共查询到18条相似文献,搜索用时 171 毫秒
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《建筑钢结构进展》2015,(6)
为了研究钢管混凝土组合框架梁柱半刚性连接的受力性能与破坏形式,本文采用ABAQUS软件建立了钢管混凝土柱与钢-混凝土组合梁端板连接的非线性有限元模型。该模型考虑了材料非线性、几何非线性和复杂接触问题,确定了钢管核心混凝土和楼板混凝土的本构关系模型、各组件的复杂接触关系。研究了组合节点的柱端水平荷载-水平位移关系曲线和破坏形式,并用试验结果验证了计算结果的准确性。进行了大量的参数分析,获得了在正、负弯矩作用下影响组合节点极限承载力和初始刚度的主要参数。研究结果表明:所建立的钢管混凝土柱与钢-混凝土组合梁端板连接的有限元模型具有较好的准确性,可以为半刚性钢管混凝土组合框架的理论研究提供参考依据。 相似文献
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利用有限元软件ABAQUS对方钢管再生混凝土短柱轴压承载力进行非线性分析,建立了适用于有限元分析的钢管和再生混凝土本构关系模型;利用极限平衡法推导方钢管再生混凝土短柱轴压承载力计算公式函数类型;利用计算结果拟合出方钢管再生混凝土短柱轴压承载力的计算公式。研究结果表明:所提出的材料本构关系模型可以较好地满足对方钢管再生混凝土短柱轴压承载力进行模拟分析的要求,通过模拟获得的计算结果与相关试验结果差异较小,所建立的方钢管再生混凝土短柱轴压承载力计算公式能够较准确地计算构件极限承载力。 相似文献
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本文针对常用的斜拉立体桁架两塔柱三跨结构形式,基于UL列式,采用混合有限元,分别按空间(面外自由)和平面(面外自由度约束)两种模型,进行了线性、几何非线性、材料非线性以及同时考虑两种非线性的屈曲分析和比较,得出了结构的极限承载力。研究表明,空间模型比平面模型的安全因子低。线性屈曲和只考虑几何非线性屈曲两种模型的安全因子差别较大,而考虑材料非线性和双重非线性两种模型的安全因子比较接近。几何非线性对斜拉立体桁架的极限承载力影响较小,其结构极限承载力主要由材料非线性控制。立体桁架的塑性部位出现在塔柱附近的腹杆和弦杆,以及跨中附近的弦杆以及拉索附近的弦杆。此外,探讨了塔高、桁架高度、索距以及拉索刚度对结构极限承载力的影响,其中索距对结构的极限承载力影响最大。 相似文献
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采用传统分析方法对悬索桥钢筋混凝土加劲桁架结构进行分析,结果表明在运营荷载作用下构件计算内力普遍存在偏大问题。本文考虑结构几何非线性和材料非线性的影响,提出了该类结构杆件刚度考虑混凝土材料非线性影响的模拟方法,对某悬索桥进行了有限元分析及承载能力检算分析,并将计算分析结果与荷载试验结果进行对比分析,结果表明,运营阶段结构内力计算时,几何非线性效应不明显,考虑混凝土构件开裂对杆件刚度的折减影响,使构件受力状况与实际状况更加吻合。 相似文献
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运用非线性有限元基本理论研究张弦空间结构的非线性特征。针对5个张弦空间结构工程,研究结构的几何非线性、材料非线性和边界条件的状态非线性特征,揭示其基本力学特性。分析表明:张弦空间结构的刚性构件体系贡献了结构的线性刚度,结构的变形协调使拉索应力刚化进而增大结构的几何刚度;对索施加初始预拉力可以增大结构几何刚度,但不影响结构总刚度增量的变化规律;结构总刚度的非线性部分随荷载步的改变而更新,结构分析须先确定结构所处的荷载工况;结构材料进入塑性后表现为结构总切线刚度中线性部分的降低,当结构达到弹塑性极限承载力时表现为结构材料失效。基于张弦结构的自平衡特性,当张弦空间结构滑动支座滑移达到滑程时,结构的边界条件转变为相应的铰支座或弹性支座。通过屋盖结构支座附近同位置且同方向的下部支承结构体系的刚度与屋盖邻支座区域杆件体系刚度的比较,可方便准确地对屋盖单独模型进行屋盖结构在实际工作环境中边界条件的模拟。 相似文献
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Abstract: A methodology for the geometric and material nonlinear analysis of plane steel frames suitable for implementation in a microcomputer or personal computer platform is presented. The proposed procedure takes into consideration both geometric and material nonlinearities in its formulation. Geometric nonlinearity in the form of member and frame instabilities is accounted for by the use of pseudo-joint loads derived from the geometric stiffness matrix of the structure. Material nonlinearity in the form of cross-sectional plastification and progressive member yielding is accounted for by the use of a cross-sectional plastification model and the concept of effective member stiffness. Since both cross-sectional plastification and spread of yield along member length are considered in the analysis, the proposed approach is regarded as a plastic zone model. Unlike conventional plastic zone models in which intensive computations are required to obtain solutions, the proposed model employs simplified procedures by which spread of plasticity in the structural frame is accounted for in an approximate manner. Despite its simplicity, the proposed model gives reasonably accurate results when compared with other more rigorous approaches. To verify the applicability of the approach in predicting inelastic frame behavior, the proposed method was used to analyze a variety of frame structures. The results, expressed in terms of load-deflection responses, member forces, and moments, compared well with those obtained using other more elaborate inelastic analysis methods. 相似文献
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针对目前拱桥非线性研究现状,对钢管混凝土劲性骨架拱桥改变其参数的1 000多个模型,用ANSYS有限元程序进行线性和非线性分析,并进行比较分析,得出拱桥的拱轴线参数对几何非线性的影响,为此类桥型设计提供经验。 相似文献
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Shear behavior of partially encased composite I-girders with corrugated web has been investigated analytically and numerically in this paper. A 3-D finite element model with geometric and material nonlinearity is established and verified by the experiments. Subsequently, a parametric study is carried out to examine the effects of geometric and material properties on the shear behavior which includes corrugation, height, thickness, connection degree between steel web and concrete encasement. It is found that the ultimate shear strength of steel I-girders is improved with increases in the thickness, height and yield strength of corrugated web, while the ultimate shear strength of partially encased composite I-girders increases with the thickness, yield strength of corrugated web and the thickness, compressive strength of concrete encasement. However, the stud stiffness has little influence on the ultimate shear strength. Moreover, the concrete encasement improves the shear strength of steel I-girders, the degree of improvement increases with the thickness and compressive strength of the concrete, but decreases drastically with the thickness of corrugated web. Therefore, it is suggested that concrete should be poured on the corrugated web with thin thickness or low yield strength to prevent buckling occurrence before yielding of steel web. Finally, shear strength prediction equations are proposed and verified by numerical results. The calculated shear strength agree well with the numerical results for steel I-girders before and after composite with concrete, which indicates that the proposed analytical equations can be applied to predict the shear strength of such partially encased composite girders with corrugated web. 相似文献
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工程结构发生材料非线性时,往往伴随着几何大变形行为。而在非线性分析过程中,刚度矩阵的分解和求逆是不可避免的。该文将隔离非线性有限元法嵌入到更新拉格朗日格式中,建立了考虑材料非线性和几何大变形行为的梁单元控制方程。为了实现控制方程的高效求解,提出了近似Woodbury公式,其核心思想是:与舒尔补矩阵相关的线性方程组采用组合近似法求解,实时变化的整体刚度矩阵被假定在一段时间内保持不变,从而避免矩阵的实时更新和分解,拓宽了Woodbury公式的应用范围。依据时间复杂度分析,对该文方法进行了效率评估。结果表明:对于结构出现大范围材料非线性时的几何大变形问题,近似Woodbury公式依然具有高效性;通过对某钢筋混凝土框架结构进行地震反应分析,论证了该文方法在满足工程精度要求的前提下,能够高效求解结构出现大范围材料非线性时的几何大变形问题。 相似文献