MEASUREMENT OF BROAD-BAND INTRINSIC ULTRASONIC-ATTENUATION AND DISPERSION IN SOLIDS WITH LASER TECHNIQUES

In this paper, a methodology is presented for measuring the intrinsic ultrasonic attenuation and dispersion on a broad frequency band (nearly 6 octaves) in polymers (PVC, PE, PMMA, PC, PP, POM, nylon) using laser ultrasonic techniques. Aperture-diffraction effects are completely avoided by using point emission and detection. The intrinsic character of these measurements is unambiguously demonstrated by the independence of the results with respect to sample length. Furthermore, the broad frequency-band nature of the measurements is used to corroborate Kramers-Kronig relations.