A comparison of signal consistency of common ultrasonic couplants used in the inspection of composite structures

To conduct acousto-ultrasonic tests, the transducers should to be coupled to the structure under consideration with couplants that are generally recommended by the equipment manufacturers. Experiments with several ultrasonic couplants have revealed that one of the factors influencing the repeatability of the results is the type used and that for certain couplants a settling time is required. In this paper a comparison of the signal consistency of common ultrasonic couplants is detailed. The aim of this study was to select the couplant that produces the most repeatable results.