Stability of a column

BEAM4—eight triangles

$u=v=0$ at node 11
$v=0$ at node 27

The unit end force is replaced with the equivalent surface traction as $$q_x=\frac{-1}{0.01\times 0.02}=-5000\text{ Pa},\quad q_y=0\text{ Pa}.$$

The initial stress matrix is then computed from the stress field obtained by the standard linear analysis.

beam56g2.bat

rmd2 beam4g2.i1
rpd2 beam4g2.i2
srh2 beam4g2.i3
fefs beam4g2.i4
geo2 beam4g2.iG
heig beam4g2.iE
stab beam4g2.iS

beam4g2.i1

;  NELEM NNOD ITED  ...  KSS
IP   8    27    4   6*0  -1
;  CRIT SCALE THDEF
RP 1.01   1    0.01
XY N 1:10 X 2*0 2*0.25 2*0.5 2*0.75 2*1
          Y 5*(0 0.02)
EL E 1:8 N =P 1 3 2 =P =Q 12 13 11 =Q =R 3 4 2 =R =S 15 14 13 =S
           =2P =4Q =2R =4S =4P =8Q =4R =8S =6P =12Q =6R =12S
EN
EN

beam4g2.i2

;  KREST
IP   1
         ; E    α ν   ρ
MP 1 T 1 V 2e11 0 0.3 0
SV 1 T 9 V -5000 0 0 ; Fx = -1 N

AS 1 /M 1
  /B 0 N 11 /B 0 C 2 N 27
  /S 1 E 8 S2

EN
EN

beam4g2.i3

;  KREST
IP   1
EN
EN

beam4g2.i4

;  KREST
IP   1
EN
EN

beam4g2.iG

;  ILC
IP  1
EN
EN

beam4g2.iE

;  KREST NROOT NITERX KTPR KEVP
IP   1     1      0     0    1
EN
EN

beam4g2.iS

IP 1
EN
EN

beam4g2.oS

IP 1                                                                            
EN                                                                              
EN                                                                              


                              LOADING PARAMETERS
  0.140350E+04

                                * END OF STAB *
 TOTAL CPU: 00:00:00