Transformation of Stress (Mech. Materials)

[Litcyb]

Homework Statement

Question is attached

Homework Equations

σ(x) = 0
σ(y)= P/A
t(xy)= Tc/j

The Attempt at a Solution

I know how to do the stress transformation, but my only issue is noticing why σ(x)= 0, I can't see it, can someone help me.

 

[Chestermiller]

Homework Statement

Question is attached

Homework Equations

σ(x) = 0
σ(y)= P/A
t(xy)= Tc/j

The Attempt at a Solution

I know how to do the stress transformation, but my only issue is noticing why σ(x)= 0, I can't see it, can someone help me.

I assume that x is the thickness direction. Is that correct? If so, then the stress in the x direction is zero, because both surfaces of the pipe are in contact with the air (and the wall thickness is small compared to the lateral dimensions of the pipe).

Chet