Before you start going through equations and trying to solve this I just need a simple question answered about this problem.
1) Is it correct for me to assume that the
pressure on both walls is equal?
If so, I think the normal
stress of the aluminum and steel bars are equal.
Problem:
A circular bar consist of 3in diameter aluminum alloy with Young’s modulus, E = 10,600 ksi, poisson ratio, ν = 0.33, and temperature coefficient, α = 12.5 * 10-6 /°F and 4in diameter steel with Young’s modulus, E = 30,000 ksi, poisson ratio, ν = 0.3, and temperature coefficient, α = 6.6 * 10-6 /°F separated by a rigid piece as shown. The bar is fixed between two rigid end supports and is considered unstressed at 0°F. Determine (a) the normal stress in both the aluminum bar and the steel bar, and (b) the change in diameter of the aluminum and steel bar.
Diagram of Problem 
