悬索桥有限元模型修正与吊索全寿命周期内安全性能评估

发布时间：2018-04-10 09:53

本文选题：吊索　切入点：模型试验　出处：《昆明理工大学》2016年硕士论文

【摘要】：吊索在运营期间的安全是悬索桥结构安全的最重要条件之一。相对于悬索桥的建造速度和规模,对吊索损伤的研究还相对滞后,至今还没有形成系统针对吊索损伤机理分析、损伤识别、及安全性能评估的研究方法。本文主要是以吊索损伤和损伤后吊索的安全性为研究对象,围绕吊索的损伤识别和吊索退化模型及安全性分析展开讨论,采用实验模型和仿真分析相结合的研究方法,对吊索损伤后引起的悬索桥静动力特性的影响进行了研究,利用有限元软件对吊索的损伤识别进行了仿真分析,创建了吊索的退化模型并对损伤后的吊索进行了安全性能评估。为了完成上述任务,拟进行一下几方面的研究：1.为了更加准确的进行损伤识别研究,需要一个比较精确的有限元模型,因此,本文对悬索桥有限元模型的修正进行了研究。通过结构参数灵敏度的不同,选择了不同的修正参数,采用优化算法对有限元模型进行了多次修正。将修正后的模型与实桥模型的参数进行比较,证明了悬索桥有限元模型修正过的可行性。修正后的有限元模型能够更加精准的反映模型桥的动静力响应,能更好的为结构损伤识别服务。2.通过对吊索损伤前后悬索桥结构振动模态的分析,开展了基于吊索动力特性指标——结构频率和振型的快速识别方法的研究,基于模态振型Y坐标变化率的加权积的变化来快速判断吊索的损伤位置以及损伤程度,在理论研究的基础上采用有限元仿真模拟验证了损伤识别方法的可靠性。3.以马鞍山左汊悬索桥为工程实例,根据模型的相似理论创建了缩尺比例为1：80的悬索桥实验室模型。并在建好的实验室模型上进行了相应的静力试验和振动试验,测试了不同工况下实验模型的动静力响应,并与有限元软件和实桥测试的数据进行了比较,验证了模型试验的有效性,为桥梁的损伤识别以及桥梁的健康监测打好了基础。4.首先研究了吊索退化的四个阶段退化机理,与退化时间计算公式,并将退化程度与抗力折减系数建立理论关系,然后讨论了考虑丹尼尔效应的吊索断丝后的安全性分析方法,最后以马鞍山大桥左汊主桥的吊索为算例,进行了吊索退化时间的理论计算及吊索退化后的安全性计算。该方法是纯理论计算,与实际工程数据有一定误差,如果与实际监测数据相结合,进行参数修正后使用,便可大大提高预防性养护策略的科学性。
[Abstract]:The safety of sling is one of the most important conditions for structural safety of suspension bridge.Compared with the construction speed and scale of the suspension bridge, the research on the sling damage is still relatively lagging behind. So far, there is no systematic research method to analyze the damage mechanism, identify the damage, and evaluate the safety performance of the suspension bridge.In this paper, the damage of sling and the safety of sling after damage are studied. The damage identification, degradation model and safety analysis of sling are discussed, and the experimental model is combined with simulation analysis.The influence of the static and dynamic characteristics of the suspension bridge caused by the slings damage is studied. The damage identification of the sling is simulated and analyzed by using finite element software. The degradation model of the sling is established and the safety performance of the damaged sling is evaluated.In order to accomplish the above task, I would like to carry out a few aspects of research: 1.In order to study damage identification more accurately, a more accurate finite element model is needed. Therefore, the modification of the finite element model of suspension bridge is studied in this paper.According to the different sensitivity of structural parameters, different modified parameters are selected, and the finite element model is modified many times by optimization algorithm.The parameters of the modified model and the real bridge model are compared, and the feasibility of the modified finite element model of the suspension bridge is proved.The modified finite element model can more accurately reflect the dynamic and dynamic response of the model bridge, and can better serve for structural damage identification.By analyzing the vibration modes of the suspension bridge before and after the sling damage, the fast identification method of the structure frequency and vibration mode based on the dynamic characteristic index of the sling is studied.Taking the left branch suspension bridge in Ma'anshan as an engineering example, a laboratory model of suspension bridge with a scale of 1:80 is established according to the similarity theory of the model.The static test and vibration test were carried out on the established laboratory model. The dynamic and dynamic responses of the model under different working conditions were tested, and the results were compared with the finite element software and the real bridge test data.The validity of the model test is verified and the foundation for bridge damage identification and health monitoring is established.Firstly, the degradation mechanism of four stages of sling degradation is studied, and the formula of degradation time is calculated, and the theoretical relation between degradation degree and resistance reduction coefficient is established, and then the safety analysis method of sling after wire breaking considering Daniel effect is discussed.Finally, taking the sling of the left branch main bridge of Ma'anshan Bridge as an example, the theoretical calculation of the degradation time of the slings and the calculation of the safety of the sling after degradation are carried out.The method is purely theoretical and has some errors with the actual engineering data. If the method is combined with the actual monitoring data and used after parameter modification, the scientific nature of preventive maintenance strategy can be greatly improved.
【学位授予单位】：昆明理工大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：U448.25

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