Estimation of plate material properties by means of a complex wavenumber fit using Hankel's functions and the image source method

• Published in: Journal of sound and vibration 2017-03, Vol.390, p.257-271
• Main Authors: Roozen, N.B., Leclère, Q., Ege, K., Gerges, Y.
• Format: Article
• Language: English
• Subjects: Anisotropy; Damping; Determination of material properties; Engineering Sciences; Image source method; Isotropic material; Material properties; Mathematical analysis; Measurement based; Mechanical properties; Mechanics; Physics; Plate material; Plates (structural members); Point excited plate; Reflectance; Reflected waves; Stiffness; Studies; Vibration analysis; Vibrations; Wave fitting; Wavelengths
• ISSN: 0022-460X; 1095-8568
• DOI: 10.1016/j.jsv.2016.11.037

This paper presents a new wave fitting approach to estimate the frequency dependent material properties of thin isotropic plate structures from an experimentally obtained vibrational field, exciting the plate at a single point. The method projects the measurement data on to an analytical image source model, in which Hankel's functions are used for a description of the wave fields emanating from the point of excitation, including the reflected wave fields from the edges of the finite plate. By minimizing the error between the projected field and the measured field, varying the complex wave number and the source strengths of the image sources, an optimum fit is searched for. Thus the source strengths of the image sources do not need to be determined theoretically, but are estimated from the fit on to the experimental data instead (thus avoiding difficulties in theoretically assessing the reflection coefficient of the edges of the plate). The approach uses a complex wavenumber fit, enabling the determination of the dynamic stiffness of the plate structure and its damping properties as function of frequency. The method is especially suited for plates with a sufficient amount of damping, excited at high frequencies. •Determination of material properties of thin plates from experimental vibrational fields.•Wave fitting approach projecting measurement data of plate vibrations on to an analytical image source model.•Bayesian regularization for the determination of the strengths of the image sources.