Statically Indeterminate Problem

[wisper]

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.

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[FredGarvin]

Since the stresses are inversely proportional to area and Young's, the two members will not have the same stresses.

 

[wisper]

Thank you.

 

[enigma]

The force is the same through the entire section, but not the pressure.