Measurement of Mode Shape By Using A Scanning Laser Doppler Vibrometer

스캐닝 레이저 도플러 진동계를 이용한 모드 해석

Gang, Min-Sik

  • Published : 2000.10.01


When spatially dense velocity distribution is measured by a scanning laser Doppler vibrometer, the Fourier transform method provides the real and imaginary parts of the mode shapes in the form of a polynomial. However the Fourier transform method is often impractical because the independent decomposition property of cosine and sine components into real and imaginary parts, respectively, does not hold due to the leakage problem which commonly occurs in the Fourier transform of harmonic signals. To deal with this problem, a Hilbert transform method is newly proposed in this article. The proposed method is free from the leakage problem and relatively robust to the scanning error. A simulation example is provided to verify the effectiveness of this method.


Mode Shape;Scanning Laser Doppler Vibrometer;Fourier Transform;Hilbert Transform;Envelope;Instantaneous Phase


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