相控聚焦超声与圆孔交互作用的散射特性研究

相较于传统超声检测,相控阵技术的声束聚焦控制能力使得相控超声检测的分辨率、信噪比和灵敏度等性能得到有效提升。但针对相控超声与缺陷的交互作用认识不足,导致目前检测技术无法对缺陷进行准确定性和精确定量。为此,建立了一维线阵相控超声检测圆孔缺陷的有限元模型,重点研究相控聚焦波束与圆孔缺陷交互作用的声场散射特性。结果表明,圆孔散射L模态的能量主要集中于正反射区和正透射区,且在透射区的能量大于反射区的能量,而在与入射声束垂直的方向上能量极其微弱,几乎没有散射能量;散射L模态沿入射方向呈轴对称分布;对于不同直径的圆孔缺陷,直径越大,在相同方向上散射波的能量越大;对于相同直径的圆孔,聚焦波与平面波入射时,散射波的分布规律相同,但聚焦波散射的能量明显高于平面波入射时散射的能量。

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.