基于受控结构振动响应的控制图损伤识别

DAMAGE IDENTIFICATION USING TIME-DOMAIN RESPONSE OF STRUCTURES UNDER CONTROL AND CONTROL CHARTS

该文推导了时间序列模型的自回归参数对结构单元刚度损伤系数的灵敏度方程,提出了通过合理配置待检测结构的极点,以提高自回归参数灵敏度的新思路。在此基础上提出了一种反馈控制与控制图相结合的损伤识别方法。该方法首先对结构施加反馈控制,合理配置系统极点;然后将受控结构各测点的时域响应进行主成分分析,以第一主成分建立适用阶的时序模型;最后以AR参数建立休哈特控制图,通过自回归参数的统计性变化判断结构是否发生损伤。一悬臂梁结构的数值算例表明:反馈控制提高了自回归参数的灵敏度,在此基础上采用控制图可以在噪声环境下识别较小程度的损伤。

The sensitivities of autoregressive coefficients to element stiffness are deduced for damage detection. It is presented that the sensitivities of autoregressive coefficients to element stiffness can be enhanced by assigning the poles of system under detection internationally, which may improve the accuracy of damage detection. A damage detection method using dynamic response data of structures under control and control charts is proposed in the paper. In the study, the principal component analysis is first carried out on all response time histories of a closed-loop system for data compression. A time series model with a fitting order is then constructed using the fist principal component data. Finally, X-bar control charts are built based on the mean values of autoregressive coefficients. The statically significant change of the control charts are employed to judge the damage occurrence. The efficiency and capability of the proposed method is demonstrated by applying the method to a cantilever beam. Numerical simulations show that the control chart is efficient for the identification of early small damage with measurement noise as the sensitivities of autoregressive coefficients are enhanced by feedback control.