How can I impart imperfections in apdl and do the non linear analysis

[Showkat Ahmad]

I need to impart the first buckling mode as the imperfections in a beam and perform the non-linear analysis of a steel I section In ANSYS APDL. How can I do the same?

 

[Erik Panos Kostson]

See search upgeom command and you will get a lot of examples. Also provide us with the some info as per your previous post do we can look at the nonconvergene issue, otherwise we can not help you

Small example on a beam:

/prep7
!*  
ET,1,BEAM188
!*  
KEYOPT,1,1,0
KEYOPT,1,2,0
KEYOPT,1,3,2
KEYOPT,1,4,0
KEYOPT,1,6,0
KEYOPT,1,7,0
KEYOPT,1,9,0
KEYOPT,1,11,0   
KEYOPT,1,12,0   
KEYOPT,1,15,0   
!*  
K,1,0,0,0   
K,2,2,0,0   
  
L,1,2   

MAT,1   
MP,EX,1,200E9   
MP,NUXY,1,0.3   
!*  
MPTEMP,,,,,,,,  
MPTEMP,1,0  
MPDE,EX,1   
MPDE,NUXY,1 
MPDATA,EX,1,,2E+11  
MPDATA,NUXY,1,,0.3  
SECTYPE,   1, BEAM, RECT, , 0   
SECOFFSET, CENT 
SECDATA,0.05,0.05,0,0,0,0,0,0,0,0,0,0   
 
SAVE

LESIZE,ALL,0.1
LMESH,ALL   
SAVE
FINISH  
/SOL
!*  
ANTYPE,0
FLST,2,1,3,ORDE,1   
FITEM,2,1   
!*  
 
DK,1, ,0, ,0,ALL, , , , , ,  
 

FK,2,FX,-1   
/STATUS,SOLU
SOLVE   

FINISH  
/SOLUTION   
ANTYPE,1
!*  
!*  
EXPASS,0
!*  
BUCOPT,LANB,5,0,0,CENTER
/STATUS,SOLU
SOLVE   

/prep7
UPGEOM,0.0001,1,1,file,rst

/SOL
!*  
ANTYPE,0

SOLVE