Full metadata
Title
Reduced order modeling with variable spatial fidelity for the linear and nonlinear dynamics of multi-bay structures
Description
This investigation develops small-size reduced order models (ROMs) that provide an accurate prediction of the response of only part of a structure, referred to as component-centric ROMs. Four strategies to construct such ROMs are presented, the first two of which are based on the Craig-Bampton Method and start with a set of modes for the component of interest (the β component). The response in the rest of the structure (the α component) induced by these modes is then determined and optimally represented by applying a Proper Orthogonal Decomposition strategy using Singular Value Decomposition. These first two methods are effectively basis reductions techniques of the CB basis. An approach based on the “Global - Local” Method generates the “global” modes by “averaging” the mass property over α and β comp., respectively (to extract a “coarse” model of α and β) and the “local” modes orthogonal to the “global” modes to add back necessary “information” for β. The last approach adopts as basis for the entire structure its linear modes which are dominant in the β component response. Then, the contributions of other modes in this part of the structure are approximated in terms of those of the dominant modes with close natural frequencies and similar mode shapes in the β component. In this manner, the non-dominant modal contributions are “lumped” onto the dominant ones, to reduce the number of modes for a prescribed accuracy. The four approaches are critically assessed on the structural finite element model of a 9-bay panel with the modal lumping-based method leading to the smallest sized ROMs. Therefore, it is extended to the nonlinear geometric situation and first recast as a rotation of the modal basis to achieve unobservable modes. In the linear case, these modes completely disappear from the formulation owing to orthogonality. In the nonlinear case, however, the generalized coordinates of these modes are still present in the nonlinear terms of the observable modes. A closure-type algorithm is then proposed to eliminate the unobserved generalized coordinates. This approach, its accuracy and computational savings, was demonstrated on a simple beam model and the 9-bay panel model.
Date Created
2017
Contributors
- Wang, Yuting (Author)
- Mignolet, Marc P (Thesis advisor)
- Jiang, Hanqing (Committee member)
- Liu, Yongming (Committee member)
- Oswald, Jay (Committee member)
- Rajan, Subramaniam D. (Committee member)
- Spottswood, Stephen M (Committee member)
- Arizona State University (Publisher)
Topical Subject
Resource Type
Extent
xxii, 138 pages : illustrations (some color)
Language
eng
Copyright Statement
In Copyright
Primary Member of
Peer-reviewed
No
Open Access
No
Handle
https://hdl.handle.net/2286/R.I.42064
Statement of Responsibility
by Yuting Wang
Description Source
Viewed on April 24, 2017
Level of coding
full
Note
thesis
Partial requirement for: Ph.D., Arizona State University, 2017
bibliography
Includes bibliographical references (pages 134-138)
Field of study: Mechanical engineering
System Created
- 2017-04-01 08:01:25
System Modified
- 2021-08-30 01:19:44
- 3 years 2 months ago
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