索杆张力结构的预张力偏差和刚度解析

发布时间：2018-06-15 20:44

本文选题：索杆张力结构 + 预张力偏差　；参考：《浙江大学》2014年博士论文

【摘要】：本文以索杆张力结构为研究对象,重点对其预张力偏差的定量估计和控制、刚度解析问题进行了讨论,主要工作包括以下五个方面： (1)对结构的最不利预张力偏差问题进行了研究。以构件绝对和相对预张力偏差平方和作为衡量结构预张力偏差的指标,利用二次型矩阵Rayleigh商的极性对结构预张力偏差的有界性进行了证明。通过对该二次型矩阵进行谱分解并利用其特征值快速衰减的性质,建立了仅采用该矩阵的低阶特征值和特征向量来近似求解结构最不利预张力偏差及对应的索长误差分布的方法。 (2)以控制结构预张力偏差为目标讨论了主动张拉索的优选问题。将单元的绝对预张力偏差平方和作为表征结构预张力偏差的定量指标,从特征值的角度解释了不同张拉方案对结构预张力偏差控制效果不同的原因。以灵敏度矩阵的第一阶特征值为评价指标,从控制结构整体最不利预张力偏差的角度基于遗传算法提出了一种主动张拉索的优选方法。 (3)结合乐清市体育场月牙形索桁张力罩棚结构工程,从预张力偏差的角度开展了施工张拉方案的比选和结构预张力的实测工作。对该结构在不同张拉控制方案下的结构预张力偏差进行了分析,并建议了可行的预张力施工方案。介绍了该结构的预张力监测方案,并将FBG和EM两种索力测量方法应用于该结构的预张力监测并建立了适应长期运行的实时索力监测系统。分析了该结构张拉过程及初始态的实测预张力特点。 (4)重点对单元刚度与结构需求刚度间的关系进行了研究。给出了一个新的结构切线刚度矩阵按单元组集的表达式,其中结构的弹性刚度矩阵和几何刚度矩阵均可表示成为刚度值和方向向量构成的解析形式。在理论上找到了两个重要的结构自由度子空间,零弹性刚度子空间和需求刚度子空间,零弹性刚度子空间的刚度主要由结构的几何刚度提供,需求刚度子空间的刚度为外荷载作用方向的结构刚度。建立了结构和单元刚度对需求刚度和零弹性刚度子空间刚度贡献度的量化方法,通过该方法可找到结构的关键刚度路径。 (5)对结构的动力刚度特性进行了初步探讨。建立了结构基本模态参数(频率和振型)与单元弹性刚度和几何刚度之间的关系。发现索杆张力结构的频谱视几何刚度和弹性刚度对各阶频率贡献度大小的不同存在明显的“分区现象”,并给出了定量判别结构各阶频率中几何刚度、弹性刚度贡献度的方法。利用零弹性模态子空间的刚度主要由几何刚度提供的特点,根据单元几何刚度对其刚度贡献度的大小建立了一个寻找结构关键预张力单元的方法。最后建立了频率、振型与结构预张力间的解析关系,借助该关系式可根据实测的模态参数来求解结构预张力。
[Abstract]:In this paper, the quantitative estimation and control of the pre-tension deviation and the analysis of the stiffness of the cable-bar tension structure are discussed. The main work includes the following five aspects: 1) the most unfavorable pretension deviation of the structure is studied. Based on the square sum of absolute and relative pretension deviations of structures, the boundedness of structural pretension deviations is proved by using the polarity of quadratic matrix Rayleigh quotient. By using the spectral decomposition of the quadratic matrix and the property of fast attenuation of its eigenvalue, A method of approximate solving the most unfavorable pretension deviation and the corresponding cable length error distribution by using the lower order eigenvalue and eigenvector of the matrix is established. Optimal selection of active tension cables. The square sum of absolute pretension deviation of elements is taken as a quantitative index to characterize the pretension deviation of structure. The reason why different tensioning schemes have different control effects on structural pretension deviation is explained from the point of view of eigenvalue. The first order eigenvalue of the sensitivity matrix is taken as the evaluation index. From the point of view of the most unfavorable pretension deviation of the whole control structure, based on genetic algorithm, an optimal selection method of active tension cable is proposed. From the angle of pretension deviation, the comparison and selection of construction tensioning scheme and the measurement of structural pretension are carried out. The pretension deviation of the structure under different tensioning control schemes is analyzed and the feasible pretension construction scheme is suggested. This paper introduces the pre-tension monitoring scheme of the structure, and applies two cable force measurement methods, FBG and EM, to the pre-tension monitoring of the structure and establishes a real-time cable force monitoring system suitable for long-term operation. The characteristics of the tensile process and the measured pretension in the initial state of the structure are analyzed. The relationship between the element stiffness and the required stiffness of the structure is studied. In this paper, a new expression of tangent stiffness matrix is given, in which the elastic stiffness matrix and geometric stiffness matrix of the structure can be expressed as the analytical form of stiffness value and direction vector. Two important structural freedom subspaces, zero elastic stiffness subspace and required stiffness subspace, are found theoretically. The stiffness of zero elastic stiffness subspace is mainly provided by the geometric stiffness of the structure. The stiffness of the required stiffness subspace is the structural stiffness in the direction of external load. A quantitative method for the contribution of structure and element stiffness to the required stiffness and the subspace stiffness of zero elastic stiffness is established, by which the key stiffness path of the structure can be found. (5) the dynamic stiffness characteristics of the structure are preliminarily discussed. The relationship between the basic modal parameters (frequency and mode shape) of the structure and the elastic and geometric stiffness of the element is established. It is found that the frequency spectrum apparent geometric stiffness and elastic stiffness of cable-bar tension structure have obvious "zoning phenomenon", and the method of quantitatively judging the contribution of geometric stiffness and elastic stiffness to each order frequency of the structure is given. Based on the fact that the stiffness of zero elastic mode subspace is mainly provided by geometric stiffness, a method for finding the key pretension element of structure is established according to the contribution of geometric stiffness to the stiffness of the element. Finally, an analytical relationship between the frequency, mode shape and pre-tension of the structure is established, by which the pre-tension of the structure can be solved according to the measured modal parameters.
【学位授予单位】：浙江大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TU399

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