江中大跨越输电塔结构撞击反应及其模型试验设计方法

发布时间：2018-03-26 20:16

本文选题：大跨越输电塔　切入点：高桩承台　出处：《南京工业大学》2015年硕士论文

【摘要】：船舶撞击作用是江中、海上大跨越输电塔的重要控制设计荷载之一,目前关于大跨越输电塔结构的撞击反应及其模型试验研究尚处于空白阶段。因此,有必要研究考虑高桩承台与大跨越输电塔共同作用的结构撞击反应特性,分析不同参数对撞击反应的影响,探讨该结构的撞击模型试验设计方法。本文建立了高桩承台-大跨越输电塔的整体有限元模型,分析考察上部塔架与基础共同作用的动力特性及其变化规律。以高桩承台抗侧刚度、撞击速度、撞击质量为参数,对比不同分析模型的结构撞击反应,分析上述参数对结构撞击反应的影响规律。最后,应用量纲分析法推导撞击试验模型的相似条件,设计原型结构和模型结构,并开展相应的撞击反应模拟和对比分析,探讨撞击模型试验设计方法的准确性。本文的主要内容如下：(1)大跨越输电塔结构动力特性分析应用ANSYS/LS-DYNA软件建立大跨越输电塔-高桩承台的整体有限元模型,分析考虑上部塔架与基础共同作用的动力特性；对比了上部杆塔、高桩承台基础及上部塔架-高桩承台基础整体结构的自振特性；探讨高桩承台抗侧、抗扭刚度变化对大跨越输电塔结构自振特性的影响规律。分析结果表明,大跨越输电塔-高桩承台基础的整体结构模型(即考虑上部杆塔与下部基础杆塔作用)的结构自振周期较上部杆塔结构大,且其振动模态与杆塔结构不同；高桩承台基础的抗侧、抗扭刚度越大,则整体结构自振周期越小,当其抗侧、抗扭刚度达到一定值后,结构自振周期变化较小。(2)大跨越输电塔结构撞击反应及其影响因素分析建立质量块撞击下江中大跨越输电塔结构动力反应的有限元模型,分析撞击过程中撞击力时程曲线特性和能量转化特点；考察结构受撞过程中大跨越输电塔在水平方向、竖直方向上变形特征、振幅和周期；对比不同抗侧刚度、撞击速度、撞击块质量时,撞击力和结构的撞击响应。分析结果表明：基础刚度下降时,结构撞击响应增大,撞击响应的周期和振幅均增大；撞击速度增大时,撞击响应周期基本不变,撞击力和撞击响应振幅均线性增大；撞击质量增大时,撞击响应周期基本不变,撞击力和撞击响应振幅与撞击质量的平方根呈线性关系。(3)大跨越输电塔结构撞击模型试验设计方法应用量纲分析法推导了模型设计的动力相似条件和冲击动力相似条件,建立原型结构和模型结构有限元模型,开展结构动力特性和撞击反应分析,将振幅、周期、撞击力等参量的相似比模拟值与理论值对比。分析结果表明：两种相似条件应用于结构动力特性分析时,与理论值均吻合较好；冲击动力相似条件应用于结构撞击反应分析时准确性更好,保证与原型结构的撞击响应周期和幅值相似,适用于大跨越输电塔结构的撞击模型试验设计。
[Abstract]:Ship impact is one of the important control design loads for long span transmission towers in the middle of the river. At present, the research on the impact response and its model test of long span transmission tower structures is still in blank stage. It is necessary to study the impact response characteristics of structure considering the interaction of high pile cap and long span transmission tower, and analyze the influence of different parameters on the impact response. The design method of impact model test for this structure is discussed. In this paper, the integral finite element model of transmission tower with high pile cap and long span is established. The dynamic characteristics of the interaction between the upper tower and the foundation and its variation law are analyzed and investigated. Taking the lateral stiffness, impact velocity and impact mass of the pile cap as parameters, the structural impact responses of different analysis models are compared. The effects of the above parameters on the impact response of the structure are analyzed. Finally, the similar conditions of the impact test model are derived by using the dimensional analysis method, the prototype structure and the model structure are designed, and the corresponding impact response simulation and comparative analysis are carried out. This paper discusses the accuracy of the design method of impact model test. The main contents of this paper are as follows: 1) the structural dynamic characteristics analysis of long span transmission tower using ANSYS/LS-DYNA software to establish the integral finite element model of long span transmission tower and high pile cap. The dynamic characteristics of the upper tower and the foundation are analyzed, the natural vibration characteristics of the upper pole tower, the high pile cap foundation and the upper tower-high pile cap foundation are compared, and the anti-side characteristics of the high pile cap are discussed. The effect of torsional stiffness on the natural vibration characteristics of large span transmission tower structures is studied. The structural natural vibration period of the large span transmission tower with high pile cap foundation (that is, considering the interaction between the upper pole tower and the lower foundation tower) is larger than that of the upper pole tower, and its vibration mode is different from that of the tower structure. The larger the torsional stiffness of the pile cap foundation is, the smaller the natural vibration period of the whole structure is. When the torsional stiffness reaches a certain value, The structural impact response of long span transmission tower and its influencing factors are analyzed. The finite element model of the dynamic response of the transmission tower in the middle of the Yangtze River under mass block impact is established. The characteristics of time-history curve and energy conversion of impact force during impact are analyzed, and the deformation characteristics, amplitude and period of transmission tower with large span in horizontal and vertical direction during the process of structural impact are investigated, and different lateral stiffness and impact velocity are compared. The results show that when the foundation stiffness decreases, the impact response increases, the period and amplitude of the impact response increase, and the impact response period is basically unchanged when the impact velocity increases. When the impact mass increases, the impact response period is basically unchanged. There is a linear relationship between the impact force and impact response amplitude and the square root of the impact mass.) the design method of impact model test for large span transmission tower structures is derived by using dimensional analysis method. The dynamic similarity conditions and impact dynamic similarity conditions of the model design are derived. The finite element model of the prototype structure and the model structure is established, the dynamic characteristics of the structure and the impact response analysis are carried out, the amplitude, the period, The results show that the two similar conditions are in good agreement with the theoretical values when applied to the analysis of the dynamic characteristics of the structure. The impact dynamic similarity condition is more accurate when applied to the impact response analysis of the structure, which ensures that the impact response period and amplitude are similar to those of the prototype structure, and is suitable for the design of the impact model test of the long-span transmission tower structure.
【学位授予单位】：南京工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU347;TU311.3

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