Three solid bar of different materials; aluminium bar AB $,$ steel bar BC and brass bar CD $,$ are connected together. Both end of the bar are fixed supported to the wall. Mechanical properties and cross sectional area of the materials are tabulated in the table. If a load $P=50kN$ acts at point $B$ and temperature is risen by $30C,$ determine:$-$

a$)$ Normal stresses in each bar

b$)$ Horizontal displacement of point B

$\backslash$table$[[$Bar$,E(GPa),(x\frac{{10}^{-6}}{}C),A(m{m}^2)$