Phase Velocity Measurements in Dispersive Materials by Narrow-Band Burst Phase Comparison.
Abstract
A new method for the measurement of phase velocity of ultrasonic waves by phase comparison of narrow-band bursts is described. The method was developed for the determination of properties such as elastic moduli of composites or other materials in which phase velocity varies with frequency. In such dispersive materials, individual cycles within a burst travel at a velocity different than for the burst as a whole. The new method is based on the phase comparison of entering and emerging sinusoidally-shaped bursts. Two wideband transducers and a buffer are used for reference. The specimen is interposed between a set of transducers and buffer identical with the reference set. Bursts are fed to the two assemblages and the phases of the signals after transmission are compared. The signal is varied from low to high ultrasonic frequencies while in-phase and out-of-phase conditions and frequencies are recorded. From the data, phase velocity is calculated at each recorded frequency. The method and some results are discussed. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 01, 1976
- Accession Number
- ADA033903
Entities
People
- Anthony G. Martin
Organizations
- United States Army Research Laboratory