Buckling Analysis Control

 

 

 

Enter the load cases and related data for the buckling analysis of a structure.

 

MIDAS/Gen follows the procedure noted below for buckling analysis. [Details...]

 

 

 

From the Main Menu select Analysis > Buckling Analysis Control.

 

 

 

03-BAC-2.jpg

0-Check.jpg Buckling Modes

 

Number of Modes: Enter the number of buckling modes.

 

Positive Value Only: Produce the eigenvalue results only for the loading direction.

 

Note
Once buckling analysis is performed, buckling modes are computed for both the loading direction and the opposite direction. However, for static loads whose loading direction is fixed, it is not necessary to compute the buckling mode shape and factor for the opposite direction.

Search: Calculate the buckling load factor within the defined range.

From: Minimum value of the buckling load factor

To: Maximum value of the buckling load factor

Note

If the same values are entered in the 'From' and 'To' field, the buckling load factors closest to the entered value are calculated.

Sturm Sequence Check: Check to detect any missed buckling load factors. If there are any missed buckling load factors, an error message is displayed in the message window.

0-Check.jpg Frame Geometric Stiffness Option

Option for formulating the geometric stiffness matrix in a frame member

Consider Axial Force Only : Consider axial force only when formulating the geometric stiffness matrix.

 

0-Check.jpg Buckling Combination

Enter the load cases for the buckling analysis. Different Load Cases with the corresponding Scale Factors may be entered.

Load Type

Variable: Consider increase or decrease in loads (live loads, etc.)

Constant: Do not consider increase or decrease in loads (self-weight, dead loads)

Note
Strictly speaking, Constant should contain only the self-weight of the structure. However, it is common to apply dead load to slab, along with the self-weight. Accordingly, dead load can be entered as Constant Type.

0-rectangle.jpgTo enter a new or additional load case

Enter the Load Case and Scale Factor; then click 0-Add.jpg.

0-rectangle.jpgTo modify the scale factor for a previously entered load case

Select the load case, modify the Scale Factor and click 0-Modify.jpg.

0-rectangle.jpgTo delete a previously entered load case

Select the load case to be deleted from the load case list at the bottom of the dialog box and click 0-Delete.jpg.

0-Check.jpg Remove Buckling Analysis Data

To delete all the entered data, click 03-BAC-3.jpg.

Note

Buckling Analysis may not be carried out in conjunction with P-Delta Analysis or Eigenvalue Analysis. Buckling Analysis is limited to truss element, beam element (including tapered beam element) and plate elements.