### ASA 129th Meeting - Washington, DC - 1995 May 30 .. Jun 06

## 2aSP6. A wavelet method for estimating frequency-dependent damping in
structures.

**Gary R. Wilson
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*Appl. Res. Labs., Univ. of Texas, P.O. Box 8029, Austin, TX 78713-8029
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Estimation of damping from the measurement of the vibrations or acoustic
radiation of structures provides some insight into energy storage and
dissipation mechanisms in the structure. Because damping is typically
proportional to frequency, a method of estimating damping that scales with
frequency is suggested. A wavelet approach has been taken to exploit the
natural scaling properties of wavelets to estimate frequency-dependent damping.
A wavelet transform, the damped complex exponential (DCE) transform, has been
designed specifically for measuring damping [R. D. Priebe and G. R. Wilson,
IEEE ICASSP 3, 205--208 (1994)]. This transform has been applied to stimulate
impulse response frequencies to determine its accuracy and sensitivity to
mismatch between the assumed damping/frequency ratio used by the wavelet
transform and the actual damping/frequency ratio of the impulse response. It
has also been applied to the measured impulse response of a fluid loaded thin
elastic shell. Results of these measurements show reasonable agreement with
theoretical predictions of damping.