基于频率调谐和相控阵的金属板损伤检测

Study on Metal Plate Damage Detection Based on Frequency Tuning and Phased Array

基于兰姆(Lamb)波的无损检测方法已成为板类结构损伤检测的重要手段之一。然而,Lamb波的多模态与频散特性,使其在传播及信号处理方面有很大的复杂性。该文将Lamb波应用于线性相控阵损伤检测研究,采用频率调谐理论,获得频散效应弱的S_0波,对板状结构中裂纹型刻槽损伤,进行直观成像和精确定位。仿真与实验表明,频率调谐法可优选出弱频散的S_0模态用于损伤检测,结合线性相控阵列,可对损伤类型及方位做出判断,得到有效的损伤检测信息。

The non-destructive testing based on Lamb waves has become one of the important means of damage detection of plate-like structures.However,the multimode and dispersion characteristics of Lamb waves make them have great complexity in propagation,reception and signal processing.The ultrasonic Lamb waves were applied to study the linear phased array damage detecting.By using the frequency tuning theory,an S_0 mode with low frequency dispersion was obtained.The intuitive imaging and precise positioning of the cracked groove damage in the plate structures can realized.The simulation and experiment results showed that the frequency tuning method could be used to optimize the S_0 mode with weak dispersion for damage detection,and combining with the linear phased array,the type and orientation of damage could be determined,the effective damage detection information could be obtained as well.