中文摘要：

复合材料结构在外部撞击载荷作用下容易产生目不可检的损伤。进而导致结构承载能力降低。以复合材料加筋圆筒结构为对象，研究基于系统辨识模型的外部低速撞击识别实验的两个关键问题。首先。通过数据分析阐明和完善了系统辨识方法中传递函数的模型阶次选择原则；其次，针对压电传感器生产工艺和安装工艺难以保证各传感器均一性问题。提出了一种传感器信号修正方法，以提高载荷识别精度；最后，分析和讨论了加筋结构型式对撞击识别的影响。实验结果表明，本文所提方法能有效地提高识别和重构外部撞击载荷。

英文摘要：

When composites structures are impacted by an external low-velocity objeet, the subsurface damage would oceur, which is often undetectable by visual inspection. These damages will reduce the structural bearing capacity. In this paper, an experimental study is carried out for a cylindrical stiffened composite structure to investigate several key issues related with the impact load identification based on the system identification method. Firstly, the selection principle of the model order of the transfer function is employed to improve the performance. To overcome the limitation that the homogeneity of sensor responses is not ensured due to the manufacturing and installation process of the piezoelectric sensors, a sensor signal correction method is proposed to improve the accuracy of the force identification. The influence of the stiffeners on the impact identification techniques is analyzed and discussed. The experimental results indicate that the method can improve the identification and the reconstruction of the external discrete impact force on the cylindrical stiffened composite structures.