A steel rod of \(25 \mathrm{~mm}\) diameter is placed concentrically in a copper tube of an internal diameter \(38.5 \mathrm{~mm}\) and external diameter of \(41.5 \mathrm{~mm}\). Nuts and washers are fitted on the rod so that the ends of the tube is enclosed by the washers. The nuts are initially tightened to give a compressive stress of \(30 \mathrm{~N} / \mathrm{mm}^{2}\) on the tube and a tensile load of \(45 \mathrm{kN}\) is then applied on the rod. Find the resultant stresses in the tie rod and tube, \(\mathrm{E}_{\mathrm{s}}=205 \mathrm{GPa}, \mathrm{E}_{\mathrm{c}}=80 \mathrm{GPa}\).