楔块中脉冲声场及相控阵成像自检研究

相控阵横波检测必须在换能器前方加上楔块,对于楔块中的声场进行研究具有重要意义。本文通过数值计算和物理实验研究了超声相控阵楔块中的脉冲声场,分析并解释了超声相控阵系统自检成像过程中各种波形的产生机理和转换过程。首先从固体中超声传播理论出发,采用时域有限差分方法对相控阵楔块中各阵元独立发射条件下的脉冲声场进行仿真计算,给出了超声脉冲在楔块中的传播过程;然后开展了对应边界条件下相控阵楔块的B模式成像实验。数值模拟和物理实验的结果基本一致。本文的研究初步展示了楔块中的脉冲声场,其结果可为超声相控阵系统自检和楔块设计提供参考。

Ultrasonic field of pulse wave in wedge and self-checking for imaging by phased array

As a wedge must be used in phased array shear wave testing, a research on ultrasonic field of pulsed wave in a wedge is very significant. Ultrasonic field of pulse wave in a phased array wedge is studied through numerical calculations and experiments. The mechanism of production and conversions of all kinds of waves in self-checking images are analyzed and explained in detail. At first, finite-difference time-domain(FDTD) method is used to compute the ultrasonic field of pulse wave in the wedge based on the theory of ultrasound propagation in solid and the propagation process of ultrasonic pulse wave is given when each element of the transducer works independently. Then B-mode imaging experiments with different boundary conditions are conducted. It shows that the experimental results agree with the simulation results. This study may be useful for self-checking of ultrasonic phased array system and designing of the wedge.