21:19 L3 Statics Assignment 3... 4. Two steel plates are riveted together by means of a single lap joint as shown in Figure 3. Six rivets of diameter 9mm are used, and the load carried is 20kN. What is the shear stress in the fastening and the factor of safety in operation if the shear strength is 300MPa? Number of rivets in joint = n F Rivet diameter=d Single shear Figure 3 5. The above single lap joint is replaced by a double strap butt joint with six rivets as shown in Figure 4. If the fastening carries the same shear stress as above, what would be the required rivet diameter? F. Connecting plate Number of rivets in each joint-n Rivet diameter=d Double shear Figure 4 6. The diagram below (Figure 5) shows a jib crane supported by a cable at 30 with a rectangular cross-section beam (60mm x 200mm) of mass 282kg and length 3m. The beam is made from carbon structural steel (ASTM A36 steel) and carries a load of 30kN, 2m from the fixed end. 1. Calculate the total maximum stress in the beam due to the loading and select a wire cable suitable to carry this load (refer Table 3 cable chart). 2. Suggest which physical parameters of the structure can be changed to ensure it is fit for purpose when subject to axial, bending and shear loading. Beam 2m 3m Cable Wire Rope 30 30KN Figure 5 Beam cross-section 60mm 200m