介绍了混沌理论中相空间重构技术,应用到结构损伤检测与健康监测中.以单自由度弹簧振子为例分析了基于相空间拓扑结构变化的损伤检测方法的可行性,结果表明,当弹簧的刚度降低,相空间拓扑结构发生明显变化,表明该检测方法是可行的.利用相空间重构技术,直接将结构动态响应以相空间的形式展开,根据损伤前后相空间拓扑结构的变化,提出了新的损伤因子.为了验证该方法的可行性与可靠性,进行了圆拱结构动态实验并进行损伤识别.实验结果表明,该方法能够成功地识别出圆拱结构的损伤位置及损伤程度,且灵敏度较之常用的动力指纹方法有了很大的提高.该方法只需单个测点就能计算出该点损伤因子的值,可作为结构整体参量来监测结构是否存在损伤以及结构健康状况.
In this paper, the technology of phase space reconstruction in chaotic theory is introduced and applied in the structural damage detection and health monitoring. The feasibility of the damage detection method based on the topology of phase space is analyzed using a 1-demention oscillator. The results indicate that the differences of topology of phase spaces are obvious between the initial system and the damaged ones with changing stiffness. Using the technology of phase space reconstruction in nonlinear chaotic attractor field, the dynamic responses are directly displayed into phase space. Using the changes of phase space topology of intact and damaged responses,a new damage feature is extracted. In order to demonstrate the method,a dynamic experiment on circular arch is designed. The experimental results indicate that this method can successfully identify the location and the quantification of the damage, and the new feature is much more sensitive than signature analysis approaches. This method can calculate the value of the feature using single dynamic response, which can be used in the structural health monitoring as a global damage feature to monitor the existence of damage and the structural health status.