This method employs high frequency sound pulses that are emitted from a transducer; this sound wave is induced in to the material through a probe which is usually in contact with the material. These sound waves propagate through the material, and are reflected back to the probe when they reach an interface. The reflected waves are transmitted back through the probe and connecting leads to a detector which can be either analogue or digital. The sounds waves are then displayed as a series of signals on a monitor and the qualified inspector can measure, and interpret these signals to allow accurate evaluation of the internal structure of the material.
Ultrasonic testing can not only be used to indicate a surface or subsurface flaw it can also be used to determine the depth, size and type of flaw. Another advantage of using UT is the accurate measurementof the thickness of the material. The method can be applied to most materials providingthe material can transmit sound waves. UT is considered to be a fast and effectiveway of inspection providing high sensitive results.
The particle oscillation is parallel to the wave propagation direction. Also called as Compression wave.
The particle oscillation is perpendicular to the wave propagation direction. Also called as Transverse wave.
The particle oscillation is neither parallel nor perpendicular to the wave propagation direction. Also called as Rayleigh wave, Lamb wave, Plate wave, Rod wave.