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Course of Spacecraft Structures Written test, March 3rd, 2017 Exercise 1 Consider the beam section in the gure. The panels have thickness t, and the lumped area of all the stringers is equal to A (note, the contribution of the panels is already included). The internal shear force is T . By making use of the semi-monocoque scheme, determine: the internal shear ows and the shear stresses acting on the panels. a a a T Data A = 250 mm 2 a = 300 mm t = 1.2 mm T = 5000 N Exercise 2 Consider the four-truss structure in the gure here below. All the trusses have a square section of dimen- sion a and are made of an homogeneous, isotropic material of modulus E. l1 P l1 l2 Data l1 = 1000 mm l2 = 1000 √ 3 mm a = 40 mm E = 72000 MPa P = 10 kN By adopting a displacement-based approach: • derive the discrete set of equilibrium equations (the solution of the equations is not required) • illustrate the procedure for evaluating the axial forces in the four truss elements • illustrate the procedure for evaluating the reaction forces Question 1 The beam in the gure has constant section properties, and is subjected to a generic transverse force per unit length q = q(x). One end is xed and the other end is hinged. By adopting a Timoshenko beam model, derive the equilibrium equations and the relevant boundary conditions in terms of generalized displacement components. q=q(x) EJ, GA 1