中文摘要：

以加筋复合材料圆筒结构为对象，研究了复合材料结构的外部低速撞击识别问题。采用压电传感器获取发生低速撞击时在结构内产生的应力波信号。针对加筋复合材料结构的撞击位置识别，特别是监测区域边缘的位置识别问题，提出了基于传感器信号功率的两步法来估计撞击位置；撞击载荷的重构采用系统辨识方法，通过分析系统辨识方法中传递函数的模型阶次和相关性系数的关系，提出了模型阶次选择的原则以进一步完善该方法。结果表明：所提出的两步定位法可较好地估计所有监测区域的撞击位置，所改进的系统辨识方法可较好地识别非加筋区域上的撞击位置和撞击载荷时间历程；当撞击点为加筋区域时，由于筋条对应力波传播的复杂影响导致撞击识别误差偏大。

英文摘要：

The external low- velocity impact identification problem was investigated on a cylindrical stiffened composite structure. The piezoelectric sensors were used to obtain the stress wave signals when the structure was impacted by a foreign object with low-velocity. Aiming at the problem that the impact location identification of a stiffened composite structure and especially the location identification when the impact occurring near edges of the monitoring region, a two-step positioning method based on the power of sensor signals was proposed to estimate the impact location. The impact force was reconstructed by the system identification method, furthermore, the relationship between the model order of the transfer function and the correlation coefficients was analyzed and the principle of the model order selection was suggested to supplement this method. The results indicate that the proposed positioning method can estimate impact locations with high precision regardless the impact occurring region, and the improved system-identification method can identify the location and force time history effectively when an impact event doesn＇t occur in the region with stiffener; however, when an impact occurring on the region with stiffener, the impact can not be well identified due to the complex influence of stiffeners on stress wave propagation.