aluminum alloy $E=10,900$ksi;$=12\mathrm{.}7\frac{{10}^{-6}}{}F$ pipe $(2)$ with a cross$-$sectional area of $A_2=3\mathrm{.}80in.{?}^2.$ The assembly $($shown in the figure$)$ is connected to rigid supports at A and $C.$ It is initially unstressed at a temperature of $85F.$ Assume $L_1=106$ in$.,L_2=132$ in$.,P=36$ kips.

$($a$)$ At what temperature will the normal stress in steel pipe $(1)$ be reduced to zero?

$($b$)$ Determine the normal stresses $($positive if tensile, negative if compressive$)$ in steel pipe $(1)$ and aluminum pipe $(2)$ when the temperature reaches $-18F.$

Answers:

$($a$)T=F$

$($b$){}_1=$ ksi ${}_2=$ ksi