209 構造物から発生する衝撃音の原因箇所可視化に関する実験的検討

概要

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This report shows a method for visualization of impulsive sound source on solid structure. The authors have some experimental results of sound source localization on an operated faulty bearing by Near-field Acoustic Holography (NAH), in which the images of sound sources are on the ring of the bearing. Such results are reasonable because a ring structure can show mode vibration, however, it is preferable that a location of fault or impulsive sound source can be visualized. In this work, a simple beam was used as an impacted structure to clarify the detail of spatial distribution of propagated impulsive sound from a structure. The sound from the beam was measured by means of spatial distributed microphones immediately after the impact. Amplitudes and time lags were detected in each wave signal from the microphone, and imaginary 2-D distributions of them were constructed from several data. The reconstruction process in NAH was used to emphasize the impacted location, in which an enhancement of evanescent wave component is effective to emphasize a small variation on the distribution.
一般社団法人日本機械学会の論文
2003-06-04