Oral

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Master of Science in Mechanical Engineering Politecnico di Milano Advanced Machine Design (Prof. S. Beretta) Oral test – 11.09.2025 • Write on your paper the Name, Surname and University ID number. • Save your pdf according your ID number Exercise 1 (2pts) Kth for a given material depends on stress ratio: 1. Explain why 2. What is the typical range for steels and Al alloys when -1<R<0.7 ? Exercise 2 (2pts) Determine the amximum lenght of the piston that would ensure that failure is controlled by plastic colapse SY = 200 MPa UTS = 350 MPa E = 80000 MPa L = 150 mm 30 mm 12 mm P P P Exercise 3 (3pts) 1) According to the provided remote stress, estimate the SIF 2 different crack lengths (a1=0.5 mm, a2=10 mm) and verify if the crack leads to failure KIC = 40 MPa√m Exercise 4 (1pts) Calculate the minimum fracture toughness that ensures a LBB design for the pressure vessel here schematized. Internal pressure p = 20 MPa Diameter Di = 350 mm Wall thickness t = 5 mm