High-frequency ultrasound-based thickness measurement of highly attenuating materials

Abstract

This paper investigates an effective method for measuring the thickness of highly attenuating materials using the acoustic radiation-induced quasi-static component (QSC) of a primary longitudinal wave (PLW) at high frequency. The generated QSC features lower attenuation than the high-frequency PLW, so the generated QSC pulse with zero carrier frequency can propagate a longer distance at the same group velocity, even in highly attenuating materials. In addition, the method based on the QSC of a high-frequency PLW has better directivity than the low-frequency PLW-based method, making it more suitable for highly attenuated material local thickness measurement. The thickness of highly attenuating materials can be accurately measured by measuring the pulse-echo time-of-flight of the generated QSC pulse using an ultrasound pulse-echo technique. The experimental examinations conducted for highly attenuating silicone rubber blocks with different thicknesses demonstrate that their thicknesses can be accurately measured with the QSC-based method. This paper provides an effective method for thickness measurements of highly attenuating materials.