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The main object of this thesis is to give a introductory study of the longitudinal motion of an aircraft, including some effects of nonuniform motion. Because this subject is connected with practical problems of importance in the domain of applied aerodynamics and control, a great effort has been given to setting up the physics of unsteady aerodynamics and its effects on the aircraft longitudinal modes. Numerical examples are given for both the two-dimensional and three-dimensional rigid wing, subsonic case. In this research, from the unsteady aerodynamic theory, through the frequency response calculation, system identification and the augmentation of the aircraft dynamic system, a carefully derived theory and a computer algorithm have been presented and used. It is our main purpose that a suitable unsteady aerodynamic transfer function be obtained and be coupled to the aircraft quasi-steady dynamic system. A new modified model which includes the unsteady aerodynamic effects has been constructed and been compared with the conventional model and the differences between them have been discussed. / Master of Science

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 1981. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND AERO / Bibliography: p. 131-132. / by Louis Howard Knotts. / M.S.

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Thesis (DTech (Mechanical Engineering))--Cape Peninsula University of Technology, 2015. / This dissertation addresses the development and the testing of a simulation tool to be used to predict the behaviour of smart material/structures. Along with the development of the simulation tool, a new form of the model describing the behaviour of shape-memory alloy was developed and implemented. The proposed model was developed based on the existing cosine model, conventionally used in literature, but it uses hyperbolic tangent functions. The hyperbolic tangent function was chosen so as to allow the simulation of any range of temperatures. Experiments were performed to obtain the parameters to be used in the simulation and to validate the numerical results. Two different simulations were performed: a one dimensional FEA analysis with a two dimensional orientation (NiTi SMA wire simulation) and a three dimensional FEA analysis (NiTi SMA plate) [Msomi and Oliver, 2015]. Alongside the FEA analysis, two experiments were performed with the purpose of obtaining the material parameters to be used in FEA analysis and to compare the FEA results to the experimental results. / Airbus Company

The objective of this research is to investigate the techniques and payoffs of integrated aircraft design. Lifting line theory and beam theory are used for the analysis of the aerodynamics and the structures of a composite sailplane wing. The wing is described by 33 - 34 design variables which involve the planform geometry, the twist distribution, and thicknesses of the spar caps, spar webs, and the skin at various stations along the wing. The wing design must satisfy 30 â 31 aeroelastic, structural, aerodynamic, and performance constraints. Two design procedures are investigated. The first, referred to as the iterative, sequential procedure, involves optimizing the aerodynamic design for maximum average cross-country speed at E1 constant structural weight, and then optimizing the the structural design of the resulting wing geometry for minimum weight. This value is then used in another aerodynamic optimization, and the process continues iteratively until the weight converges. The other procedure, the integrated one, simultaneously optimizes the aerodynamic and the structural design variables for either maximum average cross-country speed or minimum weight. The integrated procedure was able to improve the value of the objective function obtained by the iterative procedure in all cases. This shows The objective of this research is to investigate the techniques and payoffs of integrated aircraft design. Lifting line theory and beam theory are used for the analysis of the aerodynamics and the structures of a composite sailplane wing. The wing is described by 33 - 34 design variables which involve the planform geometry, the twist distribution, and thicknesses of the spar caps, spar webs, and the skin at various stations along the wing. The wing design must satisfy 30 â 31 aeroelastic, structural, aerodynamic, and performance constraints. Two design procedures are investigated. The first, referred to as the iterative, sequential procedure, involves optimizing the aerodynamic design for maximum average cross-country speed at E1 constant structural weight, and then optimizing the the structural design of the resulting wing geometry for minimum weight. This value is then used in another aerodynamic optimization, and the process continues iteratively until the weight converges. The other procedure, the integrated one, simultaneously optimizes the aerodynamic and the structural design variables for either maximum average cross-country speed or minimum weight. The integrated procedure was able to improve the value of the objective function obtained by the iterative procedure in all cases. This shows that definite benefits can be gained from taking advantage of aerodynamic/structural interactions during the design process. / Master of Science