A SWITCHING TECHNIQUE FOR MEASURING HIGH ULTRASONIC ATTENUATION

A new experimental technique for measuring the ultrasonic attenuation coefficient in a highly attenuating material such as concrete is presented. In this technique, the first through-transmitted and first reflected signal are obtained in two measurement configurations (initial and switched) using contact transducers attached on both sides of the material sample. In the switched configuration, the electrical connections of the transmitter and receiver are interchanged with all other conditions including the coupling between the transducers and the material kept the same as in the initial configuration. The attenuation coefficient is then calculated from the product of two transfer functions defined with the signals measured in these two configurations. Effects of the partial reflection from the transducer-material interface on the attenuation measurement and how this can be compensated for are discussed. The capability of the proposed technique is examined with plastic and concrete samples.