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Master of Science in Mechanical Engineering Politecnico di Milano Course of Machine Design 2 (Prof. S. Beretta, Prof. M. Giglio, Prof.ssa L. Vergani) Written test – 10.09.2020 • Write on your paper the Name, Surname and University ID number. • Save your pdf according your ID number Question 1: Figure 1.a shows a uniform continuous beam clamped at one end, with two roller constraints at points B and C. A concentrated force P is applied at the mid span of AB segment. You are required to: 1. draw the bending diagram along the beam; 2. determine the minimum dimension of the throat for the fillet weld at point A. Assume a shear load of 20 kN and a bending moment of 6000 Nm to act at the clamped section. Consider an I-beam cross section of HE180A (refer to the table in the compendium), with the fillet welds positioned as shown in the Figure 1.b. The beam and plate are both made of S275 (Fe430). Figure 1.a Figure1.b Question 2: A socket wrench is used to fasten the bolts as shown in the below figure. The shaft of the wrench has been shot peened to induce compressive residual stresses of -50 MPa. During operation it is subjected to a pulsating vertical force of F = 350 N. You are required to: 1. perform the fatigue assessment of the shaft; 2. determine the number of cycles to failure for the shaft under the applied loads. ms = 0.80 md = 0.9 q = 0.9 UTS = 250 MPa Figure 2 Question 3: Consider a plate with a central hole characterized with an elastic stress concentration factor of Kt=2.5. The plate is made of a material with perfectly elastic-plastic stress-strain curve (σY = 350 MPa and E = 200000 MPa). You are required to estimate the residual stresses and strains at the notch if the plate is loaded to a nominal stress S, and then unloaded. Perform the calculations considering…