Need answers on tubular structures

[buf006]

Ok so I have been looking over the internet on reading material on structures of tube. From experience I know this happens with items like straws (see illustration below). Is there an actual name of the phenomenon that happens (maybe a few formulas)

If you don't understand the picture from just the drawings feel free to ask and i will try to clarify as much as I can.

 

[buf006]

thanks for the move. i really didn't know where to ask this question.

 

[ank_gl]

Buckling

 

[buf006]

before the buckle. i want to know what it is called when it starts to bend and before it buckles.

 

[nvn]

I agree that ank_gl has given the correct answer to post 1. Regarding your question in post 4,
when the tube starts to bend but before it buckles, this is called bending deflection.

 

[buf006]

I agree that ank_gl has given the correct answer to post 1. Regarding your question in post 4,
when the tube starts to bend but before it buckles, this is called bending deflection.

O ya. i know its buckling when the tubes buckles (haha). With bending deflection isn't that only when a force is applied perpendicularly to the tube and not when applied against the tube?

 

[ank_gl]

O ya. i know its buckling when the tubes buckles (haha). With bending deflection isn't that only when a force is applied perpendicularly to the tube and not when applied against the tube?

I would suggest you to read a chapter about buckling from some good book, or simply http://en.wikipedia.org/wiki/Buckling

Just for a start, compressive failure is way more complex than tensile failure.

 

[nvn]

With bending deflection, isn't that only when a force is applied perpendicularly to the tube?

No, bending deflection occurs when bending moment is applied to the tube, regardless of which
force caused the bending moment.

 

[ank_gl]

& the bending moment can occur due to load eccentricity, material inhomogeneity etc. Compressive failure study is more experimental than theoretical.

 

[Mech_Engineer]

The phenomenon is definitely buckling (a.k.a. elastic instability). You should read about it in a strength of materials textbook. There is a pretty good summary of it here: http://en.wikipedia.org/wiki/Buckling