The pin-connected structure shown in the figure consists of a rigid beam ABCD and two supporting bars. Bar (1) is a bronze alloy [E = 102 GPa] with a cross-sectional area of A₁ = 200 mm2. Bar (2) is an aluminum alloy [E = 72 GPa] with a cross-sectional area of A2 = 640 mm². All bars are unstressed before the load P is applied; however, there is a 2-mm clearance in the pin connection at A. Assume L₁ = 1880 mm, a = 1060 mm, b = 620 mm, c = 480 mm, and L₂ = 1270 mm. If a load of P = 71 kN is applied at B, determine (a) the normal stresses in both bars (1) and (2). (b) the downward deflection of point A on the rigid bar. (1) L₁ b tc (2) D L2

Narrow bars of aluminum are bonded to the two sides of a thick steel plate as shown. Initially, at T₁ = 70°F, all stresses are zero. Knowing that the temperature will be slowly raised to T₂ and then reduced to T₁, determine (a) the highest temperature T₂ that does not result in residual stresses, (b) the temperature T₂ that will result in a residual stress in the aluminum equal to 58 ksi. Assume aa = 12.8 x 10-6/°F for the aluminum and a = 6.5 × 10-6/°F for the steel. Further assume that the aluminum is elastoplastic with E = 10.9 × 106 psi and ay = 58 ksi. (Hint: Neglect the small stresses in the plate.) Fig. P2.121