5_Buckling analysis

Buckling is important concept in stuctural engineering.

A material or structure that deforms or failure under compressive forces. 

Buckling is most commonly observed in slender and long structural element like columns or beams, which bend or curve outward when unable to withstand the applied compressive forces.

 

source : WIkipedia

 

First, compute the analytic solution.

critical load

where $n$ is mode number, $E$ is Young's modulus and $I$ is moment of inertia

First, calculate the critical load for the mode number.

 

Area : square (150mm * 150mm)

T : 10mm

L : 3000mm

E : 70GPa

I : $1.8386 \times {10^{ - 5}}{m^4}$

 

Run HyperMesh and drow lines (3000, 0, 0)

Create - Materials

Card Image : MAT1

E : 70000

NU : 0.33

 

Create - Beamsection

Section Type : BOX

DIM1 : 150

DIM2 : 150

DIM3 : 10

DIM4 : 10

 

Create - Property

Card Image : PBAR

Assign material ans beamsection

property

assign property to components

 

1D - elem types

bars : CBAR

update and return

 

1D - line mesh 

element config : bar2

element size : 100

Components : (0, 1, 0)

mesh and return 

 

Create - Load Collectors

name : spc

 

BCs - Create - Constraint

check all dof and select left node

The rightmost node constrains except in the direction of the load. (check dof2 and 3)

Constrain the remaining nodes to move only in the xy plane. (check dof3)

constraint

Create - Load Collectors

name : force

BCs - Create - Force

magnitude : -160e3

direction : x-axis

force

 

Create - Load Collectors

name : EIGRL

Card Image : EIGRL (Set parameters for eigenvalue analysis)

V1(frequency range lower limit) : 0

ND(Number of modes want to find) : 5

 

Create - Load Step

name : Linear Static

Analysis type : Linear Static

SPC : (1)spc

LOAD : (2)force

 

Create - Load Step

name : Linear buckling

Analysis type : Linear buckling

STATSUB(BUCKLING) : (1)Linear Static

METHOD(STRUCT) : (3)EIGRL

 

Analysis - OptiStruct

 

 

The error rate was very low compared to the analytic solution.