DETERMINATION OF FREQUENCY RESPONSE FUNCTIONS FROM RESPONSE MEASUREMENTS—I. EXTRACTION OF POLES AND ZEROS FROM RESPONSE CEPSTRA

✍ Scribed by Y. Gao; R.B. Randall

• Publisher: Elsevier Science
• Year: 1996
• Tongue: English
• Weight: 654 KB
• Volume: 10
• Category: Article
• ISSN: 0888-3270
• DOI: 10.1006/mssp.1996.0022

✦ Synopsis

In the current investigation a procedure is proposed to extract poles and zeros of transfer functions from response vibrations. In this procedure use is made of the deconvolution properties of cepstral analysis, that is, in the cepstrum domain, source and path effects are not only additive but also separated into different quefrency regions. The source effect is excluded and the complex or differential cepstra of the path are curve-fitted to extract poles and zeros. The Levenberg-Marquardt and Ibrahim time domain methods are adapted for the curve-fitting purpose. In the Levenberg-Marquardt method path dominated complex or differential cepstra (after the source effect is removed) are curve-fitted to their corresponding analytical expressions, while in the Ibrahim time domain method differential cepstra are treated as free response data. The advantages and disadvantages of the two methods are compared. The validation of this procedure is demonstrated by using the response of a free-free beam to impact and double impact excitations.