Question

What is the maximum possible radius of a sphere of thickness 1 cm made of a metal with maximum allowable stress as 90 MPa that can hold an internal pressure of 15 MPa without failing ?

• A. 0.24 m
• B. 24 m
• C. 0.12 m
• D. 12 m

Answer 1

Answer:

C. 0.12 m

Given: t = 1cm = 10 mm, $\sigma_{h} = 90 MPa$, p = 15 MPa Circumferential or hoop stress for spherical vessel, $\sigma_h =\frac {pd}{4t} \Rightarrow 90= \frac{15 \times d}{ 4\times10} \Rightarrow d=0.24 m.$ radius,$r = 0.12m$