1. Two plates 16 mm thick are joined by a double riveted lap joint. The pitch of each row of rivets is 90 mm. The rivets are 25 mm in diameter. The permissible stresses are as follows : o, = 140 MPa;t = 110 MPa and 0. = 240 MPa. Find the efficiency of the joint. [Ans. 53.5%]

Problem 3. Strains are measured on the surface of a structural component as &A = = 1200 x 10-6. EB = 500 x 10-6, &c = 300 × 10-6. E = 200 GPa and v = 0.3. b) a) Find the principal stresses and show these on a sketch of a properly oriented element. Use Mohr's Circle to find the stresses at 0 = 30° counterclockwise from the x axis and show these on a sketch of a properly oriented element. y 60° C B A X

20 (B) An air vessel, which is made of steel in 2 m long. It has an external diameter 44 cm and is 2 cm thick. 1. Calculate the permissible pressure difference allowed between the inside and outside if the longitudinal stress in the wall must not exceed 20 MPa. 2. Determine longitudinal and hoop strains. 3. Calculate the change in diameter and change in volume. Take E = 200 GPa and v = 0.3

Figure 2 shows a bar with a length L fixed at the left end. Question 2 The uniformly distributed force f (unit: N/m) is applied along the axis of the bar, and a concentrated force P (unit: N) is applied at the free end of the bar. The bar has a constant Young's modulus E and cross-section area A. Find the stretch of the bar: (a). at the free end of the bar; (b). at the center of the bar. (Expressing all the resulta with E, A, L, f, and P). E, A L Fig. 2. The kft end of the bar is fd, ad the froe ed of the bar is applied with a force P. The uniformly distribatod kece f is applied akong the ais of the bar.