WrittenTest January 23 2024

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Course of Aerospace Structures Written test, January 23 th, 2024 Name Surname Person code: Exercise 1 The figure represents a semi-monocoque model of a fuselage trunk of length2l. It has three circular frames, each with outer radiusr1 and inner radius r2, and eight uniformly spaced stringers, each with concentrated area A. The outer cylindrical thin panel thickness is equal tot. The panel is connected to the central frame by means of sixteen uniformly spaced rivets, each with shank diameterd, and repre- sented by the red dots in the figure. The outer cylindrical thin panel in continuous across the central rib (there is not a junction between a “forward” and “rear” panel), thus the rivets do only connect the rib to the continuous panel. The fuselage is transmitting a constant torsional momentMz. Compute the shear stress in the rivet shank highlighted by the red arrow. (Unit for result: MPa) Data r1 = 1.5 m r2 = 1.45 m l = 1 m d = 3 mm A = 10 cm 2 t = 1.5 mm Mz = 15000 N m Answer Exercise 2 The semi-monocoque cross section sketched in the figure has three concentrated areasA, two panels with thickness t and one panel with thickness2t. Compute, with respect to the reference system sketched in the figure, thex coordinate of the shear center. (Unit for result: mm) Data a = 1 m A = 4 cm 2 E = 7 × 104 MPa ν = 0.3 Answer Exercise 3 Consider the thin beam model sketched in the figure, and loaded by the two forcesF. All the beams have the same cross-section. Compute the rotationθ of the point where the beam of lengthb is joined to the two beams of lengtha. Neglect shear deformability. (Unit for result: rad) Data a = 1 m b = 2 m c = 3 m EIxx = EIyy = 12 × 1014 N mm 2 EA = 6 × 1010 N GJ = 7 × 1014 N mm 2 K = 1 × 106 N/mm F = 10000 N Answer Exercise 4 Consider the simply supported…