复合材料层压板钻孔分层激光超声检测方法

飞机复合材料结构钻孔分层的定位、定量检测是无损检测领域的难点之一，也是航空制造领域亟待解决的安全问题之一，激光超声检测技术是解决该问题的可能途径。试验验证利用激光超声检测复合材料钻孔分层的技术可行性。制备复合材料层压板钻孔试样，研究热弹性条件下脉冲激光在复合材料中产生超声波的宽频带特性，提取出满足检测灵敏度、分辨力要求并具有良好信噪比的超声信号；分析近孔边缘分层界面对声传播规律的影响，得出钻孔边缘分层缺陷的激光超声表征方法；采用脉冲反射法、透射法对复合材料钻孔试样进行激光超声C扫描检测，获得钻孔分层缺陷的形貌、尺寸和位置特征。研究结果表明，激光超声检测技术是解决飞机复合材料结构钻孔分层检测问题的有效手段。

Laser Ultrasonic Detection of Drilling-induced Delamination in Composite Laminates

The positioning and quantitative testing of drilling-induced delamination in aircraft composite structures is not only one of the main difficulties in the field of non-destructive testing(NDT), but also a security problem need to be solved in aviation industry. Laser ultrasonic testing technique is a possible way to solve the problem. An experiment study concerning the verification of the feasibility of detecting drilling-induced delamination with laser ultrasonic technique is carried out. A composite laminate with drilling holes is made as specimen, the broadband characteristics of ultrasonic waves in composites generated by pulse laser are studied, and the wave signals with good signal-to-noise ratio(SNR), high sensitivity and resolution are extracted. The effects of the interface of drilling-induced delamination on the propagation characteristics of laser ultrasonic waves are studied, and the characterization methods of drilling-induced delamination with laser ultrasonics are acquired. Based on the pulse echo and transmission method, the laser ultrasonic C scan testing of the composite laminate with drilling holes is accomplished, and the morphologies, dimensions and positions of drilling-induced delamination are obtained. The research results show that laser ultrasonic testing is an effective method to detect the drilling-induced delamination in aircraft composite structures.