【作者】 栗燕娜；

【导师】 孙宗光；

【作者基本信息】 大连海事大学 ， 道路与铁道工程， 2006， 硕士

【摘要】 建立有限元模型,对于大型桥梁结构的健康诊断研究是不可缺少的。而高精度、真正三维模型、构件独立描述等是面向健康诊断的有限元模型应具备的基本特性。分析和控制有限元模型误差,从而获得高精度有限元模型,对于成功地实现结构损伤识别和诊断是十分重要的。 本文针对悬索桥结构,虚拟一座总跨度1000m的三跨连续悬索桥。面向健康诊断研究,设计制作了一座总跨度10m的悬索桥缩尺试验模型。同时,根据这一试验模型的设计图纸建立了相应的初始有限元模型。基于试验模型的静力试验和振动试验结果与初始有限元模型计算结果的比较,展开对面向健康诊断的悬索桥有限元建模的模型误差分析。通过调整初始模型的参数,对模型进行静动力分析,与初始模型计算结果对比考察参数改变对模型静动力响应的敏感性,从而为面向健康诊断的有限元建模提出一些有参考价值的建议。 参数敏感性分析中考察的参数包括结构节点刚性区的处理,加劲梁截面面积,主缆线形,主缆初始内力,塔顶鞍座边界条件以及加劲梁和主缆的弹性模量。通过这些参数的误差敏感性分析,得到以下一些主要结论: 1.在悬索桥健康诊断分析中,当主要监测对象为中跨的主缆和吊索时,由于中跨主缆大垂度线形对主梁的控制,有限元模型可对加劲梁做适当简化处理,它对计算的影响相对比较小; 2.对于空缆状态下的主缆线形,采用矢高相等的二次抛物线型还是采用悬链线线型,对悬索桥的静动力行为产生的差异不大; 3.塔顶鞍座与主缆的连接条件对结构的影响非常大,处理不当会使结构系统发生很大变化,导致动力特性及加劲梁相应误差都很大。 4.调整加劲梁弹性模量,对所有振型都有影响且影响较一致,而对主缆弹性模量的调整只对特定振型有影响,并且主缆弹性模量对加劲梁挠度敏感性很大。更多还原

【Abstract】 It is indispensable to establish finite element models for long-span bridges. And high-accuracy, real dimensional model, and separate description of components are basic properties to finite element models for health diagnosis. Analyzing and controlling the error of finite element model to obtain high-accuracy finite element model, it is very important to achieve the identification and diagnosis of structural damage successfully.A span of 1000m and 3-span continuous beam suspension bridge is invented. Then a span of 10m scale test model of suspension bridge has been designed for health diagnosis. Meanwhile, based on design papers of the test model, corresponding finite element model has been established. To compare the results of static and dynamic test with initial finite element model calculations, error analysis of finite element modeling has been developed. With the adjustment of initial model parameters, the static and dynamic analysis of the model, and the comparison of initial model calculations, the sensitivity of static and dynamic responses is examined, and some valuable suggestions are put forward to finite element modeling for health diagnosis.In the sensitivity analysis, examined parameters involve the treatment of nodal stiffness areas, the cross-sectional area of stiffening girder, the main cable curve, the initial inner force of main cable, the boundary conditions and the elastic modulus of girders and cables. By analyzing the error of these parameters, the following conclusions are obtained:1. When the major monitoring objects are main cables and hangers of middle span, the stiffening girder of finite element model can be simplified, and it affects the results little because the girder is controlled by the big sag of span.2. The cable curves at cable finish stage, which utilizes equal rise of the quadric curve or the catenary curve, bring little difference to static and dynamic behaviors of suspension bridges.3. The joint conditions of saddle on tower and cable affect structure much. With improper treatment, it will make the structure great variance and lead to the big error of dynamic properties.4. The affection of all vibration modes is in accordance by adjusting girder elasticmodulus. But the adjustment of cable elastic modulus only influences the specific modes. The cable elastic modulus is sensitive to the girder deflection.更多还原