Question $2$

Two loads are applied to frame structure as shown in Figure Q$2.$ Knowing that the frame and all connection pins are made of steel, determine

$($a$)$ the diameter of the pin at A$,$ B$,$ D and E$.$ Provided that the diameter of pin at A$,$ B and E is the same, and ultimate shearing stress of pins is $395$ MPa $.$

$($b$)$ the required thickness of the bracket supports at D $,$ knowing that the allowable bearing stress of the steel used is $240$ MPa $.$

Given the factor of safety with respect to shear is $3\mathrm{.}1$

Figure Q$2$