管道導(dǎo)波檢測中激發(fā)頻率的選擇及靈敏度分析

管道導(dǎo)波檢測中激發(fā)頻率的選擇及靈敏度分析

采用超聲縱向?qū)Р▽峤粨Q管進(jìn)行檢測。首先利用導(dǎo)波的頻散曲線，選定了檢測的最佳導(dǎo)波模式I(O,2)，然后用位移分布、應(yīng)力分布及總能量密度分布等選取了用該模式檢測特定管道的頻厚積，最后通過試驗分析了管道導(dǎo)波檢測的靈敏度。試驗結(jié)果表明，L(O，2)模式的波長比缺陷尺寸大10倍時，也能非常清楚地檢測到缺陷。

The heat-exchanger pipes could be inspected by ultrasonic longitudinal guided waves．Firstly the optimal testing mode L(O，2)was selected according to the dispersion curves of guided waves，then the frequencythickness product was chosen according t0 the displacement，stress and total energy density(TED)amplitude distributions．Finally，the sensitivity of testing was analyzed in the experiment．Results showed that the defects inpipes could be detected distinctly even if the wavelength of L(O，2)mode was 10 times longer than the defect size．