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超声锁相热像是以超声频振动做激励源并采用锁相方法对热图信号进行处理,得到热图序列的幅值和相位来判定缺陷的一种红外热像无损检测技术。它能够有效地检测各种材料内接触界面类缺陷。为了提高对缺陷的检测效率和探测能力,基于超声锁相热像技术,对采集的瞬态热图序列进行处理,采用时频分析方法提取瞬态热图序列的相位和幅值。研究固定分析窗宽(分析长度)时窗中心时刻(分析时刻)对检测结果的影响。采用超声红外锁相热像技术对A3钢板材微裂纹进行检测试验研究,结果表明,瞬态热图序列的时频分析方法能够准确检测金属板材的微裂纹缺陷。
Ultrasonic phase-locked thermal imaging is a kind of infrared thermal image non-destructive testing technology which uses ultrasonic vibration as excitation source and uses phase-locked method to process heat map signal to obtain amplitude and phase of thermal map sequence to determine defects. It can effectively detect the contact interface defects in various materials. In order to improve the detection efficiency and detection ability of defects, the acquired transient heat map sequence is processed based on ultrasonic phase-locked thermography, and the phase and amplitude of the transient heat map sequence are extracted by time-frequency analysis. Study fixed window width (analysis length) window center moment (analysis time) on the test results. Ultrasonic infrared phase-locked thermography was used to test the crack of A3 steel plate. The results show that the time-frequency analysis of the transient heat map can accurately detect the micro-cracks in the metal plate.