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A variable-complexity design strategy with combined aerodynamic and structural optimization procedures is presented for the high speed civil transport design (HSCT). Variable-complexity analysis methods are used to reduce the computational expense. A finite element-model based structural optimization procedure with flexible loads is implemented to evaluate the wing bending material weight. Static aeroelastic effects, evaluated through the comparison of rigid and flexible wing models, are found to be small in the HSCT design. The results of structural optimization are compared with two quasi-empirical weight equations. Good correlation is obtained between the structural optimization and one of the weight equations. Based on this comparison, an interlacing procedure is developed to combine both the simple weight equations and structural optimization in the HSCT design optimization, at modest computational cost. HSCT designs based on the interlacing procedure reveal that the aerodynamic optimizer may take advantage of weaknesses in weight equation. However, the optimizer may be unable to escape the local minimum due to the noisy of aerodynamic response and the lack of derivative information for the interlacing procedure. / Ph. D.

A method is presented for calculating the shape sensitivity of a wing aeroelastic response with respect to changes in geometric shape. Yates’ modified strip method is used in conjunction with Giles' equivalent plate analysis to predict the flutter speed, frequency, and reduced frequency of the wing. Three methods are used to calculate the sensitivity of the eigenvalue. The first method is purely a finite difference calculation of the eigenvalue derivative directly from the solution of the flutter problem corresponding to the two different values of the shape parameters. The second method uses an analytic expression for the eigenvalue sensitivities of a general complex matrix, where the derivatives of the aerodynamic, mass, and stiffness matrices are computed using a finite difference approximation. The third method also uses an analytic expression for the eigenvalue sensitivities but the aerodynamic matrix is computed analytically. All three methods are found to be in good agreement with each other. The sensitivities of the eigenvalues were used to predict flutter speed, frequency , and reduced frequency. These approximations were found to be in good agreement with those obtained using a complete reanalysis. However, it is recommended that higher order terms be used in the calculations in order to assure greater accuracy. / Master of Science / incomplete_metadata

Performance of inflatable wings was investigated through laboratory, wind tunnel and flight-testing. Three airfoils were investigated, an inflatable-rigidazable wing, an inflatable polyurethane wing and a fabric wing restraint with a polyurethane bladder. The inflatable wings developed and used within this research had a unique outer airfoil profile. The airfoil surface consisted of a series of chord-wise \bumps.andamp;quot; The effect of the bumps or \surface perturbationsandamp;quot; on the performance of the wings was of concern and was investigated through smoke-wire flow visualization. Aerodynamic measurements and predictions were made to determine the performance of the wings at varying chord based Reynolds Numbers and angles of attack. The inflatable baffes were found to introduce turbulence into the free-stream boundary layer, which delayed separation and improved performance. Another area of concern was aeroelasticity. The wings contain no solid structural members and thus rely exclusively on inflation pressure for stiffness. Inflation pressure was varied below the design pressure in order to examine the effect on wingtip twist and bending. This lead to investigations into wing deformation due to aerodynamic loading and an investigation of wing flutter. Photogrammetry and laser displacement sensors were used to determine the wing deflections. The inflatable wings exhibited wash-in deformation behavior. Alternately, as the wings do not contain structural members, the relationship between stiffness and inflation pressure was exploited to actively manipulate wing through wing warping. Several warping techniques were developed and employed within this re-search. The goal was to actively influence the shape of the inflatable wings to affect the flight dynamics of the vehicle employing them. Researchers have developed inflatable beam theory and models to analyze torsion and bending of inflatable beams and other inflatable structures. This research was used to model the inflatable wings to predict the performance of the inflatable wings during flight. Design elements of inflatable wings incorporated on the UAVs used within this research are also discussed. Finally, damage resistance of the inflatable wings is shown from results of flight tests.

This dissertation deals with the instability, known as flutter, of the lifting and control surfaces of aircraft of advanced design at high altitudes and speeds. A simple model is used to represent the aerodynamics for flutter analysis of a two-degree-of-freedom airfoil system. Flutter solutions of this airfoil system are shown to be algebraically homomorphic in that solutions about different elastic axes can be found by mapping them to those about the mid-chord. Algebraic expressions for the flutter speed and frequency are thus obtained. For the prediction of flutter of a wing at transonic speeds, an accurate and efficient computer code is developed. The unique features of this code are the capability of accepting a steady mean flow regardless of its origin, a time dependent perturbation boundary condition for describing wing deformations on the mean surface, and a locally applied three-dimensional far-field boundary condition for minimizing wave reflections from numerical boundaries. Results for various test cases obtained using this code show good agreement with the experiments and other theories.

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 1982. / Microfiche copy available in Archives and Barker. / Includes bibliographical references. / by Paul Michael Stremel. / M.S.

Thesis. 1977. M.S.--Massachusetts Institute of Technology. Dept. of Aeronautics and Astronautics. / This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND AERONAUTICS. / Includes bibliographical references. / M.S.

An inverted wing with various endplate configurations was investigated at two different angles of incidence. A moving ground was designed and constructed for use in the UNSW T1 wind tunnel. The test cases were investigated in ground effect using the moving ground. Measurements and observations were obtained using laser sheet flow visualisation and laser doppler anemometry. Computational fluid dynamics models of the test cases were run to gain further understanding of the flow field generated when using inverted wings with endplates. The computational fluid dynamics models correlated well to the experimental results.

<p>I examensarbetet analyseras läromedlet Wings (2003, 2005) ur ett genusperspektiv. De frågeställningar som ligger till grund för undersökningen är hur många gånger kvinnor/flickor och män/pojkar förekommer i texter och övningar, vem som har en aktiv respektive passiv roll, samt vilka yrken, handlingar och attribut som är kopplade till personerna.</p><p>Läromedlet Wings för år 7-9 har gåtts igenom och varje gång texter eller övningar har handlat om kvinnor/flickor och/eller män/pojkar har detta antecknats. Den person som har en framträdande roll, en aktiv roll, i en text eller övning har benämnts som ”huvudroll” i undersökningen. För ”huvudrollerna” har antecknats vilka yrken de har eller hur de presenteras för läsaren. Handlingar och attribut som är kopplade till ”huvudrollerna” har även antecknats. En analys görs också av foton på ”huvudrollerna” Kerrie och David och deras familj, släkt och vänner som finns i Base Book 7 (2003).</p><p>Undersökningen visar att Wings i stort förmedlar ett sunt genusperspektiv, där kvinnor/flickor och män/pojkar får lika stort utrymme och där både kvinnor/flickor och män/pojkar presenteras i sammanhang som visar på könens lika möjligheter. Samtidigt finns skildringar som förmedlar traditionella könsroller och negativa förväntningar på kvinnor/flickor och män/pojkar. Examensarbetet visar på vilka styrkor och svagheter läromedlet har ur ett genusperspektiv, samt hur man som lärare kan använda dessa i arbetet kring genus med eleverna.</p>

Thesis (M.S.)--University of Montana, 2006. / Title from PDF t.p. (viewed on July 2, 2007). Includes bibliographical references.