The Linear Static and Buckling Analysis is one of the analysis methods that SkyCiv offers to solve your structure.
SkyCiv users often enquire about why the software only returns a single buckling factor, thinking that there should be a factor for each member. However, SkyCiv performs a rational elastic buckling analysis via an eigenvalue analysis, meaning that buckling is considered for the entire structure, groups of members and individual members. This way, the entire stiffness of the model is factored into its buckling susceptibility.
The critical load of each member is also determined during the analysis. This is the load at which a certain member will buckle. The critical load is proportional to the Young’s Modulus and Moment of Inertia, and inversely proportional to the length of the member. Critical load is not a function of Yield Strength.
Smoother Buckling Shape
By default a simplified buckling shape is solved by the software when the structure is buckling, or close to buckling. If you’re interested in solving a more accurate buckling shape then please enable the Smoother Buckling Shape setting found in the Settings of the software. Please note that enabling this option will increase the solve time.
Extra Notes and Considerations
- This buckling analysis only considers Euler Buckling due to axial compression. Torsional buckling is not considered.
- If an extremely low buckling load factor is found by the software (i.e. less than 0.05) then this could be due to the model being unstable. Hence, you should look at the stability of the model as it could be the problem rather than buckling. Check your member-end fixities and supports. Often excessive deflections can be a hint that these instabilities exist too.
- This buckling analysis only applies to members, not plates.
Example: Buckling of a Vertical Column
1) Consider a vertical member that is 3 feet tall with a rectangular cross section that is 1 inches by 2 inches made from the default Structural Steel material in SkyCiv Structural 3D. It is fully fixed at the base of the column and experiencing a 1 kip compressive point load.