Problem

(a) Consider a thin-walled cylindrical tube having a radius of 65 mm that is to be used to...

(a) Consider a thin-walled cylindrical tube having a radius of 65 mm that is to be used to transport pressurized gas. If inside and outside tube pressures are 100 and 2.0 atm (10.13 and 0.2026 MPa), respectively, compute the minimum required thickness for each of the following metal alloys. Assume a factor of safety of 3.5.

(b) A tube constructed of which of the alloys will cost the least amount?

Alloy	Yield Strength, σy (MPa)	Density, ρ (g/cm3)	Unit Mass Cost, ($US/kg)
Steel (plain)	375	7.8	1.50
Steel (alloy)	1000	7.8	2.75
Cast iron	225	7.1	3.50
Aluminum	275	2.7	5.00
Magnesium	175	1.8	16.00