Research On The Method Of Rail Flaws Detection Using Ultrasonic Phased Array Based On Linear FM Signal

As mankind enter the new century, the modern industrial rapid development in ultrasonicnondestructive testing technology which plays an important role in the world as a keyresearch to overcome. Ultrasonic testing as one of the most widely used non-destructivetesting technology. Peoples use the sound propagation characteristics to characterize theinternal organization of the characteristics of the work-piece. Detect defects within thework-piece to complete the test, and then locate the defect, qualitative analysis, in thetransportation, petroleum exploration, and medical fields have a strong theoretical andpractical values. Nowadays non-destructive testing has been widely used in the field of railflaw detection based on traditional pulse-echo method. It is the use of the ultrasonic probetransmitting ultrasonic pulses to a subject work-piece, and then according to the energydistribution of the received reflected wave, the phase information to determine the rail defects.However during the rail flaw detection, the probe is always with the rail in the state of therelative movement, the sampling time is not sufficient, there is the problem of the moredetection blind area, so that the detection efficiency is low, the rate can’t be improved. Thus,this article will be focused on the lack of traditional ultrasonic testing method correspondingresearch and make improvements, the main work of this paper include the following fouraspects:1, Proposed phased ultrasonic crawler-based the rail detection device design. The crawleris different from the existing roller detection method, which uses the shoe piece and railcontinuous, prolonged contact with this feature, the transmitter and receiver array signal.2, Proposed the chirp signal rail system detection. It’s strong anti-multipath interferenceand locating the defect resolution capability, good positioning defect. While it largerbandwidth characteristic, reduce the signal transmission power, and is conducive to reducingthe cost of the probe device.3. Proposed estimation method based on chirp signal array the signal echo delay accuracy.No longer dependent on the characteristics of the sound pressure in the conventional ultrasonic testing, launch chirp ultrasound signal as the signal source, the ultrasound arrayecho signal coherent demodulation, echo low frequency sinusoidal part of the correspondingfrequency is estimated using the ESPRIT algorithm. The use of frequency instead obtainedecho delay, delay accuracy.Complete ultrasonic rail inspection system module based on chirp signal simulation. Theexperimental results show that this new method based on the detection of the chirp signalultrasound rail having higher detection accuracy.