Effect of Coupling Conditions on Ultrasonic Echo Parameters

In the pulse echo method of ultrasonic non-destructive testing, the signal reflected from opposite face is studied. An analysis of this signal reveals important information about the characteristics of the material through which ultrasonic waves have propagated. Any change in a material characteristic will change signal parameters to varying extent. However, signal parameters can also get affected by the conditions of couplant used between the transducer and material. In the present paper, effects of coupling conditions on signal (echo) parameters have been studied. A detailed analysis is given on various echo parameters such as peak frequency, amplitude, their ratios, etc. for first and second back wall echoes.