Acoustic waveguides having a varying velocity distribution with reduced trailing echoes

摘要

Acoustic buffer rods are useful in the nondestructive ultrasonic evaluation of materials. In order to reduce the occurrence of spurious signals in the reflected acoustic waves forming an acoustic "image" of a sample, it is proposed to design buffer rods such that their radial acoustic velocity profile is graded, preferably having a parabolic shape. The lowest acoustic velocity of the buffer rod is in its center, i. e. at the longitudinal axis of the rod. This design is applicable to both uncladded buffer rods as well as to the core of cladded ones.