基于频率响应和统计理论的结构损伤识别研究

为了解决测量噪声下的损伤定位和定量识别问题,提出了基于测量位移的两阶段识别方法和基于统计理论的损伤敏感度分析方法。首先利用损伤刚度的改变特性和测量位移来确定损伤指标,再通过损伤指标的相关自由度变化来确定损伤单元,然后利用自由度缩聚的方法推导出损伤程度的定量计算公式。并利用统计理论来分析噪声对识别结果的影响,推导出损伤指标和损伤程度的噪声敏感性计算公式。数值仿真结果表明,基于测量位移的两阶段损伤识别方法不仅可以精确的识别出损伤位置和程度,而且识别效果受测量噪声的影响较小,该方法明显优于直接广义逆法。

Structural Damage Identification Method Based on Frequency Responses and Statistical Theory

In order to identify structural damage locations and extents, a two-stage damage detection method by using measured displacements is presented and the effect of measurement noise on damage detection performance is studied.The damage index of different degree-of-freedoms which is obtained from the stiffness change and the measured displacements, is utilized to localize the damage sites. Then a damage quantification formula is deduced from the system with reduced number of degree-of-freedoms to calculate the damage extents. Moreover, the measurement noise sensitivity formula based on statistical theory is proposed. The simulation results demonstrate that the proposed two-stage method can more perfectly detect damage as compared with other methods, such as the directness generalized inverse method.