Absolute Measurements of Particle Velocity, Displacement or Intensity of Ultrasonic Pulses in Liquids and Solids

Absolute methods for quantitative measurements of ultrasonic pulses in liquids and solids are described and discussed.

In the first method a special electrodynamic transducer is applied to the measurement of particle velocity of ultrasonic pulses propagating in liquids. The wave being measured falls upon the coil winding evaporated onto a perspex insulator, which is placed in the field of a permanent magnet.

In the second method the capacitance is used, the capacitance being formed by an electrode immovable with respect to the free surface of an aluminium plate immersed in the liquid. Displacement measurements in the propagating pulse are made with this transducer.

A similar capacitance transducer is used for displacement measurements of longitudinal and transverse waves in solids. In the last case the transverse wave is converted into the longitudinal component by reflection at an oblique free surface of the solid.

Also an electric impedance method is applied to intensity measurements of pulses radiated into solids.

As examples, measurements of particle velocity, displacement and intensity of ultrasonic pulses propagating in liquid and solid are given. The differences in intensities obtained on the basis of these measurements performed with the methods described are found to be ca. 1 dB.