Question $3(25$ Points$)$:

The rigid beam ABC is simple supported at $B$ and it rests on the aluminum member $CD.$ The steel link $AE$ is attached to the rigid beam at $A$ by a pin. Cross section area of the link $AE$ is $1000m{m}^2$ and of the aluminum member $CD$ is $1500m{m}^2.$ The initial temperature of the aluminum member $CD$ is $23C.$ Knowing that there wasn't any stress on the members at initial temperature, determine the force acting on the link $AE$ if the temperature of the aluminum member $CD$ is raised to $60C.$ Neglect the weight of the beam. $E_{st}=200$GPa,${}_{st}=17,3\frac{{10}^{-6}}{}C,E_{sl}=75$GPa,${}_{31}=23\frac{{10}^{-6}}{}C.$