Experimental investigation of the structural scattering due to impedance discontinuities on a cylindrical shell

Ryan J. Glotzbecker, Stephen A. Hambric, Martin L. Pollack

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

Abstract

Experimental, numerical, and analytical work has shown that the response of a shell to a distributed force wave possesses unique characteristics which are dependent on the nature of structure attached to the shell. Specific characteristics which influence the response are the distribution of the discontinuities around the circumference (periodic/a-periodic), the impedance of the discontinuities relative to that of the shell, and the type of impedance (mass or stiffness). An experimental investigation into the harmonic scattering behavior of a shell due to mass discontinuities is presented in this paper. Knowledge of the key structural characteristics which influence scattering and their behavior will allow for a diagnostic tool when assessing the structural response of more complex cylindrical structures. Changes in structural response on a mode number basis as a result of the change in mass discontinuities are explored. Spatial Fourier analysis of both the input force and output response is used to provide a measure of the structural response matrix on a mode-by-mode basis. A distributed input force is simulated by applying forces around the circumference of the shell, then subsequently weighting the phase and amplitude of the measured transfer function according to the input force wave desired. This technique was applied to a shell in its unmodified condition, with periodic masses attached, and with a-periodic masses attached. Test results indicate that some harmonic scattering is present in the clean structure (no attached mass), likely due to non-ideal boundary conditions and the weld seam of the pipe used. Test results for the structure with periodically distributed masses indicate that response harmonics equal to the sum of input the harmonic number and an integer multiple of the number of discontinuities were excited. The structure with a-periodically distributed masses appears to scatter energy from the force harmonic into all response harmonics.

Original languageEnglish (US)
Title of host publicationAmerican Society of Mechanical Engineers, Noise Control and Acoustics Division (Publication) NCA
Pages263-269
Number of pages7
DOIs
StatePublished - Dec 1 2005
Event2005 ASME International Mechanical Engineering Congress and Exposition, IMECE 2005 - Orlando, FL, United States
Duration: Nov 5 2005Nov 11 2005

Publication series

NameAmerican Society of Mechanical Engineers, Noise Control and Acoustics Division (Publication) NCA
Volume32 NCA

Other

Other2005 ASME International Mechanical Engineering Congress and Exposition, IMECE 2005
CountryUnited States
CityOrlando, FL
Period11/5/0511/11/05

Fingerprint

cylindrical shells
discontinuity
impedance
Scattering
scattering
harmonics
Fourier analysis
Transfer functions
circumferences
Welds
Pipe
Stiffness
Boundary conditions
transfer functions
integers
stiffness
boundary conditions
output
matrices

All Science Journal Classification (ASJC) codes

  • Mechanical Engineering
  • Acoustics and Ultrasonics

Cite this

Glotzbecker, R. J., Hambric, S. A., & Pollack, M. L. (2005). Experimental investigation of the structural scattering due to impedance discontinuities on a cylindrical shell. In American Society of Mechanical Engineers, Noise Control and Acoustics Division (Publication) NCA (pp. 263-269). (American Society of Mechanical Engineers, Noise Control and Acoustics Division (Publication) NCA; Vol. 32 NCA). https://doi.org/10.1115/IMECE2005-79724
Glotzbecker, Ryan J. ; Hambric, Stephen A. ; Pollack, Martin L. / Experimental investigation of the structural scattering due to impedance discontinuities on a cylindrical shell. American Society of Mechanical Engineers, Noise Control and Acoustics Division (Publication) NCA. 2005. pp. 263-269 (American Society of Mechanical Engineers, Noise Control and Acoustics Division (Publication) NCA).
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Glotzbecker, RJ, Hambric, SA & Pollack, ML 2005, Experimental investigation of the structural scattering due to impedance discontinuities on a cylindrical shell. in American Society of Mechanical Engineers, Noise Control and Acoustics Division (Publication) NCA. American Society of Mechanical Engineers, Noise Control and Acoustics Division (Publication) NCA, vol. 32 NCA, pp. 263-269, 2005 ASME International Mechanical Engineering Congress and Exposition, IMECE 2005, Orlando, FL, United States, 11/5/05. https://doi.org/10.1115/IMECE2005-79724

Experimental investigation of the structural scattering due to impedance discontinuities on a cylindrical shell. / Glotzbecker, Ryan J.; Hambric, Stephen A.; Pollack, Martin L.

American Society of Mechanical Engineers, Noise Control and Acoustics Division (Publication) NCA. 2005. p. 263-269 (American Society of Mechanical Engineers, Noise Control and Acoustics Division (Publication) NCA; Vol. 32 NCA).

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

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Glotzbecker RJ, Hambric SA, Pollack ML. Experimental investigation of the structural scattering due to impedance discontinuities on a cylindrical shell. In American Society of Mechanical Engineers, Noise Control and Acoustics Division (Publication) NCA. 2005. p. 263-269. (American Society of Mechanical Engineers, Noise Control and Acoustics Division (Publication) NCA). https://doi.org/10.1115/IMECE2005-79724