基于超声复解析信号的碳纤维层压复合材料检测方法研究

Research on Ultrasonic Testing Method for Carbon Fiber Laminated Composite Using Ultrasonic Analytical Signal

采用超声波检测碳纤维层压复合材料时,换能器将接收到层间产生的反射信号。为了有效利用层间反射信号表征碳纤维层压复合材料内部树脂及纤维铺层的几何状态,开展基于超声复解析信号的检测方法研究。介绍超声复解析信号的基本理论,阐述其相对原始A型信号的优势;定义用于成像的复解析信号表征参量,设计基于表征参量的检测成像算法,采用简化声学模型分析碳纤维层压复合材料微观结构超声响应对表征参量的影响;针对包含冲击损伤的碳纤维增强复合材料层压板开展阵列超声检测试验,试验结果表明基于超声复解析信号的检测成像方法可清晰观测出碳纤维层压复合材料微观结构内部的纤维铺层几何形态,基于原始A型信号的检测成像方法无法有效观测,超声复解析信号具有用于表征评价复合材料脱层、褶皱等缺陷的巨大潜力。

In ultrasonic testing of carbon fiber laminated composite, A-Scan signal received by transducer contains information about inner layer reflections. To effectively characterize resin and fiber ply by inner layer reflections, research on ultrasonic testing method using analytical ultrasonic signal is conducted. Firstly, basic concepts about ultrasonic analytical signal and its advantages over raw A-Scan signal are introduced. Secondly, ultrasonic analytical signal parameters and imaging algorithm based on them are designed, the relations between analytical signal parameters and microstructures of carbon fiber laminated composite are analyzed based on a simplified 1-D acoustic model. Finally, ultrasonic array testing experiment on a carbon fiber composite laminate sample with impact damage is conducted. Experiment results show that the fiber ply geometry can be clearly observed by imaging algorithms using analytical signal, which is difficult to be obtained by using raw A-Scan signal. Testing methods based on ultrasonic analytical signal are promising to evaluate defects of carbon fiber laminated composite such as delamination and ply wrinkle.