QUESTION $3[20$ MARKS$]$

A round steel bar with a diameter of $50mm$ is encased in an aluminium round bar of $50mm$ internal diameter and $60mm$ external diameter. The assembly is $4m$ long and carries an axial tensile load of $200kN.$

$3\mathrm{.}1$ Calculate the stresses in the aluminium and the steel bars.

$3\mathrm{.}2$ Calculate the load on each material.

$[13]$

$3\mathrm{.}3$ Calculate the elongation of the assembly.

$4$

$3$

$E$ for steel $=200$GPa and $E$ for aluminium $=65$GPa

TOTAL: $75$ marks

$($a$)$

UNISA $2024$

$3$