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基于非线性时程分析理论 ,提出了桅杆结构在动力荷载下的设计方法 ,以保证结构动态下的强度、变形和稳定性符合使用要求。给出并分析了桅杆结构动态设计实例 ,结果表明本方法直观、可靠 ,可应用于工程设计 相似文献
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桅杆结构纤绳与杆身连接拉耳风致疲劳寿命预测 总被引:2,自引:0,他引:2
本文介绍了疲劳断裂力学中的Forman公式及相关控制因素。以一工程实例 ,建立桅杆的空间动力分析模型 ,进行有限元非线性时程动力分析 ,运用Forman公式对桅杆结构纤绳与杆身连接拉耳在随机风荷载作用下的疲劳寿命进行了预测 相似文献
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桅杆结构是一种具有较强几何非线性的结构,风荷载是其主要设计荷载。在对广义脉动风荷载样本模拟的基础上,采用增量形式的非线性有限元模型对桅杆的动力响应进行分析,并进行算例计算,说明提出的方法具有较好的精度。 相似文献
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桅杆结构动力特性分析及试验研究 总被引:2,自引:0,他引:2
通过对桅杆结构中纤绳及杆身的非线性分析,建立了桅杆结构空间自由振动方程,应用子空间迭代法可求得任意个低阶振型和频率。对不同风向及不同纤绳初拉力下桅杆结构的动力特性进行分析,与试验研究比较表明,理论计算结果与试验结果吻合良好。 相似文献
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本文通过对桅杆结构中纤绳及杆身的非线性分析,建立了桅杆结构空间自由振动方程,应用子空间迭代法可求得任意个低阶振型和频率。对不同风向及不同纤绳初拉力下桅杆结构的动力特性进行分析,与试验研究比较表明,理论计算结果与试验结果吻合良好。 相似文献
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桅杆结构非线性稳定与振动的杆索有限元分析法 总被引:5,自引:0,他引:5
本文基于修正的总体Lagrangian坐标描述法推导了空间索、杆单元的大位移刚度矩阵。基于虚功原理推导了索单元的一致质量矩阵。建立了桅杆结构的非线性静、动力增量平衡方程。采用Newton-Raphson迭代法和修正弧长迭代法求解桅杆在失稳前、后的整个变形路径。应用子空间迭代技术求解桅杆结构的任意个低阶振型和周期。根据Wilsons法的增量形式求解桅杆结构在任意动力荷载作用下的时程曲线。算例表明:本文导出的计算公式具有极高的精度。本文给出的方法适应性极强。 相似文献
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研究了桅杆结构的破坏原因和破坏机理,针对桅杆结构本身的结构动力特性和损伤后的动力特性改变,对应用模态分析方法在桅杆结构的损伤诊断的应用问题进行了分析,指出了模态分析的损伤诊断方法在桅杆结构中的应用方向。 相似文献
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Dynamic response of guyed masts 总被引:8,自引:0,他引:8
Murty K.S. Madugula Yohanna M.F. Wahba Gerard R. Monforton 《Engineering Structures》1998,20(12):1097-1101
Natural frequencies of guyed masts were determined by modelling the mast as truss elements in one model and as beam-column elements in another model. Guys were modelled as cable elements in both cases. The natural frequencies from the two models agreed closely with each other. For the purpose of verification of the finite element modelling, two triangular steel latticed scale-modelled guyed masts were fabricated and tested on a shake table specially designed to test guyed masts. The experimental results were in good agreement with the results from the finite element analysis. The finite element modelling was then applied to six existing towers which are representative of the design practices in Canada. Based on the results of these analyses, the influence of ice accretion, guy initial tensions and torsion resistors on the dynamic characteristics of the guyed masts is discussed. 相似文献
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S. Ali Ghafari OskoeiGhyslaine McClure 《Engineering Structures》2011,33(5):1764-1772
Telecommunication structures are essential components of communication and post-disaster networks and critically important facilities require reliable earthquake-resistant design procedures in seismically active regions. Calculation of the nonlinear seismic response of tall guyed masts using detailed time-step finite element methods is far more complex than linear response spectrum analysis that is routinely used in structural engineering practice. It is recognized that detailed computational procedures are not always necessary, in particular when the goal of the analysis is to provide a global earthquake-resistant design check on a regular structure with predictable response: this is when rational simplified methods are called upon to calculate the seismic demand. However, up until now, no such method exists for tall guyed masts that can account for the dynamic cable-mast interactions which dominate seismic effects in these structures. In the study reported here, the writers explore the dynamic behavior of guy cables under harmonic and seismic support ground motion through detailed computational modeling and propose a novel frequency-dependent method to evaluate the equivalent dynamic stiffness of guy clusters. This development will contribute efficiently towards a new robust rational model of general applicability for simplified seismic analysis of tall guyed telecommunication masts.Detailed numerical simulations involving 57 guy cables from eight existing towers with varying heights of 150-607 m were used in the study. A mathematical procedure was developed to replace the nonlinear time-variant cable stiffness with an equivalent linear frequency-dependent spring/mass system, based on the response spectrum of individual guy cables and the frequency content of the seismic excitation. Comparison of the main response indicators of these equivalent models and the detailed nonlinear finite element analysis results confirmed the reasonable and consistent engineering accuracy of the proposed simplified method with considerable savings in analysis effort. 相似文献
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基于频域的桅杆结构风振疲劳分析 总被引:2,自引:0,他引:2
本文基于随机振动理论对实测的桅杆结构风洞试验数据进行处理,分析了桅杆结构风振响应的频谱特性,并且从频域着手通过简单的数值运算求得足够精确的等效应力用于计算桅杆结构的风振疲劳寿命,避免了雨流点法极大的工作量。 相似文献
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推导了弹性结构体系在任意动力荷载作用下的动力稳定性判别准则,用此准则对实际桅杆结构在随机风载下的动力稳定性进行分析,并在总结桅杆结构动力失稳的特性和规律的基础上,提出了简化的位移判别准则。 相似文献
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通过研究与思考,提出了两种适用于张拉索的找形方法,给出了这两种方法的原理与具体实施步骤,并分别以简单索结构和桅杆结构为计算实例进行了验证和比较,有效的解决了桅杆结构的找形问题。 相似文献