超聲波簡(jiǎn)介及其應(yīng)用外文翻譯-在線瀏覽
2025-07-30 16:05本頁(yè)面
【正文】 detection on defects are not intuitive, testing of technical difficulty, vulnerable to subjective and objective factors, and inspection results are not easy to hold, ultrasonic testing requirements on the work surface smooth, requiring experienced inspectors to identify defects types, suitable for the part of considerable thickness inspection, ultrasonic inspection has its limitations. Variety of ultrasonic flaw detector, but most widely application of pulse echo ultrasonic flaw detector. In general, in uniform material, presence of defect will create material discontinuity, this often acoustic impedance of the discontinuity is inconsistent , by the reflection theorem we know that, in two different acoustic impedance by ultrasonic reflection on the interface of media occurs. Size and interface on both sides of the reflected energy media differences in acoustic impedance and orientation, relative to the size of the interface. Pulse echo ultrasonic flaw detector is designed according to this principle. Most of pulse echo ultrasonic flaw detector is a scan, the socalled Ascan display is the way the display of ultrasonic detection in materials is the horizontal coordinate of transmission time or distance, the ordinate is the amplitude of ultrasonic reflected wave. Such as , in a workpiece in the exists a defects , because defects of exists , between defects and material formed a different media junction surface, interface of sound impedance different , when launch of ultrasonic encountered this interface will occurs reflection , reflection back of energy and probe received it, in monitor screen in the horizontal of must of location on will display out a reflection wave of waveform , horizontal of this location is defects wave in was detection material in the of depth . The reflected wave height and shape of different because of different defects, reflecting the nature of the defect Now is usually on the measured object, human launch industrial materials such as ultrasound, and then use its reflection, Doppler effect, transmission to get the formation of internal information and processing of measured object image. Ultrasonic flaw detector which more general Doppler effect method is using ultrasonic in encountered movement of object Shi occurs of more general Doppler frequency moved effect to came the object of movement direction and speed , characteristics 。 transmission rule is by analysis ultrasonic perating had was measuring object of changes and came object of internal characteristics of , its application currently also is development stage 。 receives the reflected ultrasonic waves when the piezoelectric crystals, there will be
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