Automatic determination of acoustic plate source-detector separation from one waveform.

We discuss an automated procedure for determining the separation between a transient acoustic source and a detector on a plate. We use a time-estimation algorithm based on the assumption that the detected signal is represented by a small, finite number of discrete band-limited impulses. This is carried out using the MUSIC (MUltiple SIgnal Classification) algorithm in time-estimation mode to automatically estimate both the first arrival time of the lowest order antisymmetric (Ao) mode and the arrival time of the Rayleigh wave.

Measurements of the longitudinal wave speed in thin materials using a wideband PVDF transducer.

A flat transducer was constructed, using a 9-microm-thick PVDF (polyvinylidene fluoride) film for generation and detection of high-frequency ultrasonic waves, and used for measurements of the phase velocity of longitudinal waves traveling along the thickness direction in a very thin material. The transducer has a useful wideband frequency characteristic extending from 10 MHz to over 150 MHz. Measurements of the phase velocity of the longitudinal waves are carried out using a 0.

Wideband high-frequency line-focus PVDF transducer for materials characterization.

This paper presents the design, fabrication, operating characteristics and applications of a wideband, high-frequency, line-focus beam transducer we constructed using a 9 microm thick piezoelectric polyvinylidene fluoride (PVDF) film. This transducer possesses a focal length of 2.38 mm and an aperture angle of 84 degrees.

A time-resolved method for nonlinear ultrasonic measurements.

We describe a time-resolved method for measuring nonlinear ultrasonic phenomena. Current approaches rely on a narrowband measurement of harmonic generation to identify and characterize nonlinearity. Concomitant with these techniques is poor time resolution.