基于小波包能量的桥梁结构损伤识别指标研究

发布时间：2018-04-24 20:37

本文选题：桥梁 + 损伤识别　；参考：《天津大学》2014年硕士论文

【摘要】：桥梁结构作为交通基础设施中的重要枢纽，一旦出现问题将严重影响交通系统的正常运行。桥梁在使用期间不断受到各种荷载的作用，随着服役时间的增长结构内部会出现损伤积累情况，若长期对此置之不理不予进行及时维护必将导致恶劣事故发生。因此，如何有效识别桥梁结构的早期损伤成为桥梁健康监测领域的重要研究方向。现有的研究手段多通过构造反映结构系统状态的损伤指标来识别损伤。本文基于小波包能量提出了一种新的桥梁损伤识别指标及其损伤识别分析方法，并通过简支梁数值仿真与斜拉桥模型试验对其进行了验证，具体工作如下： 1、通过对已有损伤识别方法与小波分析理论的总结，定义了一种新的基于小波包能量的损伤识别指标（Damage Detection Index，简称DDI），该指标由小波包能量变化率平方和开方而来，同时给出了基于该指标的损伤识别方法，并通过Matlab编程予以实现。实际应用中利用小波包对环境激励下的桥梁结构加速度响应信号进行分析，根据小波包频带能量计算损伤指标，利用损伤指标的峰值进行损伤识别。 2、利用简支梁模型进行数值仿真研究了DDI损伤指标的识别能力。对模型施加随机白噪声荷载模拟环境激励，并设定多种损伤工况、损伤程度与噪声水平。分析表明损伤指标对于不同工况、不同程度的损伤均能有效识别，，且损伤识别效果受到损伤程度与噪声水平的双重影响。 3、利用斜拉桥模型对损伤指标的损伤识别效果进行了验证。对模型设定单一损伤与双损伤两种损伤工况，首先通过对斜拉桥数值模拟得到加速度响应信号，据此对损伤识别效果进行初步观察；然后通过试验测试得到不同工况下斜拉桥的加速度响应信号，经小波包分析得到损伤指标，结果证明本文所提出的基于DDI损伤指标识别方法有效可行。
[Abstract]:As an important hub of traffic infrastructure, bridge structure will seriously affect the normal operation of traffic system once problems occur. The bridge is continuously subjected to various loads during the service period. With the increase of service time there will be damage accumulation in the structure. If it is ignored for a long time and maintenance is not carried out in time it will lead to bad accidents. Therefore, how to effectively identify the early damage of bridge structure has become an important research direction in the field of bridge health monitoring. Most of the existing research methods identify damage by constructing damage indexes that reflect the state of the structure system. In this paper, based on wavelet packet energy, a new damage identification index and its damage identification method are proposed, and verified by numerical simulation of simply supported beam and model test of cable-stayed bridge. The concrete work is as follows: 1. By summarizing the existing damage identification methods and wavelet analysis theory, a new damage identification index based on wavelet packet energy, called damage Detection Index, is defined, which is derived from the square sum of wavelet packet energy change rate. At the same time, the damage identification method based on this index is given and realized by Matlab programming. In practical application, the acceleration response signal of bridge structure under environmental excitation is analyzed by using wavelet packet, damage index is calculated according to the band energy of wavelet packet, and damage identification is carried out by using the peak value of damage index. 2. The identification ability of DDI damage index is studied by numerical simulation with simply supported beam model. Random white noise load is applied to the model to simulate the environmental excitation, and a variety of damage conditions, damage degree and noise level are set. The analysis shows that the damage index can be effectively identified under different working conditions, and the damage recognition effect is affected by the degree of damage and the level of noise. 3. The damage identification effect of the damage index is verified by the cable-stayed bridge model. The single and double damage modes are set for the model. Firstly, the acceleration response signal is obtained by numerical simulation of the cable-stayed bridge, and the effect of damage identification is preliminarily observed. Then the acceleration response signals of cable-stayed bridge under different working conditions are obtained by test and the damage index is obtained by wavelet packet analysis. The results show that the method proposed in this paper based on DDI damage index is effective and feasible.
【学位授予单位】：天津大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U446

【参考文献】