What is the difference between short and long wavelength buckling?

[tugni925]

In general, what is meant by wavelength buckling?

 

[SWComposites]

The length of the buckle deformation. Like vibration mode shape.

 

[Compositepro]

A buckle looks like a wave. There can be one wave between two pinned points, or two or more. It takes more energy to form two waves than one so the one wave is a lower energy state. It requires some other constraint, such as a brace near the center node to get two waves.

 

[FEA way]

To understand this, it is best to study the buckled shapes of simple beams. Probably the best resource in this topic is Timoshenko’s classic "Theory of elastic stability".

 

[tugni925]

So short wavelength buckling would correspond to two waves between the pinned points, and long wavelength correspond to one wave between the pinned points?

 

[SWComposites]

No, two waves could still be “long”.

 

[tugni925]

Like this?

 

[SWComposites]

Upper right could be a short wave, though typically is even short compared to structures length. Lower left is still a long wave. Why is this an issue?

 

[rb1957]

long wave buckling is like euler buckling, buckling of the gross section (possibly with multiple nodes, as shown above).

short wave buckling is crippling.

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