Finding the elastic modulus of a metal in a mixed phase

[joemmonster]

Homework Statement

If a metal is adhered to a surface of another metal, let's say copper is plated onto aluminum, how can the elastic modulus of copper can be extracted given only the data of the thickness of the copper and aluminum, the young's modulus of the combined metal and the modulus of the copper.

Homework Equations

Young's modulus equation is the only thing i can think of which is E = Stress/Strain

The Attempt at a Solution

Tried to plug in the values by breaking down the stress into F/A = (F/L*W) in which W is the thickness of copper and aluminum but the moduli left untouched.

 

[Dr.D]

Looking at your example, copper plated onto aluminum, I think you are hoping for too much. A plated film is not going to have significant influence on the mechanical properties of an aluminum bar.

Now if the plated film and the aluminum base are of comparable thickness, you might envision a tensile test that would give some information. Presumably, the two films would both suffer identical strain in the tensile test, so you could treat this the same way that rebar in a concrete beam is treated. It will be a bit awkward since the thing you want to discover is the Young's modulus for the copper, but it should be possible.