基于超声相控阵的环焊缝缺陷检测方法研究

针对传统超声探头焦距固定,检测位置的改变就要更换相应焦距的探头而影响检测效率的问题,提出一种基于超声相控阵换能器的环焊缝缺陷检测方法。而超声相控阵具有电子偏转和电子聚焦特性,能在不移动的情况下发射偏转聚焦超声束,有效地解决了上述问题。首先基于超声相控线阵换能器的声场特点,采用数值分析方法,研究了影响声束偏转聚焦性能的几个主要参数。然后给出了与超声相控阵换能器相连接的多通道数据采集系统结构。介绍了单通道声信号的硬件结构及相应的信号处理方法,实现了对换能器中单个阵元的精确延时的控制。实验结果表明,优化设计的超声相控线阵换能器具有较高的检测精度和检测效率。

Research on ultrasonic phased array system for pipeline girth weld automatic flaw detection

The traditional ultrasonic probe has fixed focal length, so the change of detection position requires the change of probe for corresponding focal length and the efficiency of detection is seriously influenced. In view of the above problem, a kind of girth weld defects detection method based on ultrasonic phased array transducer is put forward. The ultrasonic phased array is characterized by electronic deflection and electron focusing, and it can release ultrasound beam for deflection focusing without movement, so the above problem can be efficiently solved. Firstly, based on the acoustic field characteristics of ultrasonic phased array transducer, and adopting the numerical analysis method, several main parameters affecting the deflection focusing performance of the beam are studied. Then, the multi-channel data acquisition system structure connected with the ultrasonic phased array transducer is given. The hardware structure of single channel acoustic signal and the corresponding signal processing method are introduced, and the control to precise time delay of the single array element in the transducer is achieved. The experimental results show that the optimally designed ultrasonic phased array transducer has higher detection accuracy and efficiency.