOLU,0
/PNUM,NODE,1
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/PNUM,SVAL,0
/NUMBER,0
!*
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!*
NPLOT
/ZOOM,  1,  0.0000 ,  0.0000 ,  32.500 ,  1.2000
/ZOOM,1,RECT,0.071333,0.240789,0.600413,-0.185526
/ZOOM,1,RECT,0.932075,0.971053,1.251891,0.347368
/ZOOM,  1, 0.34499E-02, 0.33166E-01,  32.500 , 0.25579
/ZOOM,1,RECT,0.458272,0.378947,0.853107,-0.023684
/ZOOM,  1, 0.34499E-02, 0.33166E-01,  32.500 , 0.25579
/ZOOM,1,RECT,0.932075,0.971053,1.228201,0.726316
/ZOOM,  1, 0.34499E-02, 0.33166E-01,  32.500 , 0.25579
/ZOOM,  1,  0.0000 ,  0.0000 ,  32.500 ,  1.2000
SAVE,2,db,E:\linfei\ansysmulu\jiechuxian\
TYPE, 2
MAT,    2
REAL,    2
ESYS,    0
SECNUM,
TSHAP,LINE
!*
KPLOT
FLST,2,8,1
FITEM,2,84
FITEM,2,85
FITEM,2,86
FITEM,2,87
FITEM,2,88
FITEM,2,89
FITEM,2,90
FITEM,2,91
E,P51X
EPLOT
/PNUM,KP,0
/PNUM,LINE,0
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/PNUM,VOLU,0
/PNUM,NODE,0
/PNUM,TABN,0
/PNUM,SVAL,0
/NUMBER,0
!*
/PNUM,ELEM,0
/REPLOT
!*
EPLOT
/PNUM,KP,0
/PNUM,LINE,0
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/PNUM,SVAL,0
/NUMBER,0
!*
/PNUM,ELEM,0
/REPLOT
!*
/ZOOM,1,RECT,0.264802,0.576316,0.841262,0.150000
/ZOOM,  1,  0.0000 ,  0.0000 ,  32.500 ,  1.2000
/ZOOM,1,RECT,0.584619,0.659210,0.971558,0.225000
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/ZOOM,  1,  0.0000 ,  0.0000 ,  32.500 ,  1.2000
/ZOOM,1,RECT,-0.086601,0.418421,0.714915,-0.047368
/ZOOM,1,RECT,0.553032,0.359211,1.275581,-0.126316
E,    86
/ZOOM,  1,-0.22602E-01, 0.22267 ,  32.500 , 0.36077
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E,    87
/ZOOM,  1,-0.22602E-01, 0.22267 ,  32.500 , 0.36077
/ZOOM,1,RECT,0.130558,-0.682895,0.399047,-0.939474
E,    88
/ZOOM,  1,-0.22602E-01, 0.22267 ,  32.500 , 0.36077
/ZOOM,  1,  0.0000 ,  0.0000 ,  32.500 ,  1.2000
/ZOOM,1,RECT,-0.161620,0.146053,0.347718,-0.438158
E,    89
E,    90
/ZOOM,  1,  0.0000 ,  0.0000 ,  32.500 ,  1.2000
/ZOOM,1,RECT,-0.201103,-0.110526,0.221371,-0.611842
E,    91
EPLOT
/ZOOM,  1,  0.0000 ,  0.0000 ,  32.500 ,  1.2000
/PNUM,KP,0
/PNUM,LINE,0
/PNUM,AREA,0
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/PNUM,NODE,0
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/NUMBER,0
!*
/PNUM,ELEM,0
/REPLOT
!*
TYPE, 2
MAT,    2
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ESYS,    0
SECNUM,
TSHAP,LINE
!*
/ZOOM,1,RECT,0.596464,0.663158,0.987352,0.469737
E,    82
/ZOOM,  1,  0.0000 ,  0.0000 ,  32.500 ,  1.2000
E,    83
EPLOT
SAVE,3,db,E:\linfei\ansysmulu\jiechuxian\
/ZOOM,1,RECT,0.608309,0.663158,0.924178,0.244737
/ZOOM,  1,  0.0000 ,  0.0000 ,  32.500 ,  1.2000
/ZOOM,1,RECT,0.533291,0.568421,0.742553,0.351316
/ZOOM,1,RECT,0.628051,0.355263,0.995248,-0.268421
/ZOOM,  1, 0.36598 , 0.55206 ,  32.500 , 0.13026
/ZOOM,  1,  0.0000 ,  0.0000 ,  32.500 ,  1.2000
/PNUM,KP,0
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/PNUM,AREA,0
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!*
/PNUM,ELEM,0
/REPLOT
!*
/ZOOM,1,RECT,0.616206,0.651316,0.825469,0.398684
/ZOOM,1,RECT,0.493807,0.453947,0.833366,0.240789
/ZOOM,  1, 0.46550 , 0.63027 ,  32.500 , 0.15158
SAVE
/NOPR
CM,_NODECM,NODE
*SET,_z1,    82
NSEL,S, , ,    1
NSEL,A, , ,_Z1
CM,_CERGCM,NODE
CMSEL,S,_NODECM
/GO
!*
/NOPR
CMSEL,S,_CERGCM
/GO
CERIG,82,ALL,ALL, , , ,
/NOPR
CMSEL,S,_NODECM
/GO
!*
/NOPR
CM,_NODECM,NODE
*SET,_z1,    84
NSEL,S, , ,    7
NSEL,A, , ,_Z1
CM,_CERGCM,NODE
CMSEL,S,_NODECM
/GO
!*
/NOPR
CMSEL,S,_CERGCM
/GO
CERIG,84,ALL,ALL, , , ,
/NOPR
CMSEL,S,_NODECM
/GO
!*
/ZOOM,  1,  0.0000 ,  0.0000 ,  32.500 ,  1.2000
/ZOOM,1,RECT,0.470117,0.450000,0.643845,0.177632
/NOPR
CM,_NODECM,NODE
*SET,_z1,    85
NSEL,S, , ,    17
NSEL,A, , ,_Z1
CM,_CERGCM,NODE
CMSEL,S,_NODECM
/GO
!*
/NOPR
CMSEL,S,_CERGCM
/GO
CERIG,85,ALL,ALL, , , ,
/NOPR
CMSEL,S,_NODECM
/GO
!*
/NOPR
CM,_NODECM,NODE
*SET,_z1,    86
NSEL,S, , ,    27
NSEL,A, , ,_Z1
CM,_CERGCM,NODE
CMSEL,S,_NODECM
/GO
!*
/NOPR
CMSEL,S,_CERGCM
/GO
CERIG,86,ALL,ALL, , , ,
/NOPR
CMSEL,S,_NODECM
/GO
!*
/ZOOM,  1,  0.0000 ,  0.0000 ,  32.500 ,  1.2000
/ZOOM,1,RECT,0.008159,0.118421,0.466169,-0.248684
/NOPR
CM,_NODECM,NODE
*SET,_z1,    87
NSEL,S, , ,    37
NSEL,A, , ,_Z1
CM,_CERGCM,NODE
CMSEL,S,_NODECM
/GO
!*
/NOPR
CMSEL,S,_CERGCM
/GO
CERIG,87,ALL,ALL, , , ,
/NOPR
CMSEL,S,_NODECM
/GO
!*
/NOPR
CM,_NODECM,NODE
*SET,_z1,    88
NSEL,S, , ,    47
NSEL,A, , ,_Z1
CM,_CERGCM,NODE
CMSEL,S,_NODECM
/GO
!*
/NOPR
CMSEL,S,_CERGCM
/GO
CERIG,88,ALL,ALL, , , ,
/NOPR
CMSEL,S,_NODECM
/GO
!*
/NOPR
CM,_NODECM,NODE
*SET,_z1,    89
NSEL,S, , ,    57
NSEL,A, , ,_Z1
CM,_CERGCM,NODE
CMSEL,S,_NODECM
/GO
!*
/NOPR
CMSEL,S,_CERGCM
/GO
CERIG,89,ALL,ALL, , , ,
/NOPR
CMSEL,S,_NODECM
/GO
!*
/ZOOM,  1,  0.0000 ,  0.0000 ,  32.500 ,  1.2000
/ZOOM,1,RECT,-0.197155,-0.193421,0.162145,-0.596053
/NOPR
CM,_NODECM,NODE
*SET,_z1,    90
NSEL,S, , ,    67
NSEL,A, , ,_Z1
CM,_CERGCM,NODE
CMSEL,S,_NODECM
/GO
!*
/NOPR
CMSEL,S,_CERGCM
/GO
CERIG,90,ALL,ALL, , , ,
/NOPR
CMSEL,S,_NODECM
/GO
!*
/NOPR
CM,_NODECM,NODE
*SET,_z1,    91
NSEL,S, , ,    77
NSEL,A, , ,_Z1
CM,_CERGCM,NODE
CMSEL,S,_NODECM
/GO
!*
/NOPR
CMSEL,S,_CERGCM
/GO
CERIG,91,ALL,ALL, , , ,
/NOPR
CMSEL,S,_NODECM
/GO
!*
/NOPR
CM,_NODECM,NODE
*SET,_z1,    83
NSEL,S, , ,    2
NSEL,A, , ,_Z1
CM,_CERGCM,NODE
CMSEL,S,_NODECM
/GO
!*
/NOPR
CMSEL,S,_CERGCM
/GO
CERIG,83,ALL,ALL, , , ,
/NOPR
CMSEL,S,_NODECM
/GO
!*
/ZOOM,  1,  0.0000 ,  0.0000 ,  32.500 ,  1.2000
/PNUM,KP,0
/PNUM,LINE,0
/PNUM,AREA,0
/PNUM,VOLU,0
/PNUM,NODE,0
/PNUM,TABN,0
/PNUM,SVAL,0
/NUMBER,0
!*
/PNUM,ELEM,0
/REPLOT
!*
SAVE,mesh,db,E:\linfei\ansysmulu\jiechuxian\
SAVE
FINISH
/SOLU
!*
NLGEOM,0
NROPT,AUTO, ,
LUMPM,0
EQSLV, , ,0,
PRECISION,0
MSAVE,0
PIVCHECK,1
PSTRES,ON
TOFFST,0,
!*
FLST,2,10,3,ORDE,2
FITEM,2,1
FITEM,2,-10
!*
/GO
DK,P51X, ,0, ,0,UX,ROTX, , , , ,
FLST,2,1,3,ORDE,1
FITEM,2,1
!*
/GO
DK,P51X, ,0, ,0,ALL, , , , , ,
FLST,2,8,3,ORDE,2
FITEM,2,3
FITEM,2,-10
!*
/GO
FK,P51X,FY,92.096
ALLSEL,ALL
LSWRITE,1,
FINISH
/BATCH
/COM,ANSYS RELEASE  6.1 UP20020321    15:44:58 04/20/2005
/input,menust,tmp,'',,,,,,,,,,,,,,,,1
/GRA,POWER
/GST,ON
/PLO,INFO,3
/GRO,CURL,ON
/REPLOT,RESIZE
RESUME
/COM,ANSYS RELEASE  6.1 UP20020321    15:45:21 04/20/2005
/SOLU
FLST,2,10,3,ORDE,2
FITEM,2,1
FITEM,2,-10
FKDELE,P51X,ALL
KPLOT
FLST,2,10,3,ORDE,2
FITEM,2,1
FITEM,2,-10
DKDELE,P51X,ALL
EPLOT
FLST,2,9,1,ORDE,2
FITEM,2,83
FITEM,2,-91
!*
/GO
D,P51X, ,0, , , ,UX,ROTX, , , ,
FLST,2,1,1,ORDE,1
FITEM,2,82
!*
/GO
D,P51X, ,0, , , ,ALL, , , , ,
FLST,2,8,1,ORDE,2
FITEM,2,84
FITEM,2,-91
!*
/GO
F,P51X,FY,92.096
LSWRITE,1,
FLST,2,1,1,ORDE,1
FITEM,2,2
!*
/GO
F,P51X,FZ,10000
LSWRITE,2,
ACEL,0,-9.8,0,
LSWRITE,3,
SAVE,load,db,E:\linfei\ansysmulu\jiechuxian\
LSSOLVE,1,3,1,
FINISH
/BATCH
/COM,ANSYS RELEASE  6.1 UP20020321    15:58:12 04/20/2005
/input,menust,tmp,'',,,,,,,,,,,,,,,,1
/GRA,POWER
/GST,ON
/PLO,INFO,3
/GRO,CURL,ON
/REPLOT,RESIZE
RESUME
/COM,ANSYS RELEASE  6.1 UP20020321    15:58:19 04/20/2005
/PNUM,KP,1
/PNUM,LINE,0
/PNUM,AREA,0
/PNUM,VOLU,0
/PNUM,NODE,0
/PNUM,TABN,0
/PNUM,SVAL,0
/NUMBER,0
!*
/PNUM,ELEM,0
/REPLOT
!*
KPLOT
EPLOT
/SOLU
FINISH
/PREP7
CPDELE,,,,ALL
CEDELE,,,,ALL
CEDELE,,,,ANY
CEDELE,,,,ALL
RESUME,3,db,E:\linfei\ansysmulu\jiechuxian\,0,0

作者: bjliu 时间: 2005-5-6 07:22 标题: 回复：求助：悬索模态分析中出现的问题！

  阁下的命令流确实有点乱，我看不了。不过根据你描述的过程，我认为求解出错的原因在于静力分析过程求解不收敛造成的。因为在未加集中质量时，阁下的模型初应力与外载（如自重）自相平衡，结构处于稳定状态，静力求解收敛；而加上集中质量后（计入自重的话），该点出现位移突变超限，造成分析不收敛。要解决该问题，可以这样处理：（1）避免加集中质量的节点位移突变，可以只计入质量，而不将质量产生的重量加在该点（不在该点计入重力），可以在附近区域以加力的方式代替集中质量产生的重力。（2）改变迭代收敛方式，细分荷载步缓慢加载等方式帮助收敛。
  在模态分析中只计入应力刚度即可，不应该会有什么问题。
       mass21可以直接定义在索节点上，不采用耦合，因为耦合中的设置可能会影响模态分析，如BEAM4就有此问题。

作者: Leanfee 时间: 2005-5-10 10:09 标题: 回复：求助：悬索模态分析中出现的问题！

谢谢bjliu兄的帮助！受益匪浅

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