基于小波分析大跨度悬索桥的结构健康监测

Structural Health Monitoring of Long-span Suspension Bridges Using Wavelet Packet Analysis

在土木结构,如大跨度桥梁,在关键岗位局部损坏的使用寿命可能会不断累积,并可能最终导致他们的突然失效。全球基于振动健康的一个核心问题监测方法是寻求一些对结构性损坏敏感的伤害指标。论文提出了一种针对大跨度悬索桥的在线结构健康监测方法,即利用小波变换的方法。该基于利用小波变换的方法是基于结构的环境振动反应的能量变化烂掉的小波分析。这种方法的主要特点是,所提出的小波能量谱有能力检测出由大跨度悬索桥的环境振动测试造成的结构损伤。作为一个示例,小波能量谱为基础的健康监测系统被用于日常环境条件下的润扬大桥悬索桥。该分析表明,环境温度变化对小波能量谱长期影响,而流量的效果在测量桥的小波能量谱载荷呈现出由于非平稳性质的负荷引起的瞬时变化。该状态指示指数性病反映环境温度对动态特性的润扬大桥悬索桥的影响。现场测试表明,该波包能量谱为基础的状态指示指数对于处于激励环境下的大跨度悬索桥的健康监测是一个很好的候选指数。

During the service life of civil engineering structures such as long-span bridges, local damage at key positions may continually accumulate, and may finally result in their sudden failure. One core issue of global vibration-based health monitoring methods is to seek some damage indices that are sensitive to structural damage. This paper proposes an online structural health monitoring method for long-span suspension bridges using wavelet packet transform （WPT）. The WPT-based method is based on the energy variations of structural ambient vibration responses decomposed using wavelet packet analysis. The main feature of this method is that the proposed wavelet packet energy spectrum （WPES）hasthe abilityto detect structural damage from ambient vibration tests of a long-span suspension bridge.As an example application, the WPES-based health monitoring system is used on the Runyang Suspension Bridge under daily environmental conditions. The analysis reveals that changes in environmental temperature have a long-term influence on the WPES, while the effect of traffic loadings on the measured WPES of the bridge presents instantaneous changes because of the nonstationary properties o fthe loading. The condition indication indices VD reflect the influences of environmental temperature on the dynamic properties of the Runyang Suspension Bridge. The field tests demonstrate that the proposed WPES-based condition indication index VD is a good candidate index for health monitoring of long-span suspension bridges under ambient excitations.