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为提升传统被动黏滞阻尼器(VD)对斜拉索的减振效果,提出一种融合旋转式电涡流阻尼技术与滚珠丝杠两节点惯质单元的电涡流惯质阻尼器(ECIMD)斜拉索减振新方法。首先研制阻尼系数和惯性质量均可调的ECIMD样机,基于力学性能测试结果辨识ECIMD力学模型参数;然后开展ECIMD对模型拉索减振试验,获得ECIMD阻尼系数和惯性质量对拉索前3阶附加模态阻尼比的影响规律;接着采用有限差分法建立考虑拉索垂度、抗弯刚度及边界条件影响的斜拉索-ECIMD系统分析模型,对比分析斜拉索附加模态阻尼比的数值预测与相应试验结果;最后开展ECIMD对斜拉索多模态减振参数优化研究。研究结果表明:ECIMD的等效电涡流阻尼系数随激振频率的增大表现出逐渐降低的趋势,该特征对斜拉索多模态振动控制尤为有利;考虑斜拉索垂度、抗弯刚度影响的两端固接斜拉索-ECIMD系统模型可用于保守预测斜拉索附加模态阻尼比;与VD相比,ECIMD对斜拉索单模态和多模态均具有更好的减振效果。 相似文献
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近几年斜拉索结构在国内大型钢结构屋盖中的应用也越来越广泛。钢屋盖斜拉索结构与其它结构相比有以下优点:通过张拉拉索,在结构中建立有效、合理的预应力场,以平衡部分使用荷载,减少用钢量:为大跨度屋盖梁提供弹性支点,扩大了下部柱距:控制结构变形,提高结构的刚度;外形美观,使结构具有空间感。本文以南京铁路新客站主站房屋盖斜拉索工程为对象,简单介绍钢结构犀面斜拉索安装施工技术。 相似文献
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预张力斜拉索拱结构体系在索拱结构的基础上添加了上部斜拉系统,因此呈现出不同的力学性能。通过对预张力斜拉索拱结构与索拱结构在相同荷载工况作用下,结构的内力、位移和支反力的参数比较分析,得出两者在静力性能的异同。结果表明,预张力斜拉索拱结构的静力性能优于索拱结构。 相似文献
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钢管混凝土拱桥斜拉扣挂吊装施工中,斜拉扣索无应力索长是保证钢管拱圈结构受力合理的关键参数,本文基于斜拉索悬链线理论,提出考虑温度影响的斜拉扣索无应力索长的计算方法,建立已知索端力的拉索特征参数约束方程,并给出求解拉索无应力索长的迭代公式。用该方法计算澜沧江特大桥斜拉扣挂施工中斜拉扣索无应力索长,并与Ernst等效模量法的结果进行对比分析,证明了该方法的可靠性与有效性。 相似文献
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双向网格型单层柱面网壳结构不仅外型美观、各构件布置规则,而且质量轻、采光好。但是随着网壳跨度越来越大,整体稳定性问题也日益突出,因此制约了此类网壳结构在实际工程中的应用。为此,针对双向网格型单层柱面网壳结构,提出了一种新型布索方案,即在双向网格面内布置斜拉索提高结构的面内刚度,在双向网格面外通过撑杆布置横、纵拉索提高结构的面外刚度。首先通过对不同跨度网壳结构的弹塑性分析验证拉索的布置效果,并考虑各种参数变化对结构稳定性的影响,论证了此类网壳结构的合理性和实用性。其次,结合模型的静力试验研究了此类索撑柱面网壳结构的稳定性,论证了拉索布置的合理性。结果表明,采用撑杆和拉索的交错布置后,网壳结构的受力更加合理,其承载能力有了大幅度提高。此类索撑网壳结构为缺陷不敏感结构,但是撑杆长度对结构承载能力的影响很大,对于不同跨度的网壳结构,撑杆的最佳长度有所不同,实际工程中要确保撑杆具有最佳长度。 相似文献
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大连体育馆屋盖采用了弦支穹顶结构,为探索不同张拉方案的优劣及可行性,校核结构数值分析时数值模型和计算结果的准确性,研究结构在施工、设计荷载下的受力特性,对大连体育馆缩尺模型结构进行张拉成形和静力加载试验,结合有限元软件ANSYS对试验进行全过程模拟。结果表明:撑杆的内力和节点位移的试验值与理论值吻合较好,以撑杆内力为张拉控制目标,达到了张拉要求;撑杆顶升成形方法在试验中需进行反复调试,可控性较差,且需要对索进行精确下料,难度高;斜索张拉法可控张拉点较多,且斜索索力相对较小,索力可控性好,成形精度更高,故在施工中建议采用斜索张拉方案;在静力加载试验中,弦支穹顶上部网壳节点的位移、撑杆轴力和杆件应变与荷载基本满足线性关系,表明结构整体竖向刚度在设计荷载范围内未出现弱化,网壳杆件整体应力水平在设计范围内,结构满足设计要求。 相似文献
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对乐清市新体育馆采取的一种新型内外组合张弦网壳结构进行了断索分析.利用自编向量式有限元(VFIFE)程序模拟分析不同位置径向索相继断裂后该结构的内力重分布及节点变位情况,并和ANSYS生死单元法的计算结果进行比较.荷载态静力分析结果检验了向量式有限元程序在进行静力计算的正确性,而断索过程的模拟更展现了该方法在处理结构非线性动力问题的优越性.分析结果表明,内外组合张弦网壳结构在个别径向索发生断裂的情况下尽管稳定性能有所降低,依然能够继续承载,具有较好的抵抗连续破坏的能力.然而在动力效应的影响下,结构响应有一定程度的放大,断索附近的网壳相对容易出现局部失稳.本文工作为该结构的维护检修、拉索更换以及预应力空间结构的抗倒塌设计提供了参考. 相似文献
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A new approach named Cross-Section Method, based on membrane force transfer mechanism, for calculating internal forces of diagonal members in a single-layer reticulated shell is presented in this paper. Relevant problems in the process of calculating the internal force by Cross-Section Method are elaborated, including determination of geometric parameters of a K6 single-layer reticulated shell, establishment of equilibrium equations and analogy methods for calculating stiffness of spring supports. Stiffness matrixes of link members and the overall structure in spherical coordinates are derived based on spatial position of each member in a K6 single-layer reticulated shell. Static experiments under full-span loads and half-span loads with a 1/10 scale model of a K6 single-layer reticulated shell, adopted in a stadium located in Chiping, Shandong, were conducted. A detailed contrast of results obtained through experiments, Cross-Section Method and FEM is presented. The internal force calculated by Cross-Section Method is close to FEM results, thus verifying the membrane force transfer mechanism and applicability of Cross-Section Method in the single-layer reticulated shell. Though experimental errors are inevitable due to corrosion of some members in the model, experimental results show approximately the same tendency. Also, the results suggest that the structural behavior under half-span loads is more unfavorable compared with full-span loads. 相似文献
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In order to understand the influence of member buckling on the stability of reticulated shells, a key problem of how to distinguish the member buckling for reticulated shell structures was pointed out, and judgment methods of member buckling were obtained. Using a Kiewitt-8 dome as an example, the buckling characteristic and propagation rule of member buckling were studied. Meanwhile, a reticulated dome model tested was analyzed and compared by using the finite element software ANSYS. Judgment results of member buckling and the influence of member buckling on the structure were obtained. The judgment results accorded well with the test. Then taking the member buckling into consideration, the effect of material nonlinearity, initial geometrical imperfections, and member size on the stability of the members and the reticulated shell structures were investigated. The results show that the methods adopted can judge the member buckling for reticulated shell structures effectively; the member buckling and its propagation can affect the stability of the structure directly. 相似文献
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