Question $1$

A uniform circular solid rod, without notches, has two $\backslash (90^\{\backslash$circ$\}\backslash )$ bends and supports a constant force of $8$ kN $,$ as shown in the sketch. The rod is made from a ductile material with a tensile yield strength of $267$ MPa $.$ Using the von Mises theory, determine the minimum rod diameter $($in mm $)$ required for a safety factor of $1\mathrm{.}5$ at the most critical section. Do not consider the transverse shear stress.

Give your answer in millimeters with $1$ digit after the decimal point.