Comparison of modal analysis between laser vibrometry and NAH measurements
Document Type
Conference Proceeding
Publication Date
1-1-2012
Department
Department of Mechanical Engineering-Engineering Mechanics
Abstract
Noise and vibration has long been sought to be reduced in major industries: automotive, aerospace and marine to name a few. Products must be tested and pass certain levels of federally regulated standards before entering the market. Vibration measurements are commonly acquired using accelerometers; however limitations of this method create a need for alternative solutions. Two methods for non-contact vibration measurements are compared: Laser Vibrometry, which directly measures the surface velocity of the aluminum plate, and Nearfield Acoustic Holography (NAH), which measures sound pressure in the nearfield, and using Green's Functions, reconstructs the surface velocity at the plate. The surface velocity from each method is then used in modal analysis to determine the comparability of frequency, damping and mode shapes. Frequency and mode shapes are also compared to an FEA model. Laser Vibrometry is a proven, direct method for determining surface velocity and subsequently calculating modal analysis results. NAH is an effective method in locating noise sources, especially those that are not well separated spatially. Little work has been done in incorporating NAH into modal analysis.
Publication Title
Conference Proceedings of the Society for Experimental Mechanics Series
Recommended Citation
Potter, J.,
Van Karsen, C.,
Declerck, J. P.,
&
Sklanka, B.
(2012).
Comparison of modal analysis between laser vibrometry and NAH measurements.
Conference Proceedings of the Society for Experimental Mechanics Series,
5, 471-480.
http://doi.org/10.1007/978-1-4614-2425-3_45
Retrieved from: https://digitalcommons.mtu.edu/michigantech-p/4039