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.

When composites structures are impacted by an external low-velocity object, it is easy to cause the subsurface damage yet undetectable by visual inspection. These damages will reduce structural bearing capacity. In this paper, an experimental study was conducted on a cylindrical stiffened composite structure to investigate several key issues on impact load identification based on system identification method. Firstly, the selection principle of the model order of the transfer function was discussed and clarified to improve the performance. Furthermore, to overcome the limitation that the homogeneity of sensor responses is not ensured due to the manufacturing and installation process of piezoelectric sensors, a sensor signal correction method was proposed in order to improve the accuracy of force identification. At last, the influence of stiffeners on the impact identification techniques was analyzed and discussed. The experimental results indicated that the method can be feasible for improving the identification and reconstruction of external discrete impact force on cylindrical stiffened composite structures.