understanding buckling result

[giorgio.demurtas]

Hello,

it is the first time I use the buckling module in Fusion360.

I have set-up a model with a 40x40x2 mm steel tube, 3m long, with a 10 kN force on top. I solved it in the cloud.

I understand the bucling phenomenon but I am not sure on how to interpret the results of Fusion360. I get 3 buckling modes:

Mode 1: 0.73 x Load

Mode 2: 0.74 x Load

Mode 3: 6.6 x Load

For any of them, a max displacement of 1 mm.

So, what does it mean? Is my steel tube holding and what is the safety margin?

Attached the file, a screenshot, and an image of the crane I would like to make (the tube is one of the four legs).

[henderh]

Hi Giorgio,

The results consist of a load multiplier + mode shape.

The load multiplier tells you how much of the total applied load will be be needed in order to buckle in that mode.  It can be thought of as a kind of safety factor.  In your example, for the 1st mode, the structure will take only 73% of the applied load to cause it to buckle.

About the displacement, it is a normalized value (not an actual length).  The mode shape is for visualization purposes.

Another way to set up a buckling study (for easy interpretation) is to use a unit load magnitude.  e.g. apply a 1 Newton load and the multiplier results will tell you exactly how many Newtons the structure will take before it buckles.

Hope this helps!

Best regards,

[giorgio.demurtas]

It is clear now. Thanks for the tip!

[blackcatforge55]

What is the difference between Mode 1, Mode 2, and Mode 3?