Kiewitt型索穹顶结构的静力性能与风振响应分析

发布时间：2018-05-25 14:04

本文选题：Kiewitt型索穹顶 + 节点平衡理论　；参考：《华南理工大学》2013年硕士论文

【摘要】：Kiewitt型索穹顶结构是由拉索和压杆组成且依靠施加预应力提供刚度的柔性结构体系，是一种受力合理效率极高的结构形式。该结构的自振频率较低，属于风敏感结构。目前国内对该结构风振响应的研究比较少，因此研究索穹顶结构的风振响应具有重要意义。本文建立了一个跨度为120m的圆形Kiewitt型索穹顶结构，运用节点平衡理论分析结构的超静定次数和初始预应力分布规律，并给出了四组可行初始预应力。对结构进行了无自重作用和考虑自重作用下的形态分析，并与理想的初始预应力进行了对比，结果表明，在结构形态分析时不考虑自重影响会引起较大的误差。分析了结构在满跨活载和半跨活载作用下的静力性能，采用非线性规划法、以初应变能最小为优化目标进行了预应力优化分析。采用非线性有限元法求解了结构在满跨活荷载和半跨活荷载作用下的极限承载力，，得到了结构索松弛的部位和数目，研究表明结构在半跨活荷载作用下的极限承载力是全跨活荷载时的4.05倍。在结构自振特性分析和静风响应分析的基础上，通过计算高阶模态与低阶模态的模态相关系数，初步选取17阶高阶模态作为结构风振响应分析的高阶主要贡献模态。通过引入累积模态参与系数判断选取高阶主要贡献模态方法的合理性，从而构造了结构风振响应分析中的主要参振模态。分别采用CQC法和虚拟激励法对结构进行了风振响应分析，并分别计算分析了5种风速谱和3种空间相干函数下结构的风振响应，结果表明前5阶模态对结构风振响应的贡献较大，多模态参与结构振动，不同节点的风振响应不完全同步，且高阶模态对结构风振响应的影响不可忽略，虚拟激励法能有效的提高结构风振响应计算的效率。根据计算结果，将结构分成四个区域，给出了不同区域位移风振系数的建议值。
[Abstract]:Kiewitt cable dome is a flexible structure system which is composed of cable and compression bar and is provided with stiffness by applying prestressing force. It is a kind of structure with high reasonable force efficiency. The natural frequency of the structure is low and belongs to the wind-sensitive structure. At present, there are few researches on the wind-induced vibration response of the structure in China, so it is of great significance to study the wind-induced vibration response of the cable dome structure. In this paper, a circular Kiewitt cable dome structure with a span of 120m is established. The indeterminate times and initial prestress distribution of the structure are analyzed by using the theory of node equilibrium, and four groups of feasible initial prestress are given. The shape analysis of the structure without and under the action of self-weight is carried out and compared with the ideal initial prestress. The results show that the failure to consider the influence of self-weight in the analysis of the structure shape will lead to great errors. The static behavior of the structure under full span live load and half span live load is analyzed. Using nonlinear programming method and taking the minimum initial strain energy as the optimization objective, the prestress optimization analysis is carried out. The nonlinear finite element method is used to solve the ultimate bearing capacity of the structure under full span live load and half span live load. The results show that the ultimate bearing capacity of the structure under the action of half span live load is 4.05 times higher than that under full span live load. Based on the analysis of the natural vibration characteristics of the structure and the static wind response analysis, by calculating the modal correlation coefficient between the high order mode and the low order mode, the 17th order high order mode is selected as the main high order contribution mode of the wind vibration response analysis of the structure. By introducing the cumulative modal participation coefficient to determine the rationality of the selection of higher order main contribution modes, the main parametric modes in the wind-induced vibration response analysis of structures are constructed. The wind-induced responses of the structures are analyzed by CQC method and virtual excitation method, and the wind-induced responses of the structures under five wind velocity spectra and three spatial coherence functions are calculated and analyzed respectively. The results show that the first five modes contribute greatly to the wind-induced vibration response of the structure, and the multi-modal mode participates in the structural vibration, the wind-induced vibration response of different nodes is not fully synchronized, and the influence of the higher-order modes on the wind-induced vibration response of the structure cannot be ignored. Virtual excitation method can effectively improve the efficiency of wind vibration response calculation. According to the calculated results, the structure is divided into four regions, and the suggested values of the displacement wind-induced vibration coefficients in different regions are given.
【学位授予单位】：华南理工大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TU399;TU352.2

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