Spatial Nyquist fidelity method for structural models of opto-mechanical systems

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2007.

Bibliographic Details
Main Author: Howell, Deborah Jane, 1979-
Other Authors: Olivier L. de Weck and David W. Miller.
Format: Thesis
Language:eng
Published: Massachusetts Institute of Technology 2008
Subjects:
Online Access:http://hdl.handle.net/1721.1/42046
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author Howell, Deborah Jane, 1979-
author2 Olivier L. de Weck and David W. Miller.
author_facet Olivier L. de Weck and David W. Miller.
Howell, Deborah Jane, 1979-
author_sort Howell, Deborah Jane, 1979-
collection MIT
description Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2007.
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spelling mit-1721.1/420462019-04-11T02:51:11Z Spatial Nyquist fidelity method for structural models of opto-mechanical systems Howell, Deborah Jane, 1979- Olivier L. de Weck and David W. Miller. Massachusetts Institute of Technology. Dept. of Aeronautics and Astronautics. Massachusetts Institute of Technology. Dept. of Aeronautics and Astronautics. Aeronautics and Astronautics. Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2007. This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections. Includes bibliographical references (p. 189-196). As technology employed in complex multidisciplinary systems such as high performance telescope systems becomes ever more sophisticated, simulation is becoming more important during the initial design phases. The method of building these simulation models is often based on engineering experience with older, potentially dissimilar systems. A method is needed to measure the fidelity of simulation models so early design decisions are made based on appropriate modeling techniques. Previously, fidelity was a qualitative concept used to indicate a model's validity or accuracy. Here it is defined as the ability of a model to accurately predict chosen output figures of merit. In this thesis, a quantitative measure of fidelity, termed the Nyquist fidelity metric, is defined for commonly used structural model components. It expresses the ability of a finite element model to accurately predict structural eigenvalues based on the mesh size required by the spatial Nyquist criterion. The Nyquist fidelity method is developed which uses the fidelity metric to both assess the fidelity of existing complex models and to synthesize new multi-component models starting from architectural considerations such as geometric and material properties of the system. This method also estimates the error bound on the output figures of merit based on the fidelity levels and sensitivity analysis. The Nyquist fidelity method is applied to simple sample problems to first demonstrate the methodology and it is then applied to complex telescope models to show the accuracy and computational benefits of this method compared to current methods such as model reduction. The three high performance telescope case studies are the Modular Optical Space Telescope (MOST), the Thirty Meter Telescope, and the Stratospheric Observatory for Infrared Astronomy. (cont.) It is shown in the MOST example that the Nyquist fidelity method provides a 40% improvement in computational time while assuring less than 5% modal frequency error, and less than 2.2% error in the output figure of merit. by Deborah Jane Howell. Ph.D. 2008-09-02T17:54:08Z 2008-09-02T17:54:08Z 2007 2007 Thesis http://hdl.handle.net/1721.1/42046 228880193 eng M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission. http://dspace.mit.edu/handle/1721.1/7582 196 p. application/pdf Massachusetts Institute of Technology
spellingShingle Aeronautics and Astronautics.
Howell, Deborah Jane, 1979-
Spatial Nyquist fidelity method for structural models of opto-mechanical systems
title Spatial Nyquist fidelity method for structural models of opto-mechanical systems
title_full Spatial Nyquist fidelity method for structural models of opto-mechanical systems
title_fullStr Spatial Nyquist fidelity method for structural models of opto-mechanical systems
title_full_unstemmed Spatial Nyquist fidelity method for structural models of opto-mechanical systems
title_short Spatial Nyquist fidelity method for structural models of opto-mechanical systems
title_sort spatial nyquist fidelity method for structural models of opto mechanical systems
topic Aeronautics and Astronautics.
url http://hdl.handle.net/1721.1/42046
work_keys_str_mv AT howelldeborahjane1979 spatialnyquistfidelitymethodforstructuralmodelsofoptomechanicalsystems