ansys模态分析，beam3和beam188，solid45

ME! · 发表于 2013-6-27 17:04

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两种单元的结果为什么相差那么大，我添加了附加质量，beam188质量单元设置为ux uy uz ixx iyy izz ,beam3单元设置为ux uy uz ,当不加附加质量的简支梁用平面钢架单元matlab计算结果一致，为什么添加了附加质量，结果相差那么大（数据上有点小小误差）平面钢架元刚度矩阵
c=E*I/(L^3);
y=[E*A/L 0          0          -E*A/L    0       0;...
   0 12*c       6*L*c    0 -12* c    6*L*c;...
   0 6*L*c 4*L^2*c 0 -6*L*c 2*L^2*c;...
-E*A/L 0          0          E*A/L    0       0;...
   0  -12*c    -6*L*c    0    12*c    -6*L*c;...
   0 6*L*c 2*L^2*c 0 -6*L*c 4*L^2*c];
质量单元
  m = (rho*A*L/420)*[140    0    0 70    0    0;
                  0 156 22*L 0    54 -13*L;
                  0 22*L  4*L^2 0 13*L  -3*L^2;
                  70    0    0  140    0    0 ;
                  0    54 13*L 0 156 -22*L;
                  0  -13*L -3*L^2 0  -22*L  4*L^2 ] ;

beam188单元模型

FINISH
/CLEAR
/prep7
MP,EX,1,2.06E11 !ex: 弹性模量
MP,DENS,1,7850 !密度
MP,GXY,1,1E12 !gxy为剪切模量
MP,PRXY,1,0.3 !泊松比
ET,1,beam188,,,2 !=0时 (默认), 每节点有6个自由度。分别是沿x,y,z的位移及绕其的转动。
*DIM,DIAM,ARRAY,16 !定义直径数组
DIAM(1) = 0.015
DIAM(2) = 0.016
DIAM(3) = 0.017
DIAM(4) = 0.017
DIAM(5) = 0.0205
DIAM(6) = 0.029
DIAM(7) = 0.0217
DIAM(8) = 0.030
DIAM(9) = 0.020
DIAM(10) = 0.017
DIAM(11) = 0.017
DIAM(12) = 0.0205
DIAM(13) = 0.017
DIAM(14) = 0.017
DIAM(15) = 0.016
DIAM(16) = 0.0125
*DO,I,1,16
SECTYPE,I,BEAM,CTUBE !截面类型ID: 截面号TYPE: BEAM:定义此截面用于梁 CSOLID:圆形实心截面CTUBE: 圆管
SECDATA,0.004,DIAM(I)/2,40 !Ri, Ro, N
*ENDDO
ET,3,COMBIN14 ! ELEMENT TYPE #3 : BEARINGS
KEYOPT,3,2,2 ! Y DIRECTION
ET,4,COMBIN14
KEYOPT,4,2,3 ! Z DIRECTION
R,30,164E+6 ! BEARINGS
ET,32,mass21
R,32,0.0248,0.0248,0.0248,0.0324,0.0162,0.0162
ET,33,mass21
R,33,0.0577,0.0577,0.0577,0.1188,0.05941,0.05941
ET,34,mass21
R,34,0.0577,0.0577,0.0577,0.1188,0.05941,,0.05941
ET,38,mass21
R,38,0.134,0.134,0.134,0.7199,0.3599,,0.3599
ET,313,mass21
R,313,0.0577,0.0577,0.0577,0.1188,0.05942,,0.05942
ET,314,mass21
R,314,0.0577,0.0577,0.0577,0.1188,0.05942,0.05942
ET,315,mass21
R,315,0.02051,0.02051,0.02051,0.0280,0.014,0.014
ET,316,mass21
R,316,0.06647,0.06647,0.06647,0.01235,0.06176,0.06176
N,1,0
N,2,0.0165
N,3,0.03
N,4,0.034
N,5,0.044
N,6,0.049
N,7,0.0555
N,8,0.0585
N,9,0.065
N,10,0.1122
N,11,0.1172
N,12,0.1377
N,13,0.1427
N,14,0.1527
N,15,0.1575
N,16,0.164
N,17,0.187
BRG =0 ! BEARING "LENGTH" FOR VISUALISATION
N,18,0.034,BRG
N,19,0.044,BRG
N,20,0.1427,BRG
N,21,0.1527,BRG
N,22,0.034,,BRG
N,23,0.044,,BRG
N,24,0.1427,,BRG
N,25,0.1527,,BRG
TYPE,1
MAT,1
*DO,I,1,16
E,I,I+1
SECNUM,I !指定梁的截面号
*ENDDO
n,400001,0.022,0,0
n,400002,0.085,0,0
n,400003,0.1574,0,0
n,400004,0.1755,0,0
TYPE,32 !建立质量单元
real,32
e,400001
TYPE,33
real,33
e,18
TYPE,34
real,34
e,19
TYPE,38
real,38
e,400002
TYPE,313
real,313
e,20
TYPE,314
real,314
e,21
TYPE,315
real,315
e,400003
TYPE,316
real,316
e,400004
TYPE,3 ! y向弹簧单元
REAL,30
E,18,4
E,19,5
E,21,14
E,20,13
TYPE,4 ! z向弹簧单元
REAL,30
E,22,4
E,23,5
E,24,13
E,25,14
FINI
eplot
finish
/SOLU
D,18,ALL
D,19,ALL
D,20,ALL
D,21,ALL
D,22,ALL
D,23,ALL
D,24,ALL
D,25,ALL
D,ALL,UX ! 不考虑扭转和轴向移动
D,ALL,ROTX
/SOLU
ANTYPE,MODAL
CORIOLIS,ON,,,ON
MODOPT,QRDAMP,30,,,ON
MXPAND,30
SOLVE

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beam3模型

finish
/clear
/prep7
RO = 7850
PEX = 2.06E11
MP,EX,1,PEX !ex: 弹性模量
MP,DENS,1,RO !密度
MP,GXY, 1,EX/2.6
MP,PRXY,1,0.3
ET,1,beam3,,,
ET,32,mass21 !mass ux uy uz
keyopt,32,3,4
R,32,0.0248,0.0248,0.0248
ET,33,mass21
keyopt,33,3,4
R,33,0.0577,0.0577,0.0577
ET,34,mass21
keyopt,34,3,4
R,34,0.0577,0.0577,0.0577,
ET,38,mass21
keyopt,38,3,4
R,38,0.134,0.134,0.134
ET,313,mass21
keyopt,313,3,4
R,313,0.0577,0.0577,0.0577
ET,314,mass21
keyopt,314,3,4
R,314,0.0577,0.0577,0.0577
ET,315,mass21
keyopt,315,3,4
R,315,0.02051,0.02051,0.02051
ET,316,mass21
keyopt,316,3,4
R,316,0.06647,0.06647,0.06647
ET,2,COMBIN14 ! ELEMENT TYPE #3 : BEARINGS
keyopt,2,2,2
R,2,164e6
ET,3,COMBIN14 ! ELEMENT TYPE #3 : BEARINGS
keyopt,3,2,3
R,3,164e6
*DIM,DIAM,ARRAY,16 !定义直径数组
DIAM(1) = 15E-3
DIAM(2) = 16E-3
DIAM(3) = 17E-3
DIAM(4) = 17E-3
DIAM(5) = 20.5E-3
DIAM(6) = 29E-3
DIAM(7) = 21.7E-3
DIAM(8) = 21E-3
DIAM(9) = 20E-3
DIAM(10) = 17E-3
DIAM(11) = 17E-3
DIAM(12) = 20.5E-3
DIAM(13) = 17E-3
DIAM(14) = 17E-3
DIAM(15) = 16E-3
DIAM(16) = 12.5E-3
*DIM,AERA,ARRAY,16 !定义横截面面积数组
AERA(1) = 0.000126449104
AERA(2) = 0.000150796447
AERA(3) = 0.000176714587
AERA(4) = 0.000176714587
AERA(5) = 0.0002797980
AERA(6) = 0.000610254372
AERA(7) = 0.0003195707
AERA (8) = 0.0002960951
AERA(9) = 0.0002638938
AERA(10) = 0.00017671459
AERA(11) = 0.00017671459
AERA(12) = 0.00027979808
AERA(13) = 0.00017671459
AERA(14) = 0.00017671459
AERA (15) = 0.00015079645
AERA(16) = 0.00007252981
*DIM,IZZ,ARRAY,16 !定义截面惯性矩数组
IZZ(1) = 0.022839869465450E-7
IZZ(2) = 0.030159289474462E-7
IZZ(3) = 0.038987655704901E-7
IZZ(4) = 0.038987655704901E-7
IZZ(5) = 0.084682642404833E-7
IZZ(6) = 0.084682642404833E-7
IZZ(7) = 0.106834468521627E-7
IZZ(8) = 0.093455018336514E-7
IZZ(9) = 0.076529197041447E-7
IZZ(10) = 0.038987655704901E-7
IZZ(11) = 0.038987655704901E-7
IZZ(12) = 0.084682642404833E-7
IZZ(13) = 0.038987655704901E-7
IZZ(14) =0.038987655704901E-7
IZZ(15) = 0.030159289474462E-7
IZZ(16) = 0.009973605607059E-7
*DO,I,1,16
R,1,AERA(I),IZZ(I),DIAM(I)
*ENDDO
N,1,0
N,2,0.0164
N,3,0.029
N,4,0.039
N,5,0.049
N,6,0.0555
N,7,0.0585
N,8,0.065
N,26,0.09
N,9,0.1122
N,10,0.1172
N,11,0.1222
N,12,0.1272
N,13,0.1377
N,14,0.1477
N,15,0.1577
N,16,0.164
N,17,0.187
TYPE,1
*DO,I,1,16
E,I,I+1
*ENDDO
TYPE,32
real,32
e,2
TYPE,33
real,33
e,3
TYPE,34
real,34
e,4
TYPE,38
real,38
e,26
TYPE,313
real,313
e,13
TYPE,314
real,314
e,14
TYPE,315
real,315
e,15
TYPE,316
real,316
e,16
BRG =0 ! BEARING "LENGTH" FOR VISUALISATION
N,18,0.039,BRG
N,19,0.039,0,BRG
N,20,0.049,BRG
N,21,0.049,0,BRG
N,22,0.1477,BRG
N,23,0.1477,0,BRG
N,24,0.1577,BRG
N,25,0.1577,0,BRG
TYPE,2 ! CREATE BEARING ELEMENTS
REAL,2
E,18,4
E,19,4
E,20,5
E,21,5
TYPE,3 ! CREATE BEARING ELEMENTS
REAL,3
E,22,14
E,23,14
E,24,15
E,25,15
finish
/SOLU
D,18,ALL
D,19,ALL
D,20,ALL
D,21,ALL
D,22,ALL
D,23,ALL
D,24,ALL
D,25,ALL
/SOLU
ANTYPE,MODAL
MODOPT,lanb,20,,,ON
MXPAND,20
SOLVE
finish

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solid45模型

FINISH
/CLEAR
/TITLE,MODAL analysis
/FILENAME,MODAL analysis
/Units,SI !公制单位
/Show
/PREP7
!定义单元类型
ET,1,PLANE42
ET,2,solid45
ET,32,mass21 !mass ux uy uz
keyopt,32,3,4
R,32,0.0248,0.0248,0.0248
ET,33,mass21
keyopt,33,3,4
R,33,0.0577,0.0577,0.0577
ET,34,mass21
keyopt,34,3,4
R,34,0.0577,0.0577,0.0577,
ET,38,mass21
keyopt,38,3,4
R,38,0.134,0.134,0.134
ET,313,mass21
keyopt,313,3,4
R,313,0.0577,0.0577,0.0577
ET,314,mass21
keyopt,314,3,4
R,314,0.0577,0.0577,0.0577
ET,315,mass21
keyopt,315,3,4
R,315,0.02051,0.02051,0.02051
ET,316,mass21
keyopt,316,3,4
R,316,0.06647,0.06647,0.06647
ET,2,COMBIN14 ! ELEMENT TYPE #3 : BEARINGS
keyopt,2,2,2
R,2,164e6
ET,3,COMBIN14 ! ELEMENT TYPE #3 : BEARINGS
keyopt,3,2,3
R,3,164e6
!定义材料属性
MP,DENS,1,7800 !密度
MP,EX,1,2.11e11 !弹性模量
MP,PRXY,1,0.3 !泊松比
R,1,82e6,0,0, , ,0, !实常数
!建模
rectng,0,0.03,0.004,0.008 !!!!!!!!!!!
rectng,0.03,0.034,0.004,0.0085 !!!!!!!!!!!!!
rectng,0.034,0.044,0.004,0.0085
rectng,0.044,0.049,0.004,0.0085
rectng,0.049,0.0555,0.004,0.01025
rectng,0.0555,0.0585,0.004,0.0145
rectng,0.0585,0.065,0.004,0.011
rectng,0.065,0.117,0.004,0.018
rectng,0.117,0.138,0.004,0.011 !!!!!!!!
rectng,0.138,0.143,0.004,0.0085
rectng,0.143,0.153,0.004,0.0085
rectng,0.153,0.164,0.004,0.0085
rectng,0.164,0.187,0.004,0.00625
aadd,all
lesize,1,,,15
lesize,3,,,15
lesize,53,,,3
lesize,7,,,3
lesize,55,,,8
lesize,56,,,8
lesize,57,,,3
lesize,58,,,3
lesize,19,,,5
lesize,59,,,5
lesize,23,,,3
lesize,61,,,3
lesize,27,,,5
lesize,63,,,5
lesize,31,,,26
lesize,65,,,26
lesize,35,,,7
lesize,67,,,7
lesize,39,,,2
lesize,69,,,2
lesize,72,,,5
lesize,71,,,5
lesize,74,,,5
lesize,73,,,5
lesize,51,,,8
lesize,75,,,8
lesize,68,,,3
lesize,70,,,1
lesize,76,,,1
lesize,50,,,1
lesize,54,,,1
lesize,66,,,3
lesize,4,,,2
lesize,60,,,1
type,1
amesh,all
k,53,0,0,0
k,54,0.187,0,0
TYPE,2
MAT,1
!扫掠体
EXTOPT,ESIZE,10,0,
EXTOPT,ACLEAR,1
VROTAT,all, , , , , ,53,54,360,2,
EPLOT
NPLOT
N,300001,0.034,0.0185,0,,,,
N,300002,0.034,-0.0185,0,,,,
N,300003,0.034, 0, 0.0185,,,,
N,300004,0.034, 0, -0.0185,,,,
N,300005,0.044, 0.0185, 0,,,,
N,300006,0.044, -0.0185, 0,,,,
N,300007,0.044, 0, 0.0185,,,,
N,300008,0.044, 0, -0.0185,,,,
N,300009,0.143,0.0185,0,,,,
N,300010,0.143,-0.0185,0,,,,
N,300011,0.143,0,0.0185,,,,
N,300012,0.143,0,-0.0185,,,,
N,300013,0.153,0.0185,0,,,,
N,300014,0.153,-0.0185,0,,,,
N,300015,0.153,0,0.0185,,,,
N,300016,0.153,0,-0.0185,,,,
!
!
n200001=node(0.034,0.0085,0)
n200002=node(0.034,-0.0085,0)
n200003=node(0.034,0,0.0085)
n200004=node(0.034,0,-0.0085)
!
n200005=node(0.044,0.0085,0)
n200006=node(0.044,-0.0085,0)
n200007=node(0.044,0,0.0085)
n200008=node(0.044,0,-0.0085)
!
n200009=node(0.143,0.0085,0)
n200010=node(0.143,-0.0085,0)
n200011=node(0.143,0,0.0085)
n200012=node(0.143,0,-0.0085)
!
n200013=node(0.153,0.0085,0)
n200014=node(0.153,-0.0085,0)
n200015=node(0.153,0,0.0085)
n200016=node(0.153,0,-0.0085)
!
n400001=node(0.022,0.008,0)
n400002=node(0.085,0.0105,0)
n400003=node(0.1574,0.008,0)
n400004=node(0.1755,0.00625,0)
TYPE,32 !建立质量单元
real,32
e,n400001
TYPE,33
real,33
e,n200001
TYPE,34
real,34
e,n200005
TYPE,38
real,38
e,n400002
TYPE,313
real,313
e,n200009
TYPE,314
real,314
e,n200013
TYPE,315
real,315
e,n400003
TYPE,316
real,316
e,n400004
TYPE,3
REAL,1
E,n200001,300001
E,node(0.034,-0.0085,0),300002
E,node(0.034,0,0.0085),300003
E,node(0.034,0,-0.0085),300004
E,n200005,300005
E,node(0.044,-0.0085,0),300006
E,node(0.044,0,0.0085),300007
E,node(0.044,0,-0.0085),300008
E,n200009,300009
E,node(0.143,-0.0085,0),300010
E,node(0.143,0,0.0085),300011
E,node(0.143,0,-0.0085),300012
E,n200013,300013
E,node(0.153,-0.0085,0),300014
E,node(0.153,0,0.0085),300015
E,node(0.153,0,-0.0085),300016
eplot
/solu
!
D,300001,,0,0,300016,1,UX,UY,UZ !定义弹簧单元的外部节点的想x,y,z方向的位移约束
!X=0.034处的弹簧内部节点
D,n200001,,,,,,UX,,,
D,node(0.034,-0.0085,0),,,,,,UX,,,,
D,node(0.034,0,0.0085),,,,,,UX,,,,
D,node(0.034,0,-0.0085),,,,,,UX,,,,
!X=0.044处的弹簧内部节点
D,n200005,,0,,,,UX,,,
D,node(0.044,-0.0085,0),,,,,,UX,,,,
D,node(0.044,0,0.0085),,,,,,UX,,,,
D,node(0.044,0,-0.0085),,,,,,UX,,,,
EPLOT
!
!
/solu
antype,modal
modopt,lanb,10,,, !模态提取方法Method=LANB、SUBSP、REDUC、UNSYM、DAMP、QRDAMP。
mxpand,10
solve
/POST1

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timotheos · 发表于 2013-7-14 05:46

竟然还有人在用古董级单元solid45，我们单位如果再用就不用上班了

ME! · 发表于 2013-7-14 12:50

timotheos 发表于 2013-7-14 05:46

登录/注册后可看大图

竟然还有人在用古董级单元solid45，我们单位如果再用就不用上班了

什么意思，上面的命令流我已经搞好了

游牧人 · 发表于 2013-12-8 15:39

单元的影响不是太大吧

sout · 发表于 2014-3-11 13:30

你好，我目前也出现这种情况，使用solid185和beam188计算固频时出现很大差距，想问下你是如何解决的？谢谢，急用啊

ME! · 发表于 2014-3-17 11:09

本帖最后由 ME! 于 2014-3-17 11:11 编辑

sout 发表于 2014-3-11 13:30
你好，我目前也出现这种情况，使用solid185和beam188计算固频时出现很大差距，想问下你是如何解决的？谢谢 ...

质量单元：对两种梁单元，质量单元都在梁节点，即轴线上；而 solid45 单元模型中，质量单元则偏离了轴线，你要比较三种单元的结果，就要使模型尽量一致，否则难以发现频率不一致的原因。如果质量单元较大，它偏离轴线后，由于几个转动惯量的作用，对频率的影响可能会很大的，再进行结果比较就没有意义了。

solid45 单元的模型中，定义质量单元的 8 个节点都不在轴线上 (y 不等于零)，而梁模型的质量单元都在轴线上，这也是造成频率不同的一个因素。影响多大，要看质量单元的总和与轴本身质量的大小比较。
6 BEAM188 和 SOLID45 单元的模型中，分别定义了 400001~400004 号节点，且在这些节点上定义了质量单元，但是这些节点却没有和其它单元或节点相连，因而他们在发现中将不起作用，总质量小了，频率也就高了。

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[结构分析] ansys模态分析，beam3和beam188，solid45

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