中文摘要：

为了准确识别复合材料板低速冲击信号，搭建了基于光纤Bragg光栅（FBG）传感器应变敏感特性的复合材料板冲击监测系统，分析了基于经验模态分解（EMD）的冲击信号特征提取方法，研究了基于信号特征提取的冲击信号方向判别。通过试验监测了在距离相等的情况下与传感器轴向角度为0°，15°，30°，45°，60°，75°，90°方向的冲击信号，分析得出冲击信号方向与EMD所得特征值呈余弦关系。结果表明：利用光纤传感技术和EMD法可精确判别低速冲击信号方向。

英文摘要：

In order to discriminate signals under low velocity impact of composite plate accurately, an impact monitoring system for composite plate based on strain sensitive characteristic of fiber Bragg grating（FBG） sensor is established, feature extraction method for impact signals, based on empirical mode decomposition （EMD） is analyzed, and direction discrimination method for impact signal based on signal feature extraction is researched. The experiment is conducted to monitor the impact signals with angles of 0°, 15°,30°,45°,60° ,75° and 90° to the sensor axial direction in equal distance, and obtain the cosine relationship between impact signal directions and EMD characteristics value. The experimental results show that using FBG technology and EMD method can recognize accurately signal direction under low velocity impact.