QUESTION $4$: ENERGY METHODS: TRUSSES $($SDS$)$

Consider the truss shown in the figure below. Truss members AD and DE are subjected to

temperature increase by $40C$ while member CE's temperature is decreased by $30C.$ In addition,

member BE is fabricated $5$ mm short. Find the vertical displacement of point B using the method

of virtual work. Take $A=2500m{m}^2,E=200$GPa and $a=1\mathrm{.}2\frac{{10}^{-6}}{}C$ for all members.