Learning Forum

[Nicholas Nicholas]

Hello, I am new to ansys and I am trying to calculate the buckling load of the strut of this structure. (The labelled parts when joined together basically.)

 

 

The steps performed are shown below, as well as the Location, Magnitude (45N), and direction of Force and location of the fixed constraint.​

5 modes were obtained from the analysis. –ve Load multiplier represents tension instead of compression force. ​ From this analysis, the critical buckling load is found to be 45N*16.076=723.015N (72kg). Have I made a mistake? The value appears to be too high for this structure to possibly withstand

 

 

A simple solidwork buckling analysis shows a load factor of 3.8317. This means the critical buckling load is 45*3.8317= 172.4265N

 

 

Why is there such a huge difference in load factor when the material properties, force magnitude, and location of fixed constraint are the same?​ Just for reference, the tube is 80cm long and has a 1.5cm diameter

[Saurabh Patil]

Hi 

Can you check if you are getting similar eigen mode shapes in both the softwares?

 

[Nicholas Nicholas]

I decided to run the simulation again with the same setup, this time by regenerating the eigenvalue buckling solutions. Interestingly, the results were different, as you can see below. Subsequent regeneration attempts remained consistent. The load factors are now closer to what solidworks calculated previously

 

I'm not entirely certain about the steps required to visualize the eigen mode shapes in SolidWorks, but here's what I attempted: I ran a frequency analysis to calculate its natural frequencies and the corresponding mode shapes. However, I encountered an error when attempting to run it with a 45N force applied. I did manage to run it successfully with a 1N force, and these are the results I obtained.

[Nicholas Nicholas]

Sorry this is the new buckling load. 

 

[Nicholas Nicholas]

Another question, Total Deformation tab show that the Strut attachment piece only deforms down which makes sense. But Mode 4 and and 5 of eigenvalue buckling shows that the Strut attachment piece deforming up above the original position despite having applied a force downwards.Why is this so?