半刚性端板连接节点性能的非线性有限元分析

采用三维接触单元来模拟端板与柱翼缘的接触面,预应力单元来模拟螺栓的预拉力,对半刚性端板连接节点性能进行了非线性有限元分析。计算结果的比较分析表明,节点域加劲肋、端板加劲肋、端板厚度、螺栓预拉力、应力集中等因素对半刚性端板连接节点域的受力性能均有较大影响。建议在设计中采取相应构造措施,考虑端板节点半刚性的不利影响。     

外伸端板连接钢框架抗震性能试验研究

通过对外伸端板半刚性高强螺栓连接钢框架在低周往复荷载作用下的试验,研究该类型结构的破坏形态、变形性能、骨架曲线、延性等,分析了外伸端板半刚性高强螺栓连接钢框架的受力特点及抗震性能。     

外伸式端板螺栓连接节点的有限元分析

利用有限元ANSYS对外伸式端板螺栓连接节点受力性能进行了分析,从改变端板厚度和螺栓直径方面进行了节点受力性能研究,提出了钢框架结构设计节点时可按构造形式划分螺栓受力模型。     

外伸端板半刚性连接的初始刚度研究

钢结构中的梁柱节点并不是完全刚接或者完全铰接,而是属于半刚性连接.针对外伸端板半刚性连接,利用组件法推导其初始刚度的预测计算公式,并利用已有的试验数据验证其正确性,为实际工程中的应用奠定了理论基础.     

外伸端板连接节点撬力分布研究

撬力是外伸端板连接节点存在的不可忽略的影响因素,其大小和分布与连接节点外伸端板和螺栓的刚度、螺栓布置等因素有关,很难准确地量测。通过变化端距、栓距和端板厚度等建立了一系列有限元模型,对外伸端板连接节点撬力分布进行了分析研究。根据计算结果拟合了撬力分布模型,并提出撬力合力作用位置计算公式。分析了端板构造变化对撬力的影响,给出了端板构造设计建议。结果表明,撬力是分布在端板外伸部分的不均匀的面荷载,提出的撬力分布模型与有限元结果吻合良好。给出的撬力合力作用位置计算公式可反映不同构造形式对撬力作用位置的影响,使得设计更加精确。给出的端板构造设计建议可有效地减小撬力影响。研究结果可为工程设计提供参考。     

外伸端板半刚性节点在循环荷载作用下的研究

介绍了钢框架梁柱采用梁端外伸端板与柱翼缘之间高强螺栓连接的半刚性节点在循环往复荷载作用下的试验过程和结果 .分析了四种不同形式节点的承载能力和延性特征 .依据试验结果 ,对半刚性节点提出了增加节点延性、防止脆性破坏的构造措施 ,为钢框架梁柱半刚性节点的设计提供了试验依据 .     

加腋型外伸端板高强螺栓节点设计

工业钢结构高强螺栓梁柱节点设计中,需要多种施工方便、抗震性能优良且具有较高承载力的梁柱连接节点,目前可选择的类型很少。根据美国SAC报告中四螺栓天肋(4E节点)的试验数据,用ANSYS软件模拟外伸端板梁柱节点试验加载的全过程,在此基础上给出加腋型外伸端板梁柱节点的设计方法。工程实践表明:该加腋型节点满足石化工业的需要并有良好的经济效益,值得推广应用。     

外伸端板SMA螺栓连接自复位钢框架去柱抗倒塌性能分析

为明晰外伸端板形状记忆金属(Shape memory alloy,简称SMA)螺栓梁柱连接自复位钢框架去柱后结构的抗倒塌性能,采用ANSYS软件建立了梁、实体混合单元模型。在验证有限元模型合理的基础上,进行外伸端板SMA螺栓、高强度螺栓柱连接去柱子结构竖向加载分析,并对比两类试件的受力性能及复位效果。研究表明:两类试件应力(应变)分布相似,且应力集中在外伸端板上侧及梁翼缘与端板连接处;中柱竖向力-位移曲线呈三段式分布,SMA螺栓连接试件加载后期悬链作用显著,且竖向承载力高于高强度螺栓连接试件; SMA螺栓连接可有效减小结构残余变形,降低结构的修复难度,提高修复的经济性。     

门式刚架轻钢结构端板连接节点承载性能的有限元分析

采用ANSYS有限元软件建立了考虑接触和螺栓预拉力的三维有限元模型,对带加劲肋的外伸式端板连接节点进行了非线性分析,讨论了端板厚度、连接形式对端板连接节点的承载力和节点刚度特性的影响,同时对现行规范的相关设计原则进行了分析和验证,并提出了一些设计建议。     

翼缘削弱型外伸式端板连接节点在梁柱弱轴方向的受力性能研究

通过ANSYS有限元程序,对翼缘削弱型端板连接节点进行了单调加载和低周反复荷载作用下非线性有限元分析,研究翼缘削弱型端板连接节点的破坏形式和受力性能。分析结果表明:在梁柱弱轴方向,翼缘削弱型端板连接具有较大的连接刚度和理想的滞回性能;梁翼缘处的焊缝强度是决定翼缘削弱型端板连接节点性能的主要因素,这为翼缘削弱型节点的研究和应用提供了理论依据。     

FE model of beam-to-column extended end-plate joints

The rotational behaviour of steel end-plate connections can be studied using the finite element method for the following three reasons: 1) such models are inexpensive and robust; 2) they allow the understanding of local effects which are difficult to measure accurately physically; and 3) they can be used to generate extensive parametric studies. This paper presents a full three-dimensional ANSYS finite element model of steel beam to column bolted extended end-plate joints for use to obtain their behaviour. The model includes: contact and sliding between different elements; bolt pre-tension; and geometric and material non-linearity.The model was calibrated and validated with experimental results found in the literature and with the model proposed by Eurocode 3. The results from the finite element analysis were verified by comparing the obtained moment-rotation curve of the joint. The procedure for determining the moment-rotation curve using finite element analysis is also given, together with a brief explanation of how the design moment resistance and the initial rotational stiffness of the joint are obtained.     

Experimental study and spring-component modelling of extended end-plate joints in fire

In order to investigate the fire-resistant capacity of extended end-plate joints, an experimental study was performed by using a furnace on four full-scale specimens made with H-shaped steel. The failure characteristics and failure modes of the extended end-plate joint specimens in fire were obtained from the experiment. The influence of rib stiffeners and depth of end-plates on fire-resistant capacity of the joints was found by comparing the capacity of the joints with and without rib stiffeners and different depths of end-plate. In addition, this paper also describes a spring-component model employed for predicting the behaviour of extended endplate bare-steel joints at elevated temperature. The components of a joint are considered to consist of spring components with predefined mechanical properties, i.e. stiffness and strength. The response of the joints subjected to elevated temperature can be predicted by assembling components, the stiffness and strength of which are assumed to degrade with increasing temperatures based on the recommendations presented in the Chinese Technical Code on Fire Safety of Steel Building Structure. It is demonstrated that the results from the model agree with experimental data quite well.     

A practical approach for fire resistance design of extended end-plate joints

Although beam-to-column joints are known to have a very significant effect on the behaviour of steel frames in the event of fire, no specific approach for evaluating the behaviour of extended end-plate joints in fire has been proposed. In this paper, on the basis of the current Chinese Code for Design of Steel Structures [Chinese code for design of steel structures. 2002] and Technical Code on Fire Safety of Steel Building Structures [Chinese Technical code on fire safety of steel building structure. CECS, 2006], analysis is presented on the load-bearing capacity of extended end-plate joints in fire, by taking the mechanical properties of steel at elevated temperature into account. A practical approach for fire-resistance calculation and assessment of the joints is proposed, based on the load-bearing capacity of the components of joints at elevated temperatures including the bolt, extended end-plate, column flange and panel zone. Employing the practical approach, the critical temperatures of two extended end-plate joints are predicted. By comparison with the results measured from the tests, the effectiveness of this practical approach is verified.     

Energy dissipation capacity of an unstiffened extended end-plate connection with a SMA plate

International Journal of Steel Structures - The unstiffened extended end-plate connection exhibits different behavioral characteristics and energy dissipation capacities depending on the thickness...     

高强钢端板连接节点火灾下和火灾后初始刚度计算方法研究

为精准预测高强钢端板连接节点在常温、高温及过火冷却后的力学性能,基于组件法推导了高强钢端板连接节点初始刚度计算方法.为验证该方法的准确性,对比了采用该计算方法和现有计算方法计算得到的高强钢端板连接节点常温、高温及过火冷却后初始刚度的计算值和试验值.研究结果表明,大部分节点初始刚度的试验结果高于计算结果,但相较于欧洲规范EN 1993-1-8推荐方法的计算结果,本文提出的初始刚度计算方法可更准确地反映高强钢端板连接节点在常温、高温及过火冷却后的力学性能.     

端板厚度对梁柱外伸端板节点滞回性能的影响

对钢框架梁柱外伸端板连接节点的端板采用三种不同厚度进行有限元分析,得到其滞回性能曲线,分析了端板厚度对节点抗震性能的影响规律,指出端板厚度不宜过薄,边薄将降低承载力,但也不宜过厚,过厚将使延性变差。     

Research on end-plate connection with non-completely penetrated welds

A series of tests were executed for H-shaped beams whose flanges were connected to end-plate by non-completely penetrated welds. The welds were designed by equal capacity rule and the beams were mainly composed of non-compact or slender elements. The parameters introduced are width-thickness ratios of beam flange and web, end-plate thickness, angle between flange plane and end-plate plane and so on. 24 pieces of specimens were tested to failure under monotonic loading and 6 under cyclic loading. For comparison, a few of the specimens are those with completely penetrated groove welds. Finite element (FE) analysis was also carried out to study the effect of parameter change on the resistance of the welds. The parameters involved end-plate thickness, weld size, column flange thickness and bolt gauge. The results show that thinner end-plate and greater bolt gauge will deteriorate the resistance of weld. As long as the components are properly designed, as done in tests, the connections will not fail at the welds no matter what kind of weld form is adopted. In addition, weld form has no obvious effect on the ultimate loads and cyclic behavior of specimens. It is confirmed that the non-completely penetrated welds connecting flanges of H-shaped beams and end-plates can be used both under static loading and seismic loading in low-rise building structure where local buckling of the member is the predominant factor.     

外伸端板加劲肋试验和有限元研究

为研究梁柱外伸端板螺栓连接中端板加劲肋对节点刚度和承载力的影响,对外伸端板加劲肋进行系统分析.给出三角形加劲肋较无限长矩形加劲板受拉强度效率系数的计算公式,并基于端板外伸加劲肋的传力及翼缘内外侧螺栓拉力均衡的考虑提出加劲肋形状和厚度的设计方法.对6个无加劲和3个加劲T形件连接节点进行试验研究,并对多个外伸端板连接节点模型进行有限元分析.研究结果表明,工程中常用加劲肋会过早屈服,起不到理想的加劲效果;推荐方法设计的端板加劲肋能够很好地满足<门式刚架轻型房屋钢结构技术规程>(CECS102:2002)所隐含的加劲肋使端板外伸部分由一边固支三边自由板变为两相邻边固支板的要求.     

混合连接的装配式框架节点抗震性能试验研究

提出两种新型的装配式高强钢筋混凝土节点连接形式,通过对装配式高强钢筋混凝土框架中节点的拟静力试验研究,对比分析装配式高强钢筋混凝土框架梁柱中节点的开裂破坏形态、滞回曲线、骨架曲线、刚度退化、耗能能力等抗震性能指标.研究结果表明:装配式高强钢筋混凝土节点具有较好的抗震能力.装配式高强钢筋混凝土框架节点的极限荷载和耗能能力...     

Random material variability effects on full-strength end-plate beam-to-column joints

In the seismic design of steel frames, beam-to-column joints are generally designed as full strength joints in order to avoid their engagement in the plastic range promoting the location of plastic hinges at the ends of the connected beams. In this paper, the reliability of the criteria to design full strength beam-to-column joints is investigated. In particular, in the first part of the work, starting from probabilistic analyses accounting for random material variability of connecting elements, the reliability of the design criteria suggested by codes is analyzed. Successively, on the basis of the obtained results, a new design criterion able to account for both the random material variability and the overstrength exhibited by the beam before the occurrence of local buckling is proposed.