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Dynamic Responses of Long-Span Transmission Tower-Line System Subjected to Broken Wires 总被引:1,自引:0,他引:1
A macroscopic finite element modeling approach was proposed to calculate the vibration of a tower-line system subjected to broken wires with software ANSYS/LS-DYNA. In the finite element model, not only the nonlinearity of wires and suspension insulators are considered, but also the support towers are included. The incremental and iterative approaches are combined by applying the unbalanced loads incrementally during each iteration cycle. The approach was illustrated with an example of a Hanjiang-River long-span transmission line system subjected to a shield wire and a conductor failure, respectively. The analysis results showed that the proposed dynamic simulation approach can demonstrate the kinetic process of the tower-line system subjected to wire ruptures: The frequencies of line components were lower and densely distributed, but the frequencies of tower components were higher and sparsely distributed. Anyhow, the dynamic effects of wire ruptures on tower-line system could not be ignored in analysis of tower-line system subjected wire failures. 相似文献
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By combining the time-history response analysis and the eigenvalue buckling analysis,this paper developed a computational procedure to study the elastic dynamic stability of a transmission tower by APDL language in ANSYS.The influences of different input directions of seismic excitations and damping ratio on the elastic dynamic stability of tower were discussed.The following conclusions were obtained:(1) Longitudinal direction of the transmission lines is the worst input direction of seismic excitation for the transmission tower.(2) Dead load has no significant effect on the critical load and the occurrence time of buckling.(3) Vertical input of seismic excitations has no great effect on the dynamic stability of the transmission tower.(4) Damping effect has an influence on the dynamic stability of the transmission tower; however,the inherent characteristics of dynamic buckling is not changed. 相似文献
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以某钢桁拱桥的吊杆的风致振动为工程背景,研究了拱桥常用的吊杆类型,分析了雷诺数Re、斯托劳哈尔数Sr、吊杆结构振动因子λl及吊杆的结构动力特性对钢桁拱桥吊杆振动的影响程度,给出了用吊杆结构振动因子λl和雷诺数Re相结合的判别吊杆是否发生涡激共振的方法,所得的结论与实际桥梁涡激共振现象一致.提出的方法可用于对钢桁拱桥吊杆的风致振动的判别. 相似文献
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Seismic Responses of Asymmetric Base-Isolated Structures under Near-Fault Ground Motion 总被引:1,自引:0,他引:1
An inter-story shear model of asymmetric base-isolated structures incorporating deformation of each isolation bearing was built, and a method to simultaneously simulate bi-directional near-fault and far-field ground motions was proposed. A comparative study on the dynamic responses of asymmetric base-isolated structures under near-fault and far-field ground motions were conducted to investigate the effects of eccentricity in the isolation system and in the superstructures, the ratio of the uncoupled torsional to lateral frequency of the superstructure and the pulse period of near-fault ground motions on the nonlinear seismic response of asymmetric base-isolated structures. Numerical results show that eccentricity in the isolation system makes asymmetric base-isolated structure more sensitive to near-fault ground motions, and the pulse period of near-fault ground motions plays an import role in governing the seismic responses of asymmetric base-isolated structures. 相似文献
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用半解析半数值方法计算层状地基上高承台桩基础沉降的难点在于求解地基基本解(荷载和位移之间的关系)及实现其数值计算。地基基本解有2种分析模型:一种是求解土的基本解,然后将其代入基础的有限元控制方程,这种模型得到的地基柔度矩阵很大,数值计算存在困难;另一种是将土和桩视作地基,用基本解表示,它由轴对称有限元法按照桩帽模型和圆筒模型考虑群桩效应求得,然后将地基基本解代入墩台的有限元控制方程并求解,即可得到高承台桩基础的沉降,这种模型得到的地基柔度矩阵元素相当少,适合数值计算。基于轴对称有限元法的半解析半数值方法,无需繁琐的公式推导,极大地减少工作量,计算效率高。算例结果表明,该分析方法和三维有限元法在分析桩的沉降时结果符合很好。 相似文献
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芜湖长江大桥是我国20世纪末修建的跨度最大、规模也最大的公铁两用新型桥梁,由于采用混凝土板与桁梁结构的新结构和整体结点、大断面带肋箱型的钢梁,现行的规范以及国产钢材已不满足设计要求,需要为本桥梁制定专项设计标准和规范,并解决钢材问题.为此本课题对大跨度低塔斜拉桥板桁组合结构,板桁组合结构混凝土桥面板,高性能1 4MnNbq桥梁用钢,焊接标准、焊接材料及焊接工艺,疲劳问题,厚板焊接整体结点制造技术,混凝土板与桁架桥结合,以及主跨312m跨中合龙技术等8大关键技术进行了详尽的研究并付诸实施.文中简介了应用情况及主要创新点. 相似文献
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长江上的4座公路铁路两用桥 总被引:10,自引:3,他引:7
方秦汉 《铁道科学与工程学报》2004,1(1):10-13
介绍了我国铁路桥梁发展的技术政策及其核心问题和中国铁路钢桥发展史上起到里程碑作用的4座铁路公路两用桥,即武汉长江大桥、南京长江大桥、九江长江大桥、芜湖长江大桥,它们是实现铁路钢桥技术政策的具体范例。 相似文献