IMT Institutional Repository: No conditions. Results ordered -Date Deposited. 2024-05-18T07:13:54ZEPrintshttp://eprints.imtlucca.it/images/logowhite.pnghttp://eprints.imtlucca.it/2015-03-27T11:14:59Z2015-03-27T12:54:14Zhttp://eprints.imtlucca.it/id/eprint/2651This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/26512015-03-27T11:14:59ZAero-Elastic Analysis of Stiffened Composite Wing StructureThe interaction of the Elastic, Inertia and Aerodynamic forces is a dynamic phenomena resulting in flutter. Dynamic Aero elasticity is critical for a high-speed subsonic class of AerialVehicles. In the presentwork, dynamic Aero-elastic analysis of the Unmanned Aerial Vehicles (UAVs) has been studied for a stiffened composite structure. The flutter speed and the corresponding flutter frequencies are computed using the Velocity-Damping (V -g) method. The V -g method is employed to estimate the flutter speed and flutter frequencies, for a high-speed subsonic composite wing structure, designed and developed at ADE. Also the improvement of the flutter frequencies over the existing metallic wing structure is discussed. The work can be further extended to develop an optimized composite structure with higher margins in flutter speeds.
Keywords: Aeroelasticity, Flutter, Velocity-damping methodPattabhi R. Budarapupattabhi.budarapu@imtlucca.itB. RammohanS. Vijay KumarD. Satish Babu R. Raghuatnhan2015-03-27T10:18:27Z2015-03-27T12:54:13Zhttp://eprints.imtlucca.it/id/eprint/2643This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/26432015-03-27T10:18:27ZDirectionality of sound radiation from rectangular panels Abstract In this paper, the directionality of sound radiated from a rectangular panel, attached with masses/springs, set in a baffle, is studied. The attachment of masses/springs is done based on the receptance method. The receptance method is used to generate new mode shapes and natural frequencies of the coupled system, in terms of the old mode shapes and natural frequencies. The Rayleigh integral is then used to compute the sound field. The point mass/spring locations are arbitrary, but chosen with the objective of attaining a unique directionality. The excitation frequency to a large degree decides the sound field variations. However, the size of the masses and the locations of the masses/springs do influence the new mode shapes and hence the sound field. The problem is more complex when the number of masses/springs are increased and/or their values are made different. The technique of receptance method is demonstrated through a steel plate with attached point masses in the first example. In the second and third examples, the present method is applied to estimate the sound field from a composite panel with attached springs and masses, respectively. The layup sequence of the composite panel considered in the examples corresponds to the multifunctional structure battery material system, used in the micro air vehicle (MAV) (Thomas and Qidwai, 2005). The demonstrated receptance method does give a reasonable estimate of the new modes. Pattabhi R. Budarapupattabhi.budarapu@imtlucca.itT.S.S. NarayanaB. RammohanTimon Rabczuk