Research on the scattering characteristics of phased array focused ultrasound interacted with hole

Compared with the traditional detection methods, the sound beam focusing control ability of phased array technique makes the resolution, signal-to-noise ratio, sensitivity and other performances of ultrasonic phased array detection effectively improved. But at present, lack of understanding the interaction of phased array focused ultrasound with defects causes the current detection techniques impossible to achieve accurately qualitative and precisely quantitative analysis of defects. Therefore, this paper establishes a finite element model of one-dimensional linear ultrasonic phased array for the detection of hole defects and studies the scattering characteristics of the acoustic field caused by the interaction of the phased array focused beam with the hole defect. The results show that the energy of L mode scattering of the hole is mainly focused on the positive reflection area and the positive transmission area, and the energy in the transmission region is greater than that of the energy in the reflection region, and energy is extremely weak in the direction perpendicular to the direction of incidence, almost no scattering energy. The L mode scattering is axial symmetrical distribution along the direction of incidence. For hole defects of different diameters, the larger the diameter, the greater the energy of the scattering obtains in the same direction. For the same diameter of the hole, the distribution of the scattering energy is the same for focusing wave or plane wave incidence, but the scattering energy of focusing wave is significantly higher than that of plane wave.