时变环境与损伤耦合下桥梁结构频率及阻尼比的统计分析

Cable bridge modal parameter statistical analysis under the time varying environment coupled with damage

对时变环境与损伤耦合下我国某斜拉桥的结构频率及阻尼比进行统计分析,以提高结构损伤识别的精度。首先,利用该桥的长期监测数据,采用环境激励技术结合特征系统实现算法识别该桥梁结构的频率及阻尼比;其次,利用人工神经网络算法建立该桥梁结构的环境温度与结构频率及阻尼比的关系模型;然后,通过统计分析,建立完好状态下该桥梁结构模态参数误差因子的概率分布模型;最后,通过分析不同时段与完好结构状态下该桥梁结构模态参数误差因子的相交概率比识别结构损伤,并利用该桥的实测结果验证所提算法的有效性。

Statistical analysis for modal frequencies and damping ratios of a cable-stayed bridge is performed accounting for the coupled effects of time varying environment and damage.Firstly,ERA combined NExT method is utilized to identify structural frequency and damping ratio.Than,BP neural network is employed to establish the relationship between temperature and structural modal parameters using long-term monitoring data.And then,the probability model of variation in structural modal parameter by temperature and noise is obtained.Finally,structure damage is identified by comparing the intersection probability ratio of modal parameter.The proposed approach in this study is verified.