Measurements on Rayleigh and Lamb wave dispersion curves using PVDF line-focus transducers

Line-focus PVDF transducers have been used successfully in measuring surface acoustic wave velocity for both isotropic and anisotropic bulk materials. However, most of the results are limited to non-dispersive surface wave measurements. In this paper the transducer and its defocusing measurement method will be further used for measuring velocity dispersion of waves propagating in thin plates and layered media. To achieve this, a new waveform processing method is adopted. Measurements on two samples including a thin glass plate and a single-layer/substrate layered medium have been carried out experimentally. Experimental results are in good agreement to the theoretical values. This shows that the wave dispersion curves can be determined accurately with line-focus PVDF transducer and the new waveform processing method.