How Does Stress Affect a Hollow Pipe When Force Is Uniformly Applied?

[Mohmmad Maaitah]

Homework Statement

Determine the average normal stress on the cross
section. Sketch the normal stress distribution over the
cross section.

Relevant Equations

σ = F/A

Hi, I've problem thinking about this problem
isn't the force acting on "nothing"?
how can there be any stress, I'm lost!

 

[berkeman]

Is there more to the problem statement? What is that a sketch of? Is it a cylinder of one material inside a pipe of another material? Or a hollow pipe with the force applied uniformly across the top surface of the hollow pipe?

 

[Mohmmad Maaitah]

hollow pipe with the force applied as in the picture, that's my problem, it's not clear enought to me

 

[berkeman]

Others may have better replies than mine, but my interpretation is that the total force shown is applied uniformly across the exposed top area of the hollow pipe. Kind of like a thick steel plate were pressing down on the top of the pipe with that total force. Can you show us your work for that situation?

 

[Lnewqban]

Homework Statement: Determine the average normal stress on the cross
section. Sketch the normal stress distribution over the
cross section.
Relevant Equations: σ = F/A

Hi, I've problem thinking about this problem
isn't the force acting on "nothing"?
how can there be any stress, I'm lost!

It is important not to confuse a force with its representation.
Note that the question is in reference to a specific cross section.
Nothing indicates that the compressing load is applied at that specific section.

Any load is felt by the material resisting it as a chain reaction from molecule to molecule.
The normal calculation in these cases is directed to determine what group of molecules are feeling the higher value of stress, which may or not surpass their bonding forces, leading to a failure.

 

[Chestermiller]

They expect you to assume that the compression force is distributed uniformly over the cross section of inside radius 80 mm and outside radius 100 mm.

 

[Mohmmad Maaitah]

Others may have better replies than mine, but my interpretation is that the total force shown is applied uniformly across the exposed top area of the hollow pipe. Kind of like a thick steel plate were pressing down on the top of the pipe with that total force. Can you show us your work for that situation?

I didn't do any work because expect saying "it's zero".
I got it know, thank you all!