Journal of Mining & Safety Engineering ›› 2012, Vol. 29 ›› Issue (3): 328-333.

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Nondestructive Testing Principle and Technology of Hydraulic Supports by Ultrasonic Phased Array in Top Coal Caving Face

  

  • Received:2011-06-12 Online:2012-05-15 Published:2012-04-12

Abstract: ased on the necessity of nondestructive testing of hydraulic supports in top coal caving face, the nondestructive testing technology of one-dimensional ultrasonic phased array was proposed in this paper, to accurately inspect the large-scale electromechanical equipment and its components with relatively complex geometric figures. According to the mobile column detection of ZFG10000/23/37H hydraulic supports, the basic principles of phase-controlled focus and phase delay was conducted. Combined with the normalized acoustic pressure function of single element, the significance of sine gain weighted apodization technology was analyzed when applied into reducing the definition of output waveform influenced by sidelobe. Finally, in view of the detection of weld cracking shields at 5201 working face in Wujiagou coalmine, the composition and testing process of nondestructive detection were illuminated. The application examples indicate that the internal micro-fractures and surface interpenetrated fractures of shields can be accurately quantified and located by nondestructive testing technology of one-dimensional ultrasonic phased array, and the development direction and interpenetrated tendency of the fractures can be also exactly judged, according to the results of three-dimensional imaging output.

Key words: ultrasonic phased array, phase delay, dynamic apodization, phase quantification error