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采用杆端塑性铰模型、动力弹塑性分析法和静力弹塑性分析法对国家体育场大跨度钢结构罕遇地震作用下的性能进行了分析。三维动力弹塑性分析的输入包括4组地震记录和1组人工地震波;静力弹塑性分析包括单向、双向和三向推覆共12种工况。结果表明,罕遇地震作用下,国家体育场大跨度钢结构最大位移小于其限值;主结构的塑性铰主要出现在桁架柱,数量很少,且屈服程度较轻;次结构的塑性铰数量少,极少数铰的强度下降至残余强度;结构的整体刚度没有下降,承载能力未达到最大。国家体育场大跨度钢结构设计达到了预定的抗震设防性能目标。对静力和动力弹塑性分析两种方法的结果进行了比较,探讨了静力弹塑性分析合适的加载模式,为大跨度钢结构的静力弹塑性分析提供了参考。 相似文献
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江阴某住宅建筑高度为140.95m,属于B级高度建筑,高宽比超限;采用剪力墙结构体系,属于超限高层建筑。针对结构超限情况,工程设计人员采用PKPM和MIDAS两种不同软件对工程建筑结构进行了多遇地震计算,采用PKPM软件进行多遇地震下弹性时程分析,同时还利用PUSH&EPDA软件对结构进行了罕遇地震静力弹塑性分析。分析结果表明,结构各项计算指标均满足规范要求,结构整体设计能达到预期的抗震性能目标,并针对结构超限采取了加强措施,以提高其结构承载能力和延性。 相似文献
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《空间结构》2015,(4)
通过对不同跨度、不同长度、不同支承形式以及不同厚度的三心圆柱面网壳进行数值计算,考察其在设防烈度及罕遇地震作用下的弹塑性动力响应特点.所有柱面网壳模型的杆件截面均根据非抗震设计工况满应力优化设计确定,并满足多遇地震作用的验算.通过对杆件进行单元细分并引入初始缺陷以有效模拟压杆的失稳.由规范反应谱生成三向人工波,采用非线性时程法计算网壳的弹塑性响应.基于计算结果,统计了7度、8度中震及大震作用下的结构塑性变形发展特点和塑性杆件分布区域.研究表明:网壳长度、跨度和厚度的改变会使结构出现较大的弹塑性响应差异;仅满足小震验算的三心圆柱面网壳在中震和大震作用下可能会失效,且失效结构的薄弱位置主要位于距支座1/4跨度的区域;网壳从薄弱区域杆件出现塑性应变到整体结构失效的时间间隔很短.为满足"三水准"的抗震设防目标,建议三心圆柱面网壳的抗震设计进行中震及大震验算. 相似文献
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考虑到网壳结构在实际使用下受自然侵蚀和人工二次施工的影响,将无法按设计预期情况使用的杆件作为失效杆件进行处理,对具有失效杆件的网壳结构进行静力分析和屈曲分析,得出失效杆件靠近网壳中心顶点较为不利,而靠近边部影响微小的定性结论,并且矢跨比过小也会对其不利影响具有放大的作用。此外,高阶屈曲模态受杆件失效的影响较低阶更小,当阶数足够高时,失效所带来的影响可忽略不计。 相似文献
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《Thin》2012
For the cylindrical reticulated mega-structure, two types of cable-strut arrangements are presented. The basic static properties of the pretensioned reticulated mega-structures with different types of cable-strut arrangements are compared and the optimal one is then selected. The elastic static property and stability of the structure with the optimal cable-strut arrangement is comprehensively analyzed. And the indexes including the decrease in structural displacement, reduction in horizontal support reactions, uniformity of distribution of member forces, and the improvement of structural stability are compared with those of the corresponding non-pretensioned reticulated mega-structure. Also, the effect of values and distribution of the cable pretensions on structural stability is studied, and the influence of half-span loading on structural stability is investigated. Results indicate that the static properties and stability of the structure can be most effectively improved for adoption of the crossover arrangement of the cables and struts according to the buckling shape of the non-pretensioned structure. Additionally, the ultimate load-carrying capacity of the structure with small ratio of rise to span can be more effectively improved when the pretension of the cables set in the mid-span is larger than that of the cables set on both sides of the structure. 相似文献
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为了解水平地震作用下具有不同失效机制的单层球面网壳结构在静力荷载作用下的弹塑性稳定性能,利用有限元软件ANSYS,对两个矢跨比为1/2的单层球面网壳结构试验模型进行双重非线性全过程分析,获得结构的弹塑性极限承载力,比较二者的失稳模态,初步了解二者之间的差异。考察结构杆件屈曲、初始缺陷等因素对结构稳定性能的影响,并分析各因素对结构极限承载力的影响规律。结果表明,地震作用下,具有强度破坏特征的网壳结构在静力下的失稳模式表现为结构的整体失稳,而发生动力失稳破坏的结构则表现为局部失稳破坏。杆件失稳和初始缺陷使结构的临界荷载大幅度降低,且地震作用下属于强度破坏的单层球面网壳结构在静力下对初始缺陷的敏感性大于动力失稳破坏结构。 相似文献
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以某大跨度非规则单层网壳为研究背景,应用ANSYS通用有限元分析软件对网壳结构进行了建模并重点模拟了风荷载、雪荷载、温度效应等多种非对称荷载作用,进行了静力分析、特征值屈曲分析以及非线性稳定分析。得到了网壳结构在15种典型荷载组合下的内力、位移结果,分析了非对称荷载对网壳结构静力性能的影响;考虑了几何非线性、材料非线性、初始缺陷,得到了网壳结构在非对称荷载作用下的稳定系数,分析了非对称荷载对网壳结构稳定性能的影响。强调指出非对称荷载作用在大跨度单层网壳结构设计中的重要性,为大跨度非规则单层网壳设计提供参考。 相似文献
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考虑杆件失稳影响的网壳结构稳定性研究 总被引:1,自引:0,他引:1
为了解和掌握杆件失稳对网壳稳定性的影响,指出判别网壳结构杆件失稳的关键问题并提出杆件失稳的判别方法。采用有限元软件ANSYS及自编的前后处理程序对已有网壳试验进行对比分析,得到模型结构的全过程响应、杆件失稳的判断结果和杆件失稳对结构的影响,分析结果符合已有试验结果。并以Kiewitt8型球面网壳为例,分析网壳结构杆件失稳特征及在网壳结构中的传播规律。同时,在考虑杆件稳定性的基础上,考察材料非线性、初始几何缺陷以及杆件挠曲二阶效应和挠曲失稳对杆件稳定性和网壳稳定性的影响规律。结果表明提出的方法可以有效地判断网壳结构杆件的稳定性,杆件失稳及其传播将直接影响结构稳定性。 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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介绍了网壳结构的发展和特点,分析了网壳结构的计算方法,基于大型有限元软件ANSYS对单层网壳进行了屈曲分析,给出了具体结论,为工程结构设计与监测提供了理论依据。 相似文献
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For the cylindrical intersecting-latticed-three-dimensional-beams-system (ILTDBS) reticulated mega-structure with double-layer plane-plate grid substructures, the configuration, form parameters, the support styles of the main structure, and the support ways of the substructures on the main structure are analyzed firstly in this paper. Then the geometrically nonlinear mechanical model and corresponding stability analysis procedure are developed, and the structural stability including buckling modes, ultimate loads under different kinds of conditions and a series of parametric analyses are researched. Moreover, the general failure conditions of the structure are discussed. Finally the basic static properties of the structure are investigated, and a series of parametric analyses with respect to static properties of the structure are performed. All this work will provide theoretical guidance to the actual engineering application of this structure. 相似文献