Consider two circular rods C-A and A-B shown in Figure 4.1 below. The two members are connected by a double shear pin at A. Two ends of the assembled structure are pined to walls at Band C by single shear pins. An external force of 3 kN is applied at point D and three external forces(2.5 kN, 4.5 kN, and 2 kN) are acting at point A as shown in the figure. Note that a 2.5-kN force is in the direction of member A-B. a) Draw the appropriate internal force diagram between C and A. b) Determine the diameters of rods C-D and A-B so that the maximum average normal stresses in each rod do not exceed 150 MPa in either tension or compression.

Fig: 1

Fig: 2

Fig: 3

Fig: 4