The Journal of the Acoustical Society of America · 1961 · 632 citations · 0 references
Natural SciencesMaterials ScienceAcousticsMaterials CharacterizationUltrasoundAcoustic MeasurementAcoustic Wave PropagationPhysical AcousticsTransducer TechnologyUltrasonicsUltrasound PhysicsPhase AnglePhase DelaySpeed Of Sound MeasurementUltrasonic AcousticsUltrasonic ReflectionUltrasonic TransducersUltrasonic Wave MeasurementUltrasonic Waves
The pulse method for ultrasonic velocity measurement uses a high‑frequency quartz transducer bonded to a specimen, and accurate results require accounting for the transducer’s reflection phase shift. By combining phase‑delay measurements at two frequencies separated by ~10 % and modeling the reflection phase angle, the method determines velocity to within one part in 5000 for round‑trip delays over 5 µs, also enabling estimation of the transducer‑specimen bond thickness and facilitating temperature or pressure dependent studies.
The frequently used pulse method of measuring ultrasonic wave velocities in solids involves a high-frequency quartz crystal transducer cemented to one end of a specimen having parallel end faces. The phase shift for waves reflected from the transducer must be considered for highest accuracy. It is shown that combining several measurements of phase delay (at two frequencies differing by approximately 10%) with a theoretical analysis of the reflection phase angle makes possible a determination of velocity to within one part in 5000 for round trip delays greater than 5 μsec. Indirectly, the approximate thickness of the cement bond between transducer and specimen can be determined. The advantages of the method for making measurements as a function of temperature or pressure are discussed.