有预应力的大变形模态分析

1000521

本人在做柔性附着塔机塔身的模态分析时遇到如下问题：
前2阶振型，塔机的塔身还有变形，以后振型就只剩下钢丝绳的变形，这是为什么，请教高手.谢谢.
一下是命令流：
FINISH
/CLEAR
/FILNAME,Hydranlic Jacking Flat Bridge
/TITLE,The Analysis of Hydranlic Jacking Flat Bridge
instr=0.000335

/PREP7
ET,1,BEAM188                  ! 定义第1类单元是三维梁单元BEAM188
MP,EX,1,210E3                 ! 定义第1类材料的弹性模量EX=210GPa（Q345）
MP,PRXY,1,0.3                 ! 定义第1类材料的泊松比PRXY=0.3
MP,DENS,1,7850e-12            ! 定义第1类材料的密度DENS=7850 kg/m^3

ET,2,LINK10
KEYOPT,1,3,0
R,1,PI*(18)**2,INSTR
MP,EX,2,120E3                 ! 定义第1类材料的弹性模量EX=210GPa（Q345）
MP,PRXY,2,0.3                 ! 定义第1类材料的泊松比PRXY=0.3
MP,DENS,2,7850e-12

MAT,1
SECTYPE,1,BEAM,HREC      !(桥身标准节尺寸)
SECDATA,135,135,10,10,10,10
SECTYPE,2,BEAM,CTUBE     !定义桥身标准节直腹杆单元尺寸
SECDATA,24,30,18
SECTYPE,3,BEAM,CTUBE     !定义桥身标准节斜腹杆单元尺寸
SECDATA,30,38,18


!定义桥身标准节上的节点
N,1,825,0,-825       $  N,2,825,0,825           $  N,3,-825,0,825
N,4,-825,0,-825      $  N,5,825,50,-825         $  N,6,825,50,825
N,7,-825,50,825      $  N,8,-825,50,-825        $  N,9,825,1250,-825
N,10,825,1250,825    $  N,11,-825,1250,825      $  N,12,-825,1250,-825
N,13,825,2450,-825   $  N,14,825,2450,825
N,15,-825,2450,825   $  N,16,-825,2450,-825
N,17,825,2500,-825   $  N,18,825,2500,825
N,19,-825,2500,825   $  N,20,-825,2500,-825
NGEN,27,20,ALL,,,0,2500,0,1

! 定义桥身标准节的外框杆件
MAT,1
SECNUM,1
E, 1, 5           $          E, 2, 6           $          E, 3, 7
E, 4, 8           $          E, 5, 9           $          E, 6, 10
E, 7, 11           $          E, 8, 12           $          E, 9, 13
E, 10, 14           $          E, 11, 15           $          E, 12, 16
E, 13, 17           $          E, 14, 18           $          E, 15, 19
E, 16, 20  
EGEN,27,20,1,16

!定义桥身标准节直腹杆
SECNUM,2
E, 5, 6           $          E, 9, 10           $          E, 13, 14
E, 6, 7           $          E, 10, 11           $          E, 14, 15
E, 7, 8           $          E, 11, 12           $          E, 15, 16
E, 5, 8           $          E, 9, 12           $          E, 13, 16
EGEN,27,20,433,444


!定义桥身标准节斜腹杆
SECNUM,3
E, 5, 10           $          E, 10, 13           $          E, 6, 11
E, 11, 14           $          E, 7, 12           $          E, 12, 15
E, 8, 9           $          E, 9, 16          $          E, 5, 7
E, 9, 11           $          E, 13, 15          
EGEN,27,20,757,767
NUMMRG,ALL
NUMCMP,ALL

CSYS,5
N,1001,5583,45,37500   
N,1002,11166,45,37500  
N,1003,16749,45,37500
N,1004,22332,45,37500
N,1005,27915,45,37500
N,1006,33498,45,37500
N,1007,39081,45,37500
N,1008,44664,45,37500
N,1009,50247,45,37500
N,1010,55830,45,37500

N,1011,5583,-45,37500
N,1012,11166,-45,37500
N,1013,16749,-45,37500
N,1014,22332,-45,37500
N,1015,27915,-45,37500
N,1016,33498,-45,37500
N,1017,39081,-45,37500
N,1018,44664,-45,37500
N,1019,50247,-45,37500
N,1020,55830,-45,37500

N,1021,1340,135,37500
N,1022,2680,135,37500
N,1023,4020,135,37500
N,1024,5360,135,37500
N,1025,6700,135,37500
N,1026,8040,135,37500
N,1027,9380,135,37500
N,1028,10720,135,37500
N,1029,12060,135,37500
N,1030,13400,135,37500
  
N,1031,1340,-135,37500
N,1032,2680,-135,37500
N,1033,4020,-135,37500
N,1034,5360,-135,37500
N,1035,6700,-135,37500
N,1036,8040,-135,37500
N,1037,9380,-135,37500
N,1038,10720,-135,37500
N,1039,12060,-135,37500
N,1040,13400,-135,37500



N,1041,4869,45,65000  
N,1042,9738,45,65000  
N,1043,14607,45,65000  
N,1044,19476,45,65000  
N,1045,24345,45,65000   
N,1046,29214,45,65000   
N,1047,34083,45,65000  
N,1048,38952,45,65000  
N,1049,43821,45,65000  
N,1050,48690,45,65000  

N,1051,4869,-45,65000  
N,1052,9738,-45,65000  
N,1053,14607,-45,65000  
N,1054,19476,-45,65000  
N,1055,24345,-45,65000   
N,1056,29214,-45,65000   
N,1057,34083,-45,65000  
N,1058,38952,-45,65000  
N,1059,43821,-45,65000  
N,1060,48690,-45,65000

N,1061,627,-135,65000
N,1062,1254,-135,65000
N,1063,1881,-135,65000
N,1064,2508,-135,65000
N,1065,3135,-135,65000
N,1066,3762,-135,65000
N,1067,4389,-135,65000
N,1068,5016,-135,65000
N,1069,5643,-135,65000
N,1070,6270,-135,65000


N,1071,627,135,65000
N,1072,1254,135,65000
N,1073,1881,135,65000
N,1074,2508,135,65000
N,1075,3135,135,65000
N,1076,3762,135,65000
N,1077,4389,135,65000
N,1078,5016,135,65000
N,1079,5643,135,65000
N,1080,6270,135,65000
CSYS,0
!在建8个点
N,1101,825,37500,-825   
N,1102,825,37500,825     
N,1103,-825,37500,825
N,1104,-825,37500,-825

N,1105,825,65000,-825   
N,1106,825,65000,825     
N,1107,-825,65000,825
N,1108,-825,65000,-825

TYPE,2
REAL,1
MAT,2
!第一层第1根钢丝绳
E,1101,1001 $ E,1001,1002  $ E,1002,1003  $ E,1003,1004  $ E,1004,1005 $  E,1005,1006 $ E,1006,1007
E,1007,1008 $ E,1008,1009  $ E,1009,1010  
!第一层第2根钢丝绳
E,1102,1011 $ E,1011,1012  $ E,1012,1013  $ E,1013,1014  $ E,1014,1015 $  E,1015,1016 $ E,1016,1017
E,1017,1018 $ E,1018,1019  $ E,1019,1020  

!第一层第3根钢丝绳
E,1104,1021 $ E,1021,1022  $ E,1022,1023  $ E,1023,1024  $ E,1024,1025 $  E,1025,1026 $ E,1026,1027
E,1027,1028 $ E,1028,1029  $ E,1029,1030

!第一层第4根钢丝绳
E,1103,1031 $ E,1031,1032  $ E,1032,1033  $ E,1033,1034  $ E,1034,1035 $  E,1035,1036 $ E,1036,1037
E,1037,1038 $ E,1038,1039  $ E,1039,1040



!第二层第1根钢丝绳
E,1105,1041 $ E,1041,1042  $ E,1042,1043  $ E,1043,1044  $ E,1044,1045 $  E,1045,1046 $ E,1046,1047
E,1047,1048 $ E,1048,1049  $ E,1049,1050


!第二层第2根钢丝绳
E,1106,1051 $ E,1051,1052  $ E,1052,1053  $ E,1053,1054  $ E,1054,1055 $  E,1055,1056 $ E,1056,1057
E,1057,1058 $ E,1058,1059  $ E,1059,1060
!第二层第3根钢丝绳
E,1107,1061 $ E,1061,1062  $ E,1062,1063  $ E,1063,1064  $ E,1064,1065 $  E,1065,1066 $ E,1066,1067
E,1067,1068 $ E,1068,1069  $ E,1069,1070
!第二层第4根钢丝绳
E,1108,1071 $ E,1071,1072  $ E,1072,1073  $ E,1073,1074  $ E,1074,1075 $  E,1075,1076 $ E,1076,1077
E,1077,1078 $ E,1078,1079  $ E,1079,1080

CP,1,UX,241,1101
CP,2,UY,241,1101
CP,3,UZ,241,1101

CP,4,UX,242,1102
CP,5,UY,242,1102
CP,6,UZ,242,1102

CP,7,UX,243,1103
CP,8,UY,243,1103
CP,9,UZ,243,1103

CP,10,UX,244,1104
CP,11,UY,244,1104
CP,12,UZ,244,1104


CP,13,UX,417,1105
CP,14,UY,417,1105
CP,15,UZ,417,1105

CP,16,UX,418,1106
CP,17,UY,418,1106
CP,18,UZ,418,1106

CP,19,UX,419,1107
CP,20,UY,419,1107
CP,21,UZ,419,1107

CP,22,UX,420,1108
CP,23,UY,420,1108
CP,24,UZ,420,1108


D,1,ALL,0
D,2,ALL,0
D,3,ALL,0
D,4,ALL,0

D,1010,ALL,0
D,1020,ALL,0
D,1030,ALL,0
D,1040,ALL,0

D,1050,ALL,0
D,1060,ALL,0
D,1070,ALL,0
D,1080,ALL,0

FINISH
/SOLU
ANTYPE,0
ACEL,0,9800,0
F,433,FY,-121000  $  F,434,FY,-121000
F,435,FY,-121000  $  F,436,FY,-121000
F,435,FX,5733     $  F,436,FX,5733
TIME,1
NUSUB,10,20,5
OUTRES,ALL,ALL

SSTIF,ON
PSTRES,ON
ALLS
SOLVE
FINI




/SOLU
ANTYPE,2
MODOPT,LANB,20
MXPAND,20,,,0
ACEL,0,9800,0
PSTRES,1

ALLS
SOLVE
SAVE
FINI
希望大家帮我解决一下！！！！！！