Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 1996. / Vita. / Includes bibliographical references (leaves 84-86). / by Joe P. Grisham. / M.S.

Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 1983. / MICROFICHE COPY AVAILBLE IN ARCHIVES AND AERO. / Includes bibliographical references. / by Jean-Jacques E. Slotine. / Ph.D.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 1992. / Includes bibliographical references (leaves 138-140). / by Laureano Alberto Cangahuala. / Ph.D.

"February 2001." / Includes bibliographical references (p. 167-168). / Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2001. / The goal of this research is to measure the aerodynamic performance of a film-cooled turbine stage and to quantify the loss caused by film-cooling. A secondary goal of the research is to provide a detailed breakdown of the losses associated with film-cooling for the turbine stage being tested. The experimental work was carried out at the MIT Blowdown Turbine Facility using a highly loaded turbine stage. The Blowdown Turbine Facility is a short duration test facility capable of testing turbine stages under fully scaled conditions for a test duration of 0.5 seconds. The facility was modified to enable the measurement of the turbine mass flow and shaft torque. These newly developed measurement techniques, along with previously developed total pressure and temperature instruments, have enabled the measure- ment of the stage isentropic efficiency. A highly loaded turbine stage (without film-cooling) was designed, fabricated, and tested using the newly developed measurement techniques. The turbine stage was then modified to incorporate vane, blade and rotor casing coolant manifolds using precision electrical discharge machining. The film-cooling hole geometry was created using a laser drilling process to produce the required 43,000 cooling holes. The film-cooled stage was then tested over a range of operating conditions (pressure ratios and corrected speeds) and over a range of coolant-to-mainstream mass flow and temperature ratios. / (cont.) The loss due to film-cooling is defined as the difference in performance between the film-cooled turbine and an ideal turbine with the same velocity triangles and airfoil Mach number distributions. However, there is no uncooled turbine geometry that will produce the same flow conditions as the film-cooled turbine stage, and consequently, there is no experimental baseline that can be tested to determine the loss due to film- cooling. A meanline velocity triangle model of the turbine stage was developed using published correlations and loss models to estimate the performance of this ideal stage. The model was calibrated against the baseline test results without coolant and it was then used to estimate the loss due to film-cooling. The estimated loss due to film-cooling was 3.0% at the design point, which corresponds to 0.3% per percent of coolant. The estimated repeatability (U95) for the efficiency measurement of the uncooled tur- bine geometry is ± 0.14%. Based on this measurement repeatability, the net effect of a design change can be determined with an uncertainty of just ± 0.1% if four measurements are repeated for each design configuration. The estimated measurement uncertainty for the film-cooled stage efficiency is 0.55% and for back-to-back measurements the uncertainty is 0.45%. / by Rory Keogh. / Ph.D.

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2004. / Includes bibliographical references (p. 103-105). / The Terrestrial Planet Finder (TPF) mission, to be launched in 2014 as a part of NASA's Origins Program, will search for Earth-like planets orbiting other stars. One main concept under study is a structurally connected interferometer. Integrated modeling of all aspects of the flight system is necessary to ensure that the stringent dynamic stability requirements imposed by the mission are met. The MIT Space Systems Laboratory has developed a suite of analysis tools known as DOCS (Disturbances Optics Controls Structures) that provides a MATLAB environment for managing integrated models and performing analysis and design optimization. DOCS provides a framework for identifying critical subsystem design parameters and efficiently computing system performance as a function of subsystem design. Additionally, the gradients of the performance outputs with respect to design variables can be analytically computed and used for automated exploration and optimization of the design space. The TPF integrated model consists of a structural finite element model, optical performance model, reaction wheel isolation stage, and attitude/optical control systems. The integrated model is expandable and upgradeable due to the modularity of the state-space subsystem models. Optical performance under reaction wheel disturbances is computed, and the effects of changing design parameters are explored. The results identify redesign options that meet performance requirements with improved margins, reduced cost and minimized risk. / by David M. LoBosco. / S.M.

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2005. / Includes bibliographical references (p. 181-195). / The modeling and design of MEMS-scale piezoelectric-based vibration energy harvesters (MPVEH) are presented. The work is motivated by the need for pervasive and limitless power for wireless sensor nodes that have application in structural health monitoring, homeland security, and infrastructure monitoring. A review of prior milli- to micro-scale harvesters is provided. Common ambient low-level vibration sources are characterized experimentally. Coupled with a dissipative system model and a mechanical damping investigation, a new scale-dependent operating frequency selection scheme is presented. Coupled electromechanical structural models are developed, based on the linear piezoelectric constitutive description, to predict uni-morph and bi-morph cantilever beam harvester performance. Piezoelectric coupling non-intuitively cancels from the power prediction under power-optimal operating conditions, although the voltage and current are still dependent on this property. Piezoelectric material selection and mode of operation ([3-1] vs. [3-3]) therefore have little effect on the maximum power extracted. The model is verified for resonance and off-resonance operation by comparison to new experimental results for a macro-scale harvester. Excellent correlation is obtained away from resonances in the small-strain linear piezoelectric regime. The model consistently underpredicts the response at resonances due to the known non-linear piezoelectric constitutive response (higher strain regime). Applying the model, an optimized single prototype bi-morph MPVEH is designed concurrently with a microfabrication scheme. / (cont.) A low-level (2.5 m/s²), low-frequency (150 Hz) vibration source is targeted for anti-resonance operation, and a power density of 313 [mu]W/cm³ and peak-to-peak voltage of 0.38 V are predicted per harvester. Methodologies for the scalar analysis and optimization of uni-morph and bi-morph harvesters are developed, as well as a scheme for chip-level assembly of harvester clusters to meet different node power requirements. / by Noël Eduard du Toit. / S.M.

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 1991. / Title as it appears in the June, 1991 M.I.T. Graduate List: Robust control of systems with parametric uncertainty. / Includes bibliographical references (p. 156-158). / by Carl S. Resnik. / M.S.

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 1991. / Includes bibliographical references (leaves 50-51). / by Eric J. Gaidos. / M.S.

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 1964. / MICROFICHE COPY AVAILABLE IN AERO. / Includes bibliographical references (leaves 115-119). / by Derek Howard Baker, James Weatherspoon Harrill. / M.S.

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 1995. / Includes bibliographical references (p. 159-167). / by Alexander C. Hou. / M.S.