Experimental Demonstration of a Tunable Acoustoelastic System

Deborah Fowler, Garrett Lopp, Dhiraj Bansal, Ryan Schultz, Matthew Brake, Micah Shepherd

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

Acoustoelastic coupling occurs when a hollow structure’s in-vacuo mode aligns with an acoustic mode of the internal cavity. The impact of this coupling on the total dynamic response of the structure can be quite severe depending on the similarity of the modal frequencies and shapes. Typically, acoustoelastic coupling is not a design feature, but rather an unfortunate result that must be remedied as modal tests are often used to correlate or validate finite element models of the uncoupled structure. Here, however, a test structure is intentionally designed such that multiple structural and acoustic modes are well-aligned, resulting in a coupled system that allows for an experimental investigation. Coupling in the system is first identified using a measure termed the magnification factor and the structural-acoustic interaction for a target mode is then measured. Modifications to the system demonstrate the dependency of the coupling with respect to changes in the mode shape and frequency proximity. This includes an investigation of several practical techniques used to decouple the system by altering the internal acoustic cavity, as well as the structure itself. Furthermore, acoustic absorption material effectively decoupled the structure while structural modifications, in their current form, proved unsuccessful. The most effective acoustic absorption method consisted of randomly distributing typical household paper towels in the acoustic cavity; a method that introduces negligible mass to the structural system with the additional advantages of being inexpensive and readily available.

Original languageEnglish (US)
Title of host publicationRotating Machinery, Vibro-Acoustics and Laser Vibrometry, Proceedings of the 36th IMAC, A Conference and Exposition on Structural Dynamics 2018
EditorsDario Di Maio
PublisherSpringer New York LLC
Pages179-189
Number of pages11
ISBN (Print)9783319746920
DOIs
StatePublished - Jan 1 2019
Event36th IMAC, A Conference and Exposition on Structural Dynamics, 2018 - Orlando, United States
Duration: Feb 12 2018Feb 15 2018

Publication series

NameConference Proceedings of the Society for Experimental Mechanics Series
ISSN (Print)2191-5644
ISSN (Electronic)2191-5652

Other

Other36th IMAC, A Conference and Exposition on Structural Dynamics, 2018
CountryUnited States
CityOrlando
Period2/12/182/15/18

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All Science Journal Classification (ASJC) codes

  • Engineering(all)
  • Computational Mechanics
  • Mechanical Engineering

Cite this

Fowler, D., Lopp, G., Bansal, D., Schultz, R., Brake, M., & Shepherd, M. (2019). Experimental Demonstration of a Tunable Acoustoelastic System. In D. Di Maio (Ed.), Rotating Machinery, Vibro-Acoustics and Laser Vibrometry, Proceedings of the 36th IMAC, A Conference and Exposition on Structural Dynamics 2018 (pp. 179-189). (Conference Proceedings of the Society for Experimental Mechanics Series). Springer New York LLC. https://doi.org/10.1007/978-3-319-74693-7_17