共查询到19条相似文献,搜索用时 140 毫秒
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冷弯薄壁槽钢短柱局部屈曲后相关作用的弹塑性分析 总被引:2,自引:0,他引:2
本文建立了大挠度弹塑性有限条法,用以分析冷弯薄壁单轴对称开口截面短柱段局部屈曲后相关作用,得出了一系列对于工程设计有价值的结论。进行了12根槽钢截面短柱段受压试验。通过与前人对单块板的分析及本文试验值的比较,证明本文提出的大挠度弹塑性有限条法具有相当高的精度。 相似文献
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某大跨单层球面网壳结构的非线性屈曲研究 总被引:1,自引:0,他引:1
为研究杆件稳定、初始几何缺陷、几何非线性、材料非线性对某单层球面网壳结构整体稳定性的影响,首先对结构进行线性屈曲分析得到屈曲模态和临界荷载,其次采用弧长法对结构进行非线性屈曲全过程分析,同时确定最不利初始几何缺陷分布模态,最后采用Newton-Raphson法对按此最不利缺陷分布的结构进行弹塑性屈曲全过程分析.计算表明:初始几何缺陷按最低阶屈曲模态分布的一致缺陷模态法可能不适用于大跨单层球面网壳结构的稳定性分析;荷载不对称分布对结构的稳定性更为不利;初始几何缺陷和材料非线性对结构稳定性的影响较大. 相似文献
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本文通过对一榀变截面门式刚架结构稳定承载力的破坏性试验,研究了在工字形构件腹板发生局部屈曲后刚架结构的受力性能及破坏机理,获得了结构全过程加载的荷载-挠度曲线以及构件和节点局部屈曲的发生及扩展情况,指出了梁柱节点设计的重要性及构造要求;应用大挠度弹塑性板壳有限元对变截面门式刚架结构进行了大挠度弹塑性理论分析,研究了腹板和翼缘宽厚比的变化对刚架结构稳定承载力的影响;在弹塑性范围内用梁柱单元对刚架结构的稳定承载力进行了分析和计算,并与板壳单元的计算结果做了比较,发现板壳单元的理论计算结果与试验研究结果相当吻合;理论与试验研究结果对工程设计有一定的参考价值。 相似文献
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本文利用ANSYS程序,在弹塑性、大挠度范围内,建立考虑板件间相关屈曲作用的双坡楔形偏压柱的有限元模型,并模拟实际情况,在模型中引入初始几何缺陷和残余应力,研究几何参数及残余应力对其稳定承载力的影响. 相似文献
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《四川建材》2016,(3):87-88
整体稳定分析问题一直是球面网壳设计中的关键问题。理论分析和工程实践表明:网壳结构的设计通常受其稳定性控制。网壳结构的整体稳定分析主要有三种:屈曲分析、弹性整体稳定分析和弹塑性整体稳定分析。本文借助有限元分析软件ANSYS,以某单层肋环型球面网壳为代表,对其进行屈曲分析、弹性整体稳定分析和弹塑性整体稳定分析,同时深入研究不同缺陷模式对整体稳定性能的影响。研究发现,单层球面网壳前六阶屈曲模态的整体稳定系数相接近,且出现相邻的重模态现象;最低阶屈曲模态缺陷对网壳结构的弹性整体稳定承载力影响最大,但对其弹塑性整体稳定承载力的影响未必最大,故有必要考察相邻的较低阶屈曲模态缺陷对网壳结构的影响。 相似文献
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北京工人体育场钢结构罩棚为周边设置摩擦摆支座的开口单层扁薄拱壳结构。为提升结构整体稳定性,采用考虑结构整体初始缺陷的4等分杆件模型进行有限元模拟,针对拱壳整体形态、构件截面规格和支座刚度共计3类11个参数进行单变量敏感性分析,评估结构在特征值屈曲分析、弹性和弹塑性全过程分析下的受力性能。分析表明:弹性全过程分析临界系数与特征值屈曲分析临界系数间具有强线性相关性,二者比值平均为0.535;结构塑性折减系数平均值为0.418;拱壳整体形态类参数的敏感性相对较高,其中拱端高差敏感性最高;构件截面规格类参数中,拱肋和外环梁截面规格的敏感性较高,支座刚度的敏感性相对较低。提出了结构整体稳定设计流程,结合特征值屈曲敏感性分析结果、构件承载力富余度和弹塑性全过程分析出铰杆件类型进行综合分析,有助于提高结构整体稳定设计效率。 相似文献
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The analysis of submarine pressure hull assumes great importance among structural engineers due to the complexity involved in the collapse mechanism of stiffened shell structures. In most of the cases, the failure of stiffened shell structures occurs due to elastic buckling. But for some combinations of shell-stiffener geometry and material characteristics, the structure can fail by inelastic buckling, for which the methods of analysis are meagre. In this paper, the analysis of submarine pressure hull structure in which the failure gets governed by inelastic buckling is demonstrated. Three different approaches have been employed to investigate the ultimate strength of the ring stiffened submarine pressure hull structure with inelastic buckling modes of failure. The methods used are ‘Johnson–Ostenfeld inelastic correction’, ‘imperfection method’ and ‘finite element approach’. A typical submarine shell structure has been analysed for the inelastic buckling failure using these three approaches and the results are discussed. 相似文献
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本文以九寨沟甘海子国际会展中心展厅结构为工程背景,介绍了单层椭球网壳-组合楼板混合结构的分析设计过程。首先,采用相贯节点的计算理论,对该工程采用的鼓节点的设计进行了详细论述。此外,本文采用子空间迭代法对该混合结构进行了特征值屈曲分析;采用非线性有限元理论,结合N-R法和柱面弧长跟踪技术,对该结构进行了考虑初始缺陷的非线性全过程分析;并采用估算公式进行了校核。计算结果表明,特征值屈曲分析结果是局部失稳的极限荷载,而非线性屈曲分析结果是整体失稳的极限荷载。对于有局部刚度薄弱的结构,采用非线性屈曲分析得到的极限荷载更为合理。 相似文献
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常州市体育馆椭圆抛物面钢屋盖采用由Levy索杆系和单层网壳构成的弦支穹顶结构,与已研究的常规弦支穹顶相比,其具有体量大,矢跨比高和外形为椭圆抛物面的特点。将弦支穹顶与单层网壳进行稳定性对比研究,包括构件屈曲、线性屈曲和几何非线性屈曲等,分析了高矢跨比弦支穹顶中索杆系的作用以及对结构设计起控制作用的破坏形式。研究结果表明,索杆系增加了弦支穹顶的整体性,降低了其对初始几何缺陷的敏感性,但对结构刚度、基本自振周期和模态、构件屈曲荷载、线性屈曲荷载、无初始缺陷的非线性屈曲荷载、屈曲模态等影响不大。高矢跨比弦支穹顶仍对初始缺陷较为敏感,稳定性仍是结构设计控制因素之一。此外,由于椭圆抛物面外形,活荷载布置形式对结构屈曲模态影响较大,且满跨活荷载并不一定是最不利的活荷载布置形式。 相似文献
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金寨影剧院屋盖采用了椭圆抛物面网壳结构.文章对网壳结构进行了结构的动力分析,计算了结构在风荷载作用下的响应,并对网壳结构进行了考虑初始几何缺陷的屈曲分析,得到了结构的极限承载力. 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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The paper presents 3D results of a quasi-static buckling analysis of a funnel-flow cylindrical metal bin composed of horizontally corrugated sheets strengthened by vertical columns. A linear buckling and a non-linear analysis with geometric and material non-linearity were carried out with a perfect and an imperfect real silo shell by taking into account axisymmetric and non-axisymmetric loads imposed by a bulk solid following Eurocode 1 and different initial geometric imperfections and load non-uniformities around the circumference. The calculated buckling forces were compared with the permissible one given by Eurocode 3. 相似文献
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Reliable and accurate method of the experimental buckling prediction of thin-walled cylindrical shell under an eccentric load is presented. The experimental arrangement and specimens are discussed in detail, including the measurement of the geometric imperfections of the specimen's surface using a coordinate measuring machine. Different FE models, in terms of complexity, are used to simulate the experiment arrangement in an attempt to get a good agreement with the experimental buckling loads and study the effect of measured initial geometric imperfections, load eccentricity, load eccentricity position along the shell's circumferential direction and different experimental arrangement that influence the boundary conditions. It has been demonstrated that FE models with simplified rigid support conditions overestimate the prediction of the experimental buckling load even though these models included the effects of the measured initial geometric imperfections and load eccentricity. By contrast, FE models with realistically modeled support conditions achieved the best result. The average deviation −1.59% from the experimental buckling loads was achieved using the FE model simulating the mounting devices as elastic bodies and with surface-to-surface contact interaction behavior on the support. The presented work also demonstrated the strong influence of the eccentric load position along the imperfect shell's circumferential direction on the buckling of the thin-walled shell. 相似文献
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《Thin》2014
In spite of numerous papers in the literature on the buckling behavior of cylindrical shell structures, the effect of local large imperfections caused by physical contacts has not been exhaustively examined yet. To this end, this paper reports on an experimental program on the buckling and post-buckling response of thin cylindrical shells with local dent imperfections under uniform external pressure. The results of this study can be used in practical structures with similar geometric features, i.e. D/t ratio. 相似文献