Abstract
In 2010, Allen & Mayes proposed to estimate the fixed-interface modes of a structure by measuring the modes of the structure bolted to a fixture and then applying constraints to the fixture using the transmission simulator method. While the method proved useful, and has indeed been used in studies since that point, a few peculiarities were noted. First, in some cases the estimated fixed-base natural frequencies were observed to converge very slowly to the true values (in simulated experiments) as the number of constraints was increased. To formulate these constraints, prior studies used only the free-interface modes of the fixture or the measured modes of the assembly. This work extends that to consider other sets of constraints, showing improved results. Furthermore, in some prior studies it has been observed that there were errors of more than 10% in the natural frequencies even when the fixture motion was hundreds of times smaller than the motion of the structure of interest (and so it had presumably been removed). This work explores this phenomenon, seeking to use the strain energy in the fixture, to the extent that it can be estimated using a test-analysis model for the fixture, as a metric to predict frequency error. The proposed methods are explored by applying them to simulated measurements from a beam and from the NASA Space Launch System coupled to the Mobile Launcher.
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Notes
- 1.
https://www.nasa.gov/pdf/588413main_SLS_Fun_Facts.pdf, accessed October 2017.
References
Allen, M.S., Gindlin, H.M., Mayes, R.L.: Experimental modal substructuring to estimate fixed-base modes from tests on a flexible fixture. J. Sound Vib. 330, 4413–4428 (2011)
de Klerk, D., Rixen, D.J., Voormeeren, S.N.: General framework for dynamic substructuring: history, review, and classification of techniques. AIAA J. 46, 1169–1181 (2008)
Martinez, D.R., Carne, T.G., Gregory, D.L., Miller, A.K.: Combined experimental/analytical modeling using component mode synthesis, AIAA/ASME/ASCE/AHS structures, Structural Dynamics & Materials Conference, Palm Springs, CA, USA (1984)
Ewins, D.J.: Modal Testing: Theory, Practice and Application. Research Studies Press, Baldock (2000)
Corus, M., Balmes, E., Nicolas, O.: Using model reduction and data expansion techniques to improve SDM. Mech. Syst. Signal Process. 20, 1067–1089 (2006)
Allen, M.S., Mayes, R.L.: Comparison of FRF and modal methods for combining experimental and analytical substructures. In: 25th International Modal Analysis Conference (IMAC XXV), Orlando, Florida (2007)
Sjovall, P., Abrahamsson, T.: Substructure system identification from coupled system test data. Mech. Syst. Signal Process. 22, 15–33 (2008)
Allen, M.S., Mayes, R.L., Bergman, E.J.: Experimental modal substructuring to couple and uncouple substructures with flexible fixtures and multi-point connections. J. Sound Vib. 329, 4891–4906 (2010)
Mayes, R.L., Hunter, P.S., Simmermacher, T.W., Allen, M.S.: Combining experimental and analytical substructures with multiple connections. In: 26th International Modal Analysis Conference (IMAC XXVI), Orlando, Florida (2008)
de Klerk, D., Rixen, D.J.: Component transfer path analysis method with compensation for test bench dynamics. Mech. Syst. Signal Process. 24, 1693–1710 (2010)
Urgueira, A.P.V.: Dynamic analysis of coupled structures using experimental data, PhD Thesis, Imperial College of Science, Technology and Medicine, University of London, London (1989)
Imregun, M., Robb, D.A., Ewins, D.J.: Structural modification and coupling dynamic analysis using measured FRF data. In: 5th International Modal Analysis Conference (IMAC V), London, England (1987)
Carne, T.G., Dohrmann, C.R.: Improving experimental frequency response function matrices for admittance modeling. In: 24th International Modal Analysis Conference (IMAC XXIV), St. Louis, Missouri (2006)
Martinez, D.R., Miller, A.K., Carne, T.G.: Combined experimental and analytical modeling of shell/payload structures. In: The Joint ASCE/ASME Mechanics Conference, Albuquerque, NM (1985)
Mottershead, J.E., Kyprianou, A., Ouyang, H.: Structural modification. Part 1: rotational receptances. J. Sound Vib. 284, 249–265 (2005)
Kyprianou, A., Mottershead, J.E., Ouyang, H.: Structural modification. Part 2: assignment of natural frequencies and antiresonances by an added beam. J. Sound Vib. 284, 267–281 (2005)
de Klerk, D.: Dynamic response characterization of complex systems through operational identification and dynamic substructuring, PhD Thesis: Delft University of Technology (2009)
de Klerk, D., Rixen, D.J., Voormeeren, S.N., Pasteuning, F.: Solving the RDoF problem in experimental dynamic substructuring. In: 26th International Modal Analysis Conference (IMAC XXVI), Orlando, Florida (2008)
Napolitano, K., Yoder, N., Fixed base FRF using boundary measurements as references – analytical derivation. In: 30th International Modal Analysis Conference (IMAC XXX), Jacksonville, FL (2012)
Yoder, N., Napolitano, K.: Fixed base FRF using boundary measurements as references – experimental results. In: 30th International Modal Analysis Conference (IMAC XXX), Jacksonville, FL (2012)
Mayes, R.L., Arviso, M.: Design studies for the transmission simulator method of experimental dynamic substructuring, International Seminar on Modal Analysis (ISMA2010), Lueven, Belgium (2010)
Ginsberg, J.H.: Mechanical and Structural Vibrations, 1st edn. John Wiley and Sons, New York (2001)
Acknowledgements
This research is based on work that was originally supported by Sandia National Laboratories. Sandia National Laboratories is a multi-mission laboratory managed and operated by National Technology and Engineering Solutions of Sandia, LLC., a wholly owned subsidiary of Honeywell International, Inc., for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-NA-0003525. The authors also gratefully acknowledge the support of the National Aeronautics and Space Administration (NASA) and the helpful comments provided by members of the Loads and Dynamics Technical Discipline Team of the NASA Engineering & Safety Center (NESC).
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Allen, M.S., Mayes, R.L. (2018). Recent Advances to Estimation of Fixed-Interface Modal Models Using Dynamic Substructuring. In: Linderholt, A., Allen, M., Mayes, R., Rixen, D. (eds) Dynamics of Coupled Structures, Volume 4. Conference Proceedings of the Society for Experimental Mechanics Series. Springer, Cham. https://doi.org/10.1007/978-3-319-74654-8_13
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DOI: https://doi.org/10.1007/978-3-319-74654-8_13
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