The Impacts of Structure Position and Size Change on Ultrasonic Transmission Properties

Abstract

Based on the finite differential time-domain (FDTD) method, two types of aluminum plate samples with one and two circular cavities are established. The ultrasonic transmission signal and acoustic pressure distribution for samples with different cavity positions (x) and diameters (d) are obtained through FDTD simulations. The results show that when x is between 6 wavelengths (15 mm) and 14 wavelengths (35 mm) of the ultrasound, the power of the transmitted ultrasonic signal increases dramatically for the two cavity diameters of d = 2λ and d = λ. Such an increase is especially large when the cavity is in the middle and the maximum relative change is about 260% when d = 2λ. However, the power does not change much with changing x and is close to the sample with no cavity when d = 0.5λ. It also shows that the transmitted power is weakened for the sample with two cavities due to the coupling effect between them. These results may have potential use in ultrasonic detection.