An aluminum cylinder with a steel wire attached

[Dingleberg]

Hi! So when this system gets heated, how does the wire expand if it is bent like that? Would it expand horizontally or vertically? Also, when calculating the stress for the wire, I know that I use the thermal expansion equation for dL of steel, but other people said that you have to also subtract that by dL of aluminum, why? I can't picture that in my head for some reason.

My process was:

Stress in wire = Y(αΔT)
and the answer I got was 2.4*10^7 N/m^2

 

[Nidum]

You have to assume that the short cross pieces of wire do not bend . Just treat them as very strong brackets .

 

[Dingleberg]

You have to assume that the short cross pieces of wire do not bend . Just treat them as very strong brackets .

Oh all right, but why does the cylinder affect the steel wire if this is a linear expansion? It does not push the brackets or steel wire in any sort of way.

Thank you for your response by the way :)

 

[Nidum]

Is the coefficient of expansion for Aluminium more or less than that for steel ?