Design Of Phased Array Ultrasonic Testing System Based On LabVIEW

Ultrasonic phased array testing technology is one of the most important modern nondestructive testing technology. The flexible control for the synthesis of beam deflection Angle and the depth of focus is realized by the control of incentives or receive ultrasonic phase delay of each ultrasonic probe in the array. With a better signal to noise ratio and higher testing efficiency, combined with modern digital technology and the development of information technology, the ultrasonic phased array detection technology has become a hot spot for industry research all over the world, and it tends to replace the conventional ultrasonic testing gradually.The basic principle of ultrasonic phased array testing analyzed, then the advantages and disadvantages of the synthetic aperture focusing and synthesized focusing are discussed and compared, and the combination of the two approaches above is used for the design of ultrasonic phased array testing system in this paper.Parts of the system hardware devices are designed, such as ultrasonic emission circuit and so on, at the same time, to achieve the purpose of automated testing system, the channel selector device is designed, with which a programmable gating is realized. Based on the hardwares such as piezoelectric array, computer, acquisition card, and channel selector device, amplification, filter and so on, all the software modules of the system was designed, and with the system integration technology, all software modules are integrated together, for the convenience of user controling.For the data processing part, it costs much time caused by large computational complexity, A distributed network computing system based on LabVIEW platform is proposed and realized, which is in accordance with the master-slave structure, the host is responsible for the coordination control and data summary, and all slave machines, embedded with ultrasonic phased array data processing algorithm, are under the coordination control of the host, in this way the purpose of parallel computing is achieved, which can significantly improve the speed of data processing, comparing to the FPGA, this system has the advantage of cost and has a good perform in data processing. And this part is integrated into the main software too.An experimental verification is proceeded based on the system designed in this paper with the help of a metal specimen which contains a defect, the parameters of incentives, acquisition, management are setted in the software of the system. Focusing and synthesising of various sites in the longitudinal section that contains the array probes of the specimen is proceeded by the software. It shows that with the phased-array synthesis focus method proposed in this article the strength of characteristic signal can be effectively enhanced, and the amplitude of the interference signal can be restrained either. And the signal-to-noise ratio of defect signals are significantly improved through the analysis of the synthesized signal of each sites. By extracting and normalizing all the synthetic signal amplitude of all sites, the two-dimensional imaging of the longitudinal section of the specimen is realized, and the defect can be accurately located from the imaging results. Finally, a performance verification of the proposed distributed computing system for ultrasonic phased array data processing in this paper is operated,which turns out that the speed of data processing has been significantly improved with this system.