【摘要】 由于复合材料结构先验知识获取的困难性及多传感器动态监测的冗余性,提出了一种基于归一化互相关的单传感器冲击定位方法,并搭建了单传感器复合材料板低速冲击定位系统。首先,利用归一化互相关方法提取基于冲击位置的信号特征,并有效去除传感器的温度交叉敏感和冲击能量影响因素;然后,计算样本信号和待定信号的归一化互相关值,并进行比较;最后,选择待定位信号角度范围内前三个最大相关值的样本点组成定位参考区域,以三角区域质心来评估冲击位置。在600 mm×600复合材料层合板上进行单传感器低速冲击定位验证实验,结果表明利用该定位方法可以准确进行冲击定位,其中最大误差为45.91 mm,平均误差为24.99 mm。通过单传感器定位性能实验结果显示:单传感器位置变化不会影响平均误差范围变化;单传感器定位平均误差和最大误差等大于双传感器,但均符合工程应用范围。结果证明,此方法能够在保证监测准确率的情况下尽可能减少大型复合材料结构传感网络中传感器的数目,同时大大减小布线和数据处理的复杂性,为大型结构健康监测提供了依据。更多还原

【Abstract】 Aiming at the difficulties of getting priori knowledge of composite structure and the redundancy of multisensor dynamic monitoring,a single-sensor impact localization method based on normalized cross-correlation is proposed and a low velocity localization system of composite laminates with single-sensor is built. Firstly,the signal features of impact positions were extracted,the sensor temperature cross sensitivity and impact energy influence factors were removed effectively by using normalized cross-correlation method. Then,the normalized cross-correlation values of sample signals and undetermined signals were calculated and compared. Finally,the sample points of the first three correlation values within the range of the undetermined signal were selected to form the localization reference area and the impact position were estimated by the center of the triangle area. A single-sensor low velocity impact localization experiment was conducted on a 600 mm×600 mm composite laminate. The experimental results showed that the proposed method could localize impact position accurately,the maximum error was 45.91 mm,the average error was 24. 99 mm. The single-sensor localization experiment results showed that the position changes of single sensor would not affect the average error range,the average and maximum errors of single-sensor localization results were larger than dual-sensor,but met the engineering application requirements. The results show that this method can reduce the number of sensors in the sensing network of large composite structures as much as possible while ensuring the monitoring accuracy,and greatly reduce the complexity of wiring and data processing,and provide a basis for health monitoring of large composite structures.更多还原