A model for the propagation of short pulses of ultrasound in a solid

Abstract

A simple model has been introduced which allows calculations to be made of the particle displacement and velocity waveforms which arise when short pulses of ultrasound are radiated into solid media from transducers typical of those used in nondestructive evaluation. The model makes use of the plane- and edge-wave nature of the pulses radiated and, for simplicity, incorporates an empirical extension of the impulse response method for propagation in a fluid medium. Calculations made using the model are compared with other theoretical results obtained previously by harmonic synthesis, as well as with experimental measurements of pulse waveforms made using a miniature piezoelectric receiving probe. The results obtained are of particular relevance to the characterization of small targets using ultrasound.

Acoustic methods for obtaining the pressure reflection coefficient from a buffer rod based measurement cell

“…The effect of this is given in (30)- (32). If the transducer needs to be remounted between the measurements, then the relevant equations read…”

“…A particular component of the systematic noise is the interference effect from the conversion of shear wave to compressional wave at the buffer-sample interface [32]. Using echo signals that do not interfere with such systematic noise components will be beneficial as the measurement of the echo signal's amplitudes leading to the reflection coefficient otherwise will be in error [30].…”

Overview of Mathematical Modeling in Nondestructive Evaluation (NDE)

“…Introductions to transducer modeling can be found in Harris (1981), Weight (1987), Krautkramer and Krautkramer (1990), Lhemery( 1994a) and .…”

“…The software package, PZFlex, developed by Weidlinger Associates, was designed to simulate piezoelectric transducers using FEM. Weight (1987) used the geometric theory of diffraction to approximate the field generated by transducers. Schmerr and Sedov (1988) used high frequency asymptotic solutions to obtain simple analytical expressions for the radiated elastodynamic field.…”

A novel approach to acoustic liquid density measurements using a buffer rod based measuring cell

“…This is obtained by avoiding interfering signals. To be able to achieve the maximum purity signals sought for, the following well-known wave-propagation effects in solids [26] must be accounted for: compression plane wave, compression edge wave, and shear edge wave. These waves get mode converted at interfaces where a solid meets a solid or a fluid.…”