The Digital Ultrasonic Testing Technology Research Of High-speed Locomotive Axle

Locomotive axle is one of the key parts of the high-speed locomotive,the reliabilityof the axle directly determines the stability and safety of locomotive,So it is necessaryto carry out regular inspection of axle.In all kinds of testing means,ultrasonic flawdetection was widely used in various industrial flaw detection applications because ofits advantages: safe, simple operation and strong penetrating power.This paper mainly discusses the key techniques used in ultrasonic testing of highspeed locomotive axle.The author analyzes the main causes of common defects of theaxle, identifies the key areas of axle inspection and designs a digital ultrasonicinspection system for the axle locomotive.Detection system uses a non tuned circuit,which creates an incentive for ultrasonictransducer.The echo signal is send to a variable gain amplifier circuit,the gain iscontrolled by a control voltage.The A/D circuit convert the analog signal to digitalsignal,then the signal will be saved by a high-speed RAM. The data will eventually betransmitted to the host computer through USB.The host computer software of digital testing system uses Visual Basic6.0todevelops the graphical user interface.The functions of the software includes display,storage of waveform and parameters calculation.In addition,a IIR digital bandpass filteris designed for noise reduction of echo signal, the energy window envelope method andHilbert transform method are used to extract the echo envelope and obtained the signalcharacteristics in time domain.According to the test block and locomotive axle artificial defect detectionexperiments, the system’s stability and accuracy is proved.