Abstract
Normal modes of thin-walled axisymmetric shell structures are characterized by (1) overall body and (2) shell breathing families. By utilization of “body” deformation trial vectors, the two modal families are readily identified and separated. Local non-symmetrical structural features and/or imperfections cause body and breathing modes to mix (weak coupling) to form “fragmented” body mode clusters. Employment of singular value decomposition of experimental body mode cluster kinetic energies is found to consolidate the “fragments” back to ideally axisymmetric system body modes.
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Acknowledgements
The Modified Guyan Reduction concept was strongly influenced by conversations, during the mid 1980’s, with Robert T. Lahey, who had previously developed and applied a load patch procedure at Lockheed Aircraft Company. Dr. Sheldon Rubin, formerly with The Aerospace Corporation, studied weak coupling in launch vehicle structures over many years since the mid 1970’s. Rubin’s personal notes, under the same title as this paper, followed a different line of thought focusing on launch vehicle flight data based on sparsely allocated instrumentation. It is unfortunate that both Lahey’s and Rubin’s key contributions in model order reduction and mode consolidation, respectively, have not been published in the open literature.
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© 2019 The Society for Experimental Mechanics, Inc.
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Coppolino, R.N. (2019). Consolidation of Weakly Coupled Experimental System Modes. In: Barthorpe, R. (eds) Model Validation and Uncertainty Quantification, Volume 3. Conference Proceedings of the Society for Experimental Mechanics Series. Springer, Cham. https://doi.org/10.1007/978-3-319-74793-4_16
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DOI: https://doi.org/10.1007/978-3-319-74793-4_16
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