Design And Application Of Ultrasonic Phased Array Flaw Detection System

Ultrasonic testing(UT)is one of the most popular testing approaches in the industrial fields,and ultrasonic phased array technology is an important research direction of UT.Compared with the traditional ultrasonic testing,phased array ultrasonic technology has advantages including higher effecency,higher signal noise ratio and greater ablity to inspect the defects,and the technology also made it possible to inspect units with complex geometrical shape.The core points of ultrasonic phased array technology are ultrasonic wave generating,beam forming,design of high voltage supplier,high speed multi-channal synchronous signal acquiring and processing,imaging algorithm,etc.It is believed that the equipments would be more integrated with higher image quality and more intelligent,making the ultrasonic phased array technology more powerful in the field of Non-destructive Testing.This paper introduced the design of a 64-channal ultrasonic phased array inspecting system,including its hardware and software.First of all,the concepts about the ultrasonic phased array are introduced.Then the sound field model of linear phased array is built.The calculation of delay laws and imaging algorithms are also discussed.Secondly,the hardware design of the ultrasonic phased array inspection system is introduced in detail.The system designed in this paper supports up to 64 ultrasonic emission channels and 16 synchronous echo acquisition channels.The sampling rate is up to 65 Msps,and the sampling depth is up to 4096 sampling pionts.The emission voltage is tunable between 4.5V and 90 V.The max delay between different elements is 2?s,and the accuracy of the delay is 2ns.Some approaches to improve the hardware system are also listed.Thirdly,the software design of the system is presented,which includes the firmware design of USB controller,the program in FPGA and the user program based on LabVIEW.Finally,the ultrasonic phased array inspection system is verified by experiments.Besides,a method to generate high qulity three-dimensional defects images is proposed,whose effectiveness is proved by experiments.