基于水平分置线性双阵列的超声全聚焦成像方法在粗晶材料检测中的应用

针对粗晶材料超声检测信噪比低的问题，提出了一种水平分置线性双阵列超声成像方法。将两个线阵超声换能器沿直线水平分置在待检区域表面两侧，用收发分离的信号采集模式，一侧激发，另一侧记录各通道数据，进行聚焦成像。相比单阵列和同位置双线阵检测，文中的方法有效地减少了背向散射信号对缺陷信号的干扰，提高了成像信噪比。在粗晶铜质试块上的成像实验结果表明，当缺陷距离阵列较近时，文中的方法优于单阵列和同位置双线阵方法，成像信噪比提高约5～10 dB；当缺陷距离阵列较远时，单阵列模式和同位置双线阵检测方法失效，但文中的方法依然可以识别缺陷。文中的研究为粗晶材料的超声检测提供了一种可行的方案。

Application of ultrasonic total focusing method in the detection of grained materials based on a horizontal dual linear array setup

Ultrasonic testing is difficult to detect flaws in grained materials because of the low flaw signal-to-grain noise ratio. In this paper, an ultrasonic imaging method based on a horizontal dual linear array (HDLA) setup is proposed. The two linear arrays are arranged on both sides of the surface of the area to be detected. One of the transducer arrays excites the ultrasonic wave, while the other records the data of each channel, and finally focused imaging is performed. Compared with the single array and the one-side dual linear arrays (DLA) setup modes, this method effectively reduces the interference of strong backscattered signals in grained materials and improves the signal to noise ratio (SNR) of images. The imaging experimental results on grained copper samples show that the imaging SNR of the proposed method is improved by about 5~10 dB compared with the other two modes of single array and DLA, when the flaw is close to the array. When the flaw is far away from the array the single array mode and DLA mode fail, however, the HDLA method can still identify the flaw. This method provides a possible scheme for ultrasonic testing of grained materials.