采用高分辨率超声成像方法实现复合材料冲击损伤的无损检测,以高品质的脉冲超声波作为探测源,提取入射声波在复合材料层压结构试样中形成的时域反射声波信息,并通过扫描结构使换能器对含有冲击损伤的复合材料试样进行自动扫描,实时对每一个检测位置点的超声信号和位置信号进行处理与融合,通过超声B扫描成像和T扫描成像进行复合材料冲击损伤成像评估。试验结果表明:通过超声B扫描成像,可以形象地再现复合材料层压结构试样表面和内部冲击损伤在其不同深度方向的断面分布、取向、扩展及深度等确切信息;通过超声T扫描成像,则可以直观地再现冲击损伤在复合材料层压结构试样不同深度铺层方向的损伤区域(面积)、分布及其扩展特征。

Impact damage is kind of harmful defect for composite structural safety, which is easy induced during manufacturing and in-service. A high resolution pulse ultrasonic imaging technique based on the interaction of probe ultrasound with carbon fiber-reinforced composite laminate was employed to NDT&T of impact damage. A high quality impulse ultrasonic focal beam was used as probe ultrasound. Signals reflected from the composite laminate body were captured by data acquisition unit when focal transducer scanned composite specimen with impact damage. In the same time, ultrasonic scanning system recorded all the data of ultrasonic signals and transducer positions. B-scan and T-scan imaging based on the data were organized to investigate and evaluate impact damage in the composite specimen. Experimental results showed that the exact distribution, orientation, evolving and depth of impact damage were seen well in cross-section of the specimen by B-scan imaging. The destructive area, configuration and development of the impact damage in different depth of specimen lay-up were exhibited well by means of T-scan imaging.