The Research On The Key Technology Of Ultrasonic Phased Array

Ultrasonic phased array testing technology is an advanced ultrasonic nondestructive testing technology. Ultrasonic phased array technology can achieve flexible, controllable synthesized ultrasound beam and freely control the focus point position by exciting each element of ultrasonic array transducer with independent phase delay. With its dynamic focusing, electronic scanning and S-scanning, ultrasonic phased array (UPA) technology can be used for defect detection of objects with complex shapes and can improve the detection sensitivity. Therefore, UPA technology has been becoming a focus of ultrasonic testing researching.This paper discusses the ultrasonic phased array detection related theories, including the principle of ultrasonic radiation field, the principle of phased array ultrasonic testing and the principle of phased array beam control methods. The paper analyses the phased array ultrasonic spatial sound field model, simulates sound field and gets the single-source rectangle, the linear transducer spatial sound field distribution. The deflecting and focusing effects of some array parameters, such as the number of elements(N), the elements pitch(d), the elements width(a), on the ultrasonic beam are thoroughly discussed, which supplies the theory basis for UPA transducer optimal design.Based on the synthesis of phased array focusing approach using signal-channel, a 16-element array, single-channel ultrasonic signal acquisition and processing of experiment system is designed. Test experiments are carried out with this system and defect block. The result of experiment is fitting the actual defects. Results show: this method can achieve the effect of phased array focusing, which greatly improved the detection signal noise ratio and sensitivity, also verify the ultrasonic phased array testing method is feasible. Through the experimental test defect detection, contrast focusing and non-focusing detection experiment results shows that phased array technology can improve the defect detection capability.