Parametric analysis of steel bolted end plate connections using finite element modeling

This paper presents and discusses results of parametric analyses on the behavior of bolted extended end plate connections using Finite Element (FE) modeling tools. The analyses were calibrated to experimental results that are also briefly reviewed in this paper. The analytical models took into account material nonlinearities, geometrical discontinuities and large displacements. Comparisons between numerical and experimental data for moment-rotation curves, displacements of the end plate, and forces on bolts showed satisfactory agreement. Phenomenological T-stub failure models were also used for calculations of the flexural strength for the end plate. These models clearly support the numerical results and show how the interaction between the end plate and the bolts changes the connections’ behavior. The results presented herein show that failures associated with either formation of yield lines in the plate (Mode 1) or bolt tension failure (Mode 3) are well-defined, while failures due to combinations of these mechanisms (Mode 2) represent levels of interaction between the end plate and bolts that are difficult to predict accurately. These results also indicate that the T-stub analogy has limitations in representing the yield lines at the end plate, leading to limitations both in accounting for prying action and in predicting values for strength and stiffness of the connection.     

Refined 3D finite element modeling of partially-restrained connections including slip

This study presents an approach for refined parametric three-dimensional (3D) analysis of partially-restrained (PR) bolted steel beam-column connections. The models include the effects of slip by utilizing a general contact scheme. Non-linear 3D continuum elements are used for all parts of the connection and the contact conditions between all the components are explicitly recognized. A method for applying pretension in the bolts is introduced and verified. The effect of several geometrical and material parameters on the overall moment–rotation response of two connection configurations subject to static loading is studied. Models with parameters drawn from a previous experimental study of top and bottom seat angle connections are generated in order to compare the analyses with test results, with good prediction shown by the 3D refined models. The proposed 3D modeling approach is general and can be applied for accurate modeling of a wide range of other types of PR connections. A pronounced effect of slip and friction, between the connection components is shown with connections having thicker (stiffer) seat angles. This study demonstrates the effects of clamping through the bolts and contact between the components on the overall non-linear moment–rotation response. Equivalent moment–rotation responses of pull-test simulations are compared to FE model responses of full connections without web angles. The moment–rotation from the pull test is shown to be equivalent to that of the full FE model for small rotations. As the rotation increases a softer response is shown by the pull tests.     

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。     

Progressive collapse analysis of high-rise building with 3-D finite element modeling method

Using the general purpose finite element package ABAQUS, a 3-D finite element model representing 20 storey buildings were first built in this paper to perform the progressive collapse analysis. Shell elements and beam elements were used to simulate the whole building incorporating non-linear material characteristics and non-linear geometric behavior. The modeling techniques were described in detail. Numerical results are compared with the experimental data and good agreement is obtained. Using this model, the structural behavior of the building under the sudden loss of columns for different structural systems and different scenarios of column removal were assessed in detail. The models accurately displayed the overall behavior of the 20 storey buildings under the sudden loss of columns, which provided important information for the additional design guidance on progressive collapse.     

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.     

Simulation of tensile bolts in finite element modeling of semi-rigid beam-to-column connections

This paper presents an innovative bolt model suitable for the three dimensional finite element analysis (FEA) of the semirigid beam-to-column bolted connections. The model is particularly useful for the moment-rotation relationship of beam-tocolumn connections, especially in cases where the connectors such as endplates, angles, T-stubs, are not particularly thin. In this paper, the bolt tensile behavior is firstly discussed by using a refined finite element model, in which the complex geometries of both external and internal threads were modeled. Then, the bolt behavior predicted by the commonly used models was compared with that of the refined FEA to appraise the accuracy of these models. The comparison shows most of the models commonly used can not predict accurately the axial stiffness, carrying capacity and ductility of bolt simultaneously. Afterwards, an innovative bolt model was proposed and the model accorded with the refined FEA for single bolts. Finally, the proposed model was applied to analyze the moment-rotation behavior of several experimented and well documented connections with different configurations. The results indicate that the proposed model is feasible and efficient.     

Effects of connection geometry on block shear failure of welded lap plate connections

Although block shear failure has predominantly been considered a potential failure mode for bolted steel connections, several recent experimental programs have revealed that block shear can also govern the design of certain arrangements of welded connections. The mechanics of block shear failure in welded connections are known to be different from the bolted case, although published research on the subject is limited. A nonlinear finite element model has been developed to study the capacity of concentrically loaded welded lap plate connections that fail in block shear. The accuracy of the model was verified by comparing analytical results to those from physical tests. A parametric study was then completed to quantify the effects of connection geometry and weld arrangement. The results of the study are used to describe the behaviour of welded lap plate connections failing in block shear and to evaluate the performance of block shear design equations for capacity prediction of welded connections with a variety of geometries.     

高强度螺栓外伸端板连接有限元模拟方法研究

高强度螺栓外伸端板连接节点可用不同的有限元方法进行模拟.对典型高强度螺栓外伸端板连接的ANSYS有限元模拟方法进行了比较研究,分别建立了T型件简单模型和复杂实例进行有限元分析,通过对比有限元单元数量、建模难易程度以及计算耗时等,分析了各种有限元模拟方法的特点.通过有限元结果与试验结果的比较,给出了一种建议的模拟方法.研究结果表明,直接粘贴方法虽然具有建模简单的优点,但是该方法由于过分放大了连接板系统的强度和刚度,因而基于该方法获得的应力和位移都比实际情况小;耦合螺孔节点方法虽然能比较接近的模拟连接节点受力性能,但该方法的最大问题是耦合节点处的应力和位移会发生畸变,与实际情况不符;预拉力加接触方法虽然建模较复杂,但计算结果最为合理,与实际连接节点受力情况吻合较好.     

钢网格剪力墙力学性能试验研究及有限元分析

为解决现有加劲钢板剪力墙现场安装难度高、焊接工作量大等问题,提出了装配式钢网格剪力墙结构。为考察该抗侧力体系的静力性能和抗震性能,对2个缩尺模型进行了单调水平加载和低周往复加载试验。基于ABAQUS建立有限元分析模型,验证钢网格剪力墙有限元模型的准确性。研究结果表明：在单调荷载或低周往复荷载作用下,试验与有限元分析结果较为一致,试件均表现出良好的抗侧刚度、延性和耗能能力;其破坏过程为中间位置的T形钢构件首先出现全截面屈服,随着位移荷载的增大,靠近梁柱节点位置的较短T形钢构件开始局部屈服,最终所有T形钢构件均达到了全截面屈服,试件破坏形式为中部T形钢构件拉断,失效模式较为合理;试件破坏时的层间位移角均达到了3.6%以上,延性系数达到5.35以上,试件在每级荷载循环后的强度退化系数均在0.92以上,受力性能稳定。     

自攻螺钉抗剪连接破坏模式的有限元分析

介绍了螺钉连接受剪破坏的模式,通过对蒙皮自攻螺钉进行三维实体建模,总结了不同厚度钢板的破坏模式,给出了规律性的结论,以促进自攻螺钉抗剪连接破坏的研究.     

插筋灌浆连接水平拼缝受剪性能试验研究与有限元分析

对4个采用插筋灌浆连接的装配式混凝土剪力墙连接试件进行静力加载试验,采用已有的界面受剪承载力计算方法进行计算,并与试验结果进行对比。采用有限元分析软件Msc.Marc对插筋灌浆连接拼缝的受剪性能进行非线性有限元分析,在模型验证的基础上,分析了轴压比、插筋数量以及界面粗糙程度对拼缝受剪性能的影响。研究结果表明：试件的初始破坏为拼缝处混凝土与砂浆的界面破坏,拼缝处出现明显的剪切通缝;混凝土与砂浆界面黏结破坏以后,界面剪力主要由拼缝处的插筋承担,试件呈现良好的延性;达到极限荷载以后,随着试验墙体劈裂裂缝的不断增加以及裂缝处混凝土剥落,试件荷载下降。在实际工程设计中,为了尽量避免拼缝破坏发生在预制构件破坏之前,应按照要求增大拼缝插筋配筋率或选取较高强度等级的插筋。     

Finite element modeling of block shear failure in coped steel beams

Block shear is a potential failure mode that is encountered in the connection regions of coped steel beams. Limited experimental studies completed so far have shown that the block shear failure in coped steel beams is a complex phenomenon, which is highly dependent on the number of bolt lines. In this paper, the use of the finite element method in predicting the block shear failure load was studied by making comparisons with experimental findings. The effects of numerical modeling details on load capacity predictions were investigated. In light of these investigations, a finite element analysis methodology has been developed and used to conduct a parametric study. Simplified load capacity prediction equations were developed based on the results of the parametric study and are presented herein.     

Finite element modeling of bolted connections in thin-walled stainless steel plates under static shear

The recently performed experimental study indicates that the current Japanese steel design standards (AIJ) cannot be used to predict accurately the ultimate behavior of bolted connections loaded in static shear, which are fabricated from thin-walled (cold-formed) SUS304 austenite stainless steel plates and thus, modified formula for calculating the ultimate strength to account for the mechanical properties of stainless steel and thin-walled steel plates were proposed. In this study, based on the existing test data for calibration and parametric study, finite element (FE) model with three-dimensional solid elements using ABAQUS program is established to investigate the structural behavior of bolted shear connections with thin-walled stainless steel plate. Non-linear material and non-geometric analysis is carried out in order to predict the load–displacement curves of bolted connections. Curling, i.e., out of plane deformation of the ends of connection plates which occurred in test specimens was also observed in FE model without geometric imperfection, the effect of curling on the ultimate strength was examined quantitatively and the failure criteria which is suitable to predict failure modes of bolted connections was proposed. In addition, results of the FE analysis are compared with previous experimental results, failure modes and ultimate strengths predicted by recommended procedures of FE showed a good correlation with those of experimental results and numerical approach was found to provide estimates with reasonable accuracy.     

Finite element modelling of single lap screw connections in steel sheeting under static shear

The behaviour of sheeting connections is important in thin walled structures, especially when diaphragm skin action is considered for these structures. Thousands of tests have been carried out in many countries but the study results are still not satisfactory. We felt that it would be very helpful to do more studies on this subject not only by experimental analysis but numerically, as well. Therefore, a finite element model is proposed, in this study, to simulate single lap screw connections in steel sheeting of different thicknesses, under static shear. This model can be used to predict the ultimate resistance, deformation, screw rotation and stress distribution of the connections. The results show a good correlation with the test results. This model can therefore be used in further relevant parametric studies and with little change adapted to model the connections with other types of fasteners.     

高强螺栓外伸端板撬力作用的有限元分析与设计方法

针对外伸端板与T型连接设计中考虑撬力影响的问题,利用ANSYS进行了三维非线性有限元分析,考虑了材料非线性、几何非线性、高强螺栓的预拉力、端板间接触压力的影响。证明了撬力的存在以及螺栓拉力的分布是以受压翼缘位置为转动中心的梯形分布,提出了外伸端板连接中螺栓拉力的计算模型。研究了高强螺栓受拉连接采用外伸端板或T型接头的破坏机理以及撬力作用计算理论。介绍了国内外关于外伸端板与T型连接设计中考虑撬力作用的端板厚度设计方法,为工程设计提供了参考依据。     

Finite element investigation of shear failure of lean duplex stainless steel plate girders

The use of duplex stainless steel material has gained popularity in the last two decades thanks to its nature that combines well the advantages of both austenitics and carbon steel materials. The duplex grades offer a combination of higher strength than austenitics in addition to a great majority of carbon steels with similar or superior corrosion resistance. However, high nickel prices have more recently led to a demand for lean duplexes with low nickel content, such as grade EN 1.4162. Wide-ranging work is needed to include the lean duplex grade EN 1.4162, into design standards such as EN 1993-1-4. Accordingly, a finite element modelling for full-size lean duplex stainless steel plate girders of non-rigid end stiffeners of Grade EN 1.4162 is presented in this paper. The paper is principally concerned with shear failure mechanism characteristics of this type of plate girders, which is not yet investigated. The ABAQUS 6.6 programme, as a finite element package, is used in the current work. The lean duplex stainless steel material is simulated here based on an accepted stainless steel material model available in the literature. A number of transversely stiffened I-section plate girders having equal depth of 1000 mm in span of 4 m is considered and parametric studies regarding flange width-to-web depth ratio, flange-to-web thickness ratio and web plate slenderness are carried out. However, new conclusions on shear strength of lean duplex stainless steel plate girders are presented.     

复合路面荷载应力三维有限元分析结果

针对上连溪隧道的复合路面结构，运用通用有限元程序ANSYS模拟复合路面的结构建立复合路面的结构模型，对复合路面在标准轴载作用下的位移、应力的大小及其变化规律进行了研究，验证了上连溪隧道设计的合理性。     

带竖缝钢板剪力墙滞回性能有限元分析

阐述了带竖缝钢板剪力墙是一种新型的抗侧力构件,具有良好的结构性能,通过ANSYS对其进行有限元模拟分析,分析了其滞回性能,并与试验结果进行比较,分析其产生误差的原因,指出设计时应注意的问题。     

兰州某深基坑三维有限元分析

对兰州某实际工程通过方案优选,提出上部采用土钉墙、下部采用排桩预应力锚杆联合支护技术,并进行了支护结构及降水设计。采用大型非线性分析软件对其进行了开挖支护与降水施工全过程模拟,得到了基坑周围地下水渗流场和位移场分布,支护结构内力变化情况。将有限元计算值与实际监测进行了对比,二者比较接近。结果表明该联合支护体系是一种有效的支护技术,可为兰州地区类似工程的支护及降水设计提供有益参考。     

Finite element modelling of steel fin plate connections in fire

Recent structural collapses caused by fire have focused attention on research concerning fire safety in building design. Steel connections are an important component of any structural steel building, as they provide links between the principal structural members. The evaluation of the performance of steel connections at elevated temperatures has been a topic of several research programmes in the last few years. Determining the behaviour, available strength and stiffness of moment connections in fire conditions has been a dominant theme in these research works; however very little information on the behaviour of simple shear connections in fire conditions has been disseminated. Fin plate shear connections are easy to fabricate and install; as a result, they have gained popularity with fabricators because of their economy. In this research, the robustness of simple fin plate beam-to-column connections is being investigated under catenary tension from highly deflected beams in fire. A highly detailed three-dimensional (3-D) finite element (FE) model has been created using the ABAQUS software. This is a complex model accounting for material and geometric non-linearity, large deformation and contact behaviour. Contact is critical to model the shear behaviour of the joint, and contact elements have been used both at the bolt–hole interface and also at the surface between the web of the beam and the fin plate, taking into consideration friction between the surfaces. The connection model has been analysed through the elastic and plastic ranges up to failure. Bolt shear and bending, and plate and web bearing have been observed as failure modes. A comparison between available experimental data at ambient and elevated temperatures and other analytical results shows that the model has a high level of accuracy. When the connection model was extended to include an attached beam, it was found that it eventually experiences large tensile force when exposed to fire.