Determine the minimum thickness required:
A thin spherical shell of 2 m diameter is subjected to an internal pressure of 1.5 N/mm^{2}. If the allowable tensile stress of the material of the shell is equal to 125 N/mm^{2}, determine the minimum thickness required.
Solution
Diameter of the shell, d = 2 m = 2000 mm.
Internal pressure, p = 1.5 N/mm^{2}.
Permissible tensile stress = 125 N/mm^{2}.
If thickness of the shell is t.
After that, we have,
125 = pd /4t = 1.5 × 2000/4t
∴ t = 1.5 × 2000 /4 × 125= 6 mm
∴ Minimum thickness required = 6 mm.