The Application of the Optical Interferometer for Dynamical Analysis on Plates
Date Issued
2007
Date
2007
Author(s)
Chang, Shu-Hua
DOI
en-US
Abstract
Because of its non-contact and high-resolution characteristics, optical measurement has been one of the most important techniques of measurements. The interferometry structure has two types including a common path and a non-common path. In the architecture of non-common path, the reference beam and object beam spread in different optical paths. Therefore, the precise of measurement is easily influenced by the environment condition. However, both beams in the common path structure deliver in the same optical path. This way can get over the environmental factors in laboratory. The lateral shearing interferometer is the typical common path interferometry. This structure is not so sensitive to the external condition, which enables itself not to be limited in the optical laboratory in experiments.
One of the most interesting and useful applications of lateral shearographic interferometry is the detection and measurement of the vibration objects deformation. The lateral shearing interferometers combined with phase shifting for vibration analysis of plates can be presented perfectly. The one which should be mentioned is methods of measuring vibration. We adopt the time average and stroboscopic techniques.
This study attempts to discuss the lateral shearing interferometer approach in order to find out the location of maximum amplitude. And applying added mass loading and inner support methods can change the resonant modal and meanwhile reduce the acoustic radiation from square plates. The study includes the dynamical analysis of uniform plates, the theoretical consideration on vibration analysis and lateral shearing interferometer, and the laboratory demonstration on the acoustic-radiation reduction of plates by using lateral shearing interferometer approach.
Results of dynamical analysis on different plates obviously reveal lower modes such as (1, 1) and (1, 2) modes must respond to the most acoustic radiation from plates. This experiment proves that much more reduction of acoustic radiation from plates over greater frequency range can be reached when using a lateral shearing interferometer. The corresponding experimental results clearly show that the greater effectiveness on (1, 1) mode by 32.2dB reduction for glass polish finish plate refashioned by using mass loading.
Subjects
矩形平板
四邊固定
橫向剪切干涉術
rectangular plate
fix end
lateral shearing interferometer
Type
thesis
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