A new technique is developed to determine the dispersion relation and the propagational speeds of waves in dispersive solids. The phase spectrum of a broadband pulse is linearly related to the dispersion relation of the dispersive medium. The method is simpler than the continuous‐wave phase comparison technique. Application is made to measure the phase and group velocities of waves in fiber‐reinforced composite materials and in thin wires. This technique is expected to be applicable to measurements of acoustic or electromagnetic wave speeds in other dispersive media.

On the determination of phase and group velocities of dispersive waves in solids

Damage measurements in concrete via an ultrasonic technique. Part I experiment

Estimation of ultrasound attenuation and dispersion using short time Fourier transform

A broad band spectroscopy method for ultrasound wave velocity and attenuation measurement in dispersive media.

On observe une dispersion des ondes stationnaires et des frequences de coupure dans des alveolaires soumis a des vibrations de torsion; les effets sont attribues a des micro-vibrations des parois de l'alveolaire. Les frequences de coupure dans les alveolaires re-entrants a coefficient de Poisson negatif sont inferieures a celles des alveolaires conventionnels dont ils sont derives

Dynamic wave dispersion and less properties of conventional and negative Poisson's ratio polymeric cellular materials

The method of phase comparison of continuous waves is applied to determine the dispersion relation, phase, and group velocities as a function of frequency of dispersive materials. A combination of the variable frequency method and the variable path‐length method is found necessary to eliminate any uncertainty in the dispersion relation determination. Experiments are performed on specimens of various thickness. A constraint equation can be derived since the dispersion relation is unique and independent of the specimen thickness. This equation provides a procedure for determining the absolute number of wavelengths in the specimen. Measurements in unidirectional, fiber‐reinforced boron–epoxy specimens show good agreement with results reported previously.

C. S. Ting

Papers

Measurement of ultrasonic dispersion by phase comparison of continuous harmonic waves