ANSYS柱子稳定分析算例

! ANSYS柱子稳定分析算例

! Example of geometry nonlinear analysis in ANSYS

! 要点：预应力，特征值屈曲，添加初始缺陷，几何非线性分析

! 作者: 陆新征，清华大学土木系

! Author: Lu Xinzheng Dept. Civil Engrg. of Tsinghua University ! last revised: 2003.2.

!

finish

/CLEAR

/UNITS,SI

/PREP7

!*

FORCE=100

OFFSET=0.1 !初始缺陷为0.1

! 建立模型

ET,1,BEAM4

ET,2,LINK10

R,1,0.1*0.12,0.12*0.1**3/12,0.1*0.12**3/12,0.12,0.1, ,

R,2,0.002*0.002,2e-3, !预应力

MPTEMP,1,0

MPDATA,EX,1,,200e9

MPDATA,PRXY,1,,0.27

MPDATA,DENS,1,,7800

k,1,

k,2,0,0,5

k,3,0,0,-5

k,11,0.2,0,0

k,12,-0.2,0,0

k,13,0,0.2

k,15,0,-0.2

l,1,2

l,1,3

l,1,11

l,1,12

l,1,13

l,1,15

l,2,11

l,2,12

l,2,13

l,2,15

l,3,11

l,3,12

l,3,13

l,3,15

lsel,,,,1,6

latt,1,1,1

ALLSEL,ALL

lsel,,,,7,14

latt,1,2,2

ALLSEL,ALL

lsel,,,,1,6

LESIZE,all,0.3, , , , , , ,1

lsel,,,,7,14

LESIZE,all, , ,1 , , , , ,1

ALLSEL,ALL

LMESH,ALL

FINISH

/ESHAPE,1.0

!*

! 求解特征值屈曲荷载

*DO,I,1,100

FINISH

/SOLU

DK,3, , , ,0,UX,UY,UZ, , ,ROTZ ,

DK,2, , , ,0,UX,UY, , , , ,

FK,2,FZ,-FORCE

ANTYPE,0

!设定时间步

TIME,1

AUTOTS,0

NSUBST,1, , ,1

!NLGEOM,1

SSTIF,ON

SOLVE

FINISH

/SOLU

ANTYPE,BUCKLE ! Buckling analysis

BUCOPT,LANB,1 ! Use Block Lanczos solution method, extract 1 mode MXPAND,1 ! Expand 1 mode shape

PSTRES,ON ! INCLUDE PRESTRESS EFFECTS

SOLVE

FINISH

*GET,FREQ1,MODE,1,FREQ

*IF,FREQ1,LT,0.01,THEN

FREQ1=0.01

*ENDIF

*IF,ABS(FREQ1-1),LT,0.01,THEN !如果频率误差小于1% *EXIT

*ENDIF

FORCE=FORCE*FREQ1

*ENDDO

! 添加初始缺陷

FINISH

/POST1

SET,FIRST

NSORT,U,SUM

*GET,DMAX,SORT, ,MAX

!*

FINISH

/prep7

upgeom,OFFSET/DMAX,1,1,beammodel,rst

! 非线性求解

FINISH

/SOLU

!*

FORCE=FORCE*3.

DK,3, , , ,0,UX,UY,UZ, , ,ROTZ ,

DK,2, , , ,0,UX,UY, , , , ,

FK,2,FZ,-FORCE

ANTYPE,0

NLGEOM,1

NSUBST,20,0,0

OUTRES,ALL,1

ARCLEN,1,0,0

AUTOTS,-1.0

SOLVE

! 绘制荷载位移曲线

FINISH

/POST26

FILE

FILE,'beammodel','rst','.'

/UI,COLL,1

NUMVAR,200

FILLDATA,191,,,,1,1

REALVAR,191,191 NUMVAR,200 FILLDATA,191,,,,1,1 REALVAR,191,191

!*

NSOL,2,2,U,Z, UZ_2 STORE,MERGE

!*

RFORCE,3,19,F,Z, FZ_3 STORE,MERGE

XVAR,2

PLVAR,3,