碳纤维复合材料层板冲击损伤的空气耦合兰姆波成像检测

非接触式超声兰姆波方法能够对大面积复合材料板材进行快速检测,在自动成像检测上有着突出的优势。针对碳纤维/树脂基复合材料(CFRP)层压板采用空气耦合超声探头激励出A0模态兰姆波。在含冲击损伤的层板试样的同一侧激发和接收兰姆波进行扫描检测,针对冲击损伤区域以互相正交的两个方向进行兰姆波扫查,获得了不同位置的检测信号。对比在有无缺陷处板材中兰姆波传播信号的特征,对采集信号进行频域分析,以无缺陷处信号值为基准,利用信号差异系数(SDC)作为特征值,将扫查信号数据采用特征值全加和全乘的数据融合方法进行了缺陷形貌重构成像。成像结果能够良好的体现出冲击损伤的位置和两个方向的尺寸大小。

Imaging of CFRP Plate Impact Damage Using Air-Coupled Lamb Waves

The non-contact ultrasonic Lamb wave method can detect the large area composite sheet quickly and has the outstanding advantages in the automatic imaging detection. A0 mode lamb waves were excited by air-coupled ultrasonic probes for carbon fiber reinforced resin (CFRP) composites laminates. The Lamb waves were scanned and detected on the same side of the sample with the impact damage, and the Lamb waves were scanned in two directions which are orthogonal to each other to obtain the detection signals at different positions. Based on the characteristics of the Lamb wave propagation signal in the without defects and with defects plates, the frequency domain analysis of the acquisition signal is carried out. It is caculated for signal difference coefficient (SDC) based on no defects area signal.And SDC is used as characteristic value, the scanning imaging is achieved form characteristic value by using full summation algorithm and full multiplication algorithm data fusion method. Contrast of the amplitude imaging scan,the SDC imaging results are able to reflect the position of impact damage more,and it can show the impact size in two directions.