Development of Hertzian contact ultrasonic probe for couplant-free concrete measurement

摘要

For evaluation of aged concrete structure, it is expected to apply ultrasonic nondestructive measurement. Special coupling media with high viscosity made scanning difficult and the application to huge structure was not practical. Our group prototyped a couplant-free probe realizing strong acoustic coupling using high pressure due to Hertzian contact and found a potential to excite longitudinal wave. However, unexpected frequency decrease was observed. In this study, we aim to reveal a mechanism of frequency reduction and develop transmission-and-reception system applicable to concrete structure.