Research On The Testing Of The Light-Rail's Anchoring Screws On Duty Based On Ultrasonic

The screws assembled on Light-rail of Chongqing are the key research object of this paper. Since they are the most important part forced to connect pier and girder of Light-rail, their health makes the key point of the Light-rail's daily function. So supervision and detection of the fieldwork anchoring screws of the light-rail are very important.With many merits such as accurate quantitation and orientation of flaw in the materials, long range of detection fiends, high sensitivity and low cost. UT technology has become a very important method in NDT area. A lot of kinds of digital ultrasonic defectoscopes have been presented to home market in late years, but more or less, they are loss of universality and low ability of analyzing and processing the signal. Therefore after analyzed the characteristics of the fieldwork anchoring screws of the light-rail, This paper designed a testing system to the fieldwork anchoring screws based on ultrasonic, including the whole project design, the choice of hardware and software design, and explains the design flow concretely.For the sake of signal analyzing later, we have done some pretreatments to the ultrasonic signal, including the zero mean processing and the eliminating the noises. and emphasized the operation of wavelet analyzing in the ultrasonic signal de-noising. aiming at the disadvantages of the traditional thresholding functions, we put forward a method of ultrasonic signal de-noising in wavelet domain based on a kind of an improved thresholding function and proved the validity and superiority of this method by idiographic examples.By the ultrasonic signal sampled ,we analyzed the disease characteristics of the anchoring screws, and by a lot of samples, concluded the characteristics of ultrasonic signal of the anchoring screws and the method to recognize the unreal signal,and increased the reliability of the ultrasonic NDT.It is concluded the status of the project at the end of this paper, and put forward some expectations, which pointed out the research direction in the future.