不锈钢焊接截面薄腹梁剪切屈曲计算方法

建立精细的有限元模型对不锈钢焊接截面薄腹梁剪切屈曲性能进行数值模拟,并依据试验结果对模型进行验证。基于验证可靠的有限元模型,对构件局部几何初始缺陷、刚性封头肋板、不锈钢材料力学性能等关键参数开展系统分析。结合所得的数值计算结果和现有的试验数据,对我国GB 50017—2017《钢结构设计标准》和EN 1993-1-4+A1《欧洲不锈钢结构设计规范》中的抗剪承载力计算方法进行评估,在此基础上提出了可同时考虑腹板与翼缘的抗剪承载力以及刚性封头肋板等因素影响的承载力计算式。与试验和有限元计算结果比较表明:所建议的计算方法可以更加准确计算不锈钢焊接截面薄腹梁的剪切屈曲承载力。     

工字梁的抗剪极限承载力

对工字梁腹板抗剪极限承载力的研究进行总结,对各种公式与文献中的试验结果进行对比,将拉力场理论和转向应力场理论的假定与ANSYS分析揭示的腹板应力发展变化规律进行对比,指出了假定和数值分析结果的不一致。提出了翼缘对腹板转动约束的合理参数,得到精度良好的考虑翼缘约束的腹板剪切屈曲系数。利用得到的屈曲系数,考虑翼缘抗弯承载力的贡献,提出新的工字梁抗剪极限承载力的计算公式。与现有试验数据和ANSYS非线性有限元分析结果的对比,证实建议方法离散性较小,适用范围广,尤其是对于通用高厚比较大的梁,较以往方法有了较大改进。     

基于修正软化拉-压杆模型的型钢#br# 混凝土深梁受剪承载力研究

为研究型钢混凝土深梁的受剪承载力,完成7组型钢混凝土深梁的静力试验和有限元分析,主要考虑剪跨比、型钢腹板高度及翼缘宽度等影响因素。试件的破坏模式为斜压破坏和剪切破坏。剪跨比对破坏形态有较大影响,较大的型钢腹板高度和翼缘宽度显著提高试件受剪承载力。在试验研究和有限元分析的基础上,考虑钢筋混凝土部分的软化效应、非软化混凝土与型钢翼缘的协调变形作用及腹板部分的受剪贡献,建立修正软化拉-压杆模型,并采用叠加原理推导型钢混凝土深梁受剪承载力实用计算方法。结果表明：修正软化拉-压杆模型能较好地反映型钢混凝土深梁的破坏特征和受力机制,文中提出的受剪承载力计算方法与试验数据吻合较好,对受剪影响因素考虑更加全面,能较好地预测型钢混凝土深梁的受剪承载力。     

铝合金工字形截面的抗剪承载力研究

提出了考虑腹板屈曲后强度和翼缘约束效应的铝合金工字形截面的抗剪设计方法,并给出实用的建议设计公式。采用有限元方法模拟铝合金工字形截面的受力变形,并对已有工字形截面的抗剪承载力计算理论进行分析。有限元方法得出的荷载-位移曲线反映出铝合金工字形截面腹板弹性剪切屈曲力相当低,而构件整体抗剪承载力却相对较高,传统钢构件的设计方法不能准确反映其实际抗剪能力。在此基础上指出对于铝合金材料制成的工字形截面,抗剪设计公式应准确、方便的计算腹板受剪屈曲后承载力和翼缘对截面抗剪承载力的贡献。经数据比对,建议设计公式的计算结果和Hamoodi M J、Burt C A和Evans H R的试验资料及现行的欧洲铝合金规范公式计算结果吻合,且公式计算简捷。     

钢-竹组合箱形截面梁受剪性能试验研究

为研究以冷弯薄壁型钢和竹材人造板通过结构胶复合而成的箱形截面钢-竹组合梁的受剪性能,以梁截面的翼缘及腹板竹胶板厚度、型钢翼缘宽度和剪跨比等为主要参数,对6根钢-竹组合箱形梁进行受剪试验,观察各级荷载作用下组合梁的应变和挠度发展,分析其破坏过程和破坏机理,研究组合梁受剪性能的影响因素,探讨钢-竹组合箱形梁的受剪承载力及变形计算方法。研究结果表明:钢-竹组合箱形梁整体工作性能优良且组合效应显著,其受力过程经历弹性和弹塑性两个阶段,具有良好的延性和安全储备;增加翼缘和腹板处竹胶板厚度可提高组合梁的受剪承载力,减小剪跨比可有效提高组合梁的受剪能力,同时适当减小型钢翼缘宽度能使梁的受剪性能进一步增强;采用所提出的组合梁的跨中挠度计算公式得到的计算值与试验值吻合较好,组合梁受剪承载力的计算公式所得结果偏于保守。     

Experimental study on shear behavior of box section bamboo-steel composite beams

为研究以冷弯薄壁型钢和竹材人造板通过结构胶复合而成的箱形截面钢-竹组合梁的受剪性能,以梁截面的翼缘及腹板竹胶板厚度、型钢翼缘宽度和剪跨比等为主要参数,对6根钢-竹组合箱形梁进行受剪试验,观察各级荷载作用下组合梁的应变和挠度发展,分析其破坏过程和破坏机理,研究组合梁受剪性能的影响因素,探讨钢-竹组合箱形梁的受剪承载力及变形计算方法。研究结果表明：钢-竹组合箱形梁整体工作性能优良且组合效应显著,其受力过程经历弹性和弹塑性两个阶段,具有良好的延性和安全储备;增加翼缘和腹板处竹胶板厚度可提高组合梁的受剪承载力,减小剪跨比可有效提高组合梁的受剪能力,同时适当减小型钢翼缘宽度能使梁的受剪性能进一步增强;采用所提出的组合梁的跨中挠度计算公式得到的计算值与试验值吻合较好,组合梁受剪承载力的计算公式所得结果偏于保守。     

不锈钢工字型梁抗剪承载力的参数分析

为了解不锈钢工字型梁的极限抗剪承载力,利用通用软件ABAQUS对不锈钢工字型梁进行了有限元分析,考虑的参数有腹板宽度、腹板厚度、翼缘宽度和厚度等。分析结果表明:不锈钢工字型梁的破坏机理同普通碳素钢梁,均在腹板内形成拉力场,翼缘仅对腹板屈曲后的承载能力产生明显的影响;若腹板宽度过大,考虑到极限承载后的不稳定性以及低延性等因素,建议不锈钢工字型梁腹板的宽度不易大于腹板高度的2倍。     

局部锈蚀影响下钢箱梁腹板剪切屈曲分析

为分析局部锈蚀钢箱梁腹板在纯剪荷载作用下的屈曲特性,对不同翼缘宽度、厚度、腹板宽高比和锈蚀体积损失(DOPV)影响下的腹板剪切屈曲强度进行了有限元计算,并基于工字钢梁腹板屈曲强度计算式,得到了钢箱梁腹板剪切屈曲系数计算式;提出了能衡量钢箱梁锈蚀腹板剩余强度的系数η,拟合了局部锈蚀钢箱梁腹板剪切屈曲强度的计算式。     

弯剪共同作用下不锈钢薄腹梁承载性能试验研究

为研究不锈钢薄腹梁在弯矩和剪力共同作用下的承载性能,进行了6根焊接工字形截面不锈钢梁的试验研究.结果 表明,所有梁试件的破坏形态为结合了腹板剪切屈曲和受压区板件局部鼓曲的弯剪联合屈曲.建立精细有限元数值模型对试验过程进行模拟,同时考虑了不锈钢材料、几何双非线性,局部几何初始缺陷和焊接残余应力的影响.基于得出的试验和有限...     

冷弯薄壁型钢受弯构件局部屈曲性能研究

采用有限条程序CUFSM对截面形式为TS40和TS61的19根550MPa高强冷弯薄壁型钢帽形截面简支檩条受弯构件局部屈曲应力进行分析,计算结果与试验值吻合较好。利用有限条程序对帽形截面受弯构件的翼缘宽厚比、腹板翼缘宽度比、卷边翼缘宽度比、腹板翼缘夹角等参数进行计算分析,结果表明腹板翼缘宽度比是影响帽形截面简支檩条受压翼缘局部屈曲稳定系数的重要因素。利用考虑板组相关的我国现行规范GB50018-2002《冷弯薄壁型钢结构技术规范》和英国冷成型薄壁构件设计标准(BS5950-5:1998)对帽形截面简支檩条受压翼缘局部屈曲稳定系数进行计算分析表明:我国规范在腹板翼缘宽度比小于1.5时偏于不安全,大于1.5时偏于保守,而英国规范相对比较安全。在参数分析的基础上,提出了考虑板组相关的帽形截面简支檩条受压翼缘弹性局部屈曲稳定系数计算公式,建议公式可供工程设计和修订规范参考。     

Shear resistance in stainless steel plate girders with transverse and longitudinal stiffening

This paper summarizes and presents main results of the investigation conducted in the Department of Construction Engineering of the UPC dealing with shear behaviour of stainless steel plate girders. Initial shear buckling stress together with ultimate shear capacity of these structural elements have been evaluated with special attention paid to the effect of including stiffeners, both transverse and longitudinal. The studies conducted, both numerical and experimental tests, have permitted the development of new and simple design expressions to determine more accurately the initial shear buckling stress in stainless steel web panels and the ultimate capacity of plate girders considering the presence of a rigid or non-rigid end post.     

Shear buckling characteristics of cold-formed steel channel beams

Cold-formed steel members are increasingly used as primary structural elements in the building industries around the world due to the availability of thin and high strength steels and advanced cold-forming technologies. Cold-formed lipped channel beams (LCB) are commonly used as flexural members such as floor joists and bearers. However, their shear capacities are determined based on conservative design rules. For the shear design of LCB web panels, their elastic shear buckling strength must be determined accurately including the potential post-buckling strength. Currently the elastic shear buckling coefficients of LCB web panels are determined by assuming conservatively that the web panels are simply supported at the junction between their flange and web elements. Hence finite element analyses were conducted to investigate the elastic shear buckling behavior of LCBs. An improved equation for the higher elastic shear buckling coefficient of LCBs was proposed based on finite element analysis results and included in the ultimate shear capacity equations of the North American cold-formed steel codes. Finite element analyses show that relatively short span LCBs without flange restraints are subjected to a new combined shear and flange distortion action due to the unbalanced shear flow. They also show that significant post-buckling strength is available for LCBs subjected to shear. New equations were also proposed in which post-buckling strength of LCBs was included.     

钢板结构中计算剪切屈曲应力的实用公式

对不锈钢板结构剪切屈曲的抵抗能力进行深入分析,并进行总结。推导了计算钢板剪切屈曲临界应力的计算公式,公式中通过两个剪切屈曲系数η和Kres,考虑了材料非线性和板的实际边界条件。η主要用于量化材料非线性,Kres则主要考虑板实际边界条件的影响。     

剪切作用下锥形板梁的试验和数值研究

对剪切作用下的锥形钢板梁进行了试验和数值研究。试验包含4个缩尺锥形钢板梁试件,主要研究其临界剪切荷载和极限抗剪强度。此外,研究了锥形板的后屈曲特性。另外,对不同几何形状的锥形板进行了参数研究,以找到最有利的设计方案。分析的参数有:板的高宽比、翼缘的倾斜角、腹板和翼缘的长细比。由于性能的不同,对4种类型的锥形板梁分别进行建模和数值模拟。欧洲规范EN1993-1-5给出的锥形板的简化方法证实,在某些情况下,估计的极限剪切强度偏于不安全,需要进行修改。     

Experimental behaviour of a thermally restrained plate girder loaded in shear at elevated temperature

This paper outlines an experimental investigation of twelve simply supported steel plate girders subjected to shear loading at elevated temperature. Three different series of steel plate girders have been tested at three constant elevated temperature levels. Additional axial restraints were applied onto beams to simulate the thermal restraint effects of adjacent cooler parts of steel-framed structure in fire. Based on test results and observations, the pre- and post-buckling behaviours of plate girder web panels at high temperature were discussed. In addition, finite element modelling of the web panels was conducted and numerical models generally agreed well with test results. It was observed that the ultimate shear capacity decreased significantly under a thermal restraint effect.     

Elastic shear buckling characteristics of LiteSteel beams

LiteSteel beam (LSB) is a new cold-formed steel hollow flange channel beam. The unique LSB section is produced by a patented manufacturing process involving simultaneous cold-forming and dual electric resistance welding. To date, limited research has been undertaken on the shear buckling behaviour of LSBs with torsionally rigid, rectangular hollow flanges. For the shear design of LSB web panels, their elastic shear buckling strength must be determined accurately including the potential post-buckling strength. Currently the elastic shear buckling coefficients of web panels are determined by assuming conservatively that the web panels are simply supported at the junction between the flange and web elements. Therefore finite element analyses were carried out to investigate the elastic shear buckling behaviour of LSB sections including the effect of true support conditions at the junction between their flange and web elements. An improved equation for the higher elastic shear buckling coefficient of LSBs was developed and included in the shear capacity equations of Australian cold-formed steel codes. Predicted ultimate shear capacity results were compared with available experimental results, both of which showed considerable improvement to the shear capacities of LSBs. A study on the shear flow distribution of LSBs was also undertaken prior to the elastic buckling analysis study. This paper presents the details of this investigation and the results including the shear flow distribution of LSBs.     

Ultimate flexural strengths of plate girders subjected to web local buckling

The ultimate flexural strengths of bisymmetric and monosymmetric I-girders subjected to local bend-buckling in webs have been investigated by nonlinear finite element analysis incorporating post-buckling behaviors. The plate girders fabricated with high performance steel (HPS) and conventional steel were modeled three-dimensionally with thin shell elements and ultimate strength analyses were conducted utilizing versatile nonlinear techniques provided by a commercial finite element analysis (FEA) package program, ABAQUS. The constitutive relationship for both HPS and conventional steel was assumed to be elasto-plastic strain-hardening, and the initial imperfections were considered in the web panels and the residual stresses were imposed on the hypothetical built-up sections. The ultimate flexural strengths of girders with various slenderness of web were evaluated from the nonlinear FEA and compared with values predicted by the specifications in AASHTO LRFD and Eurocode 3. It has been found that the current flexural strength formulas for conventional steel girders from AASHTO LRFD and Eurocode 3 can be extended to application for HPS girders without modification.     

General behaviour and effect of rigid and non-rigid end post in stainless steel plate girders loaded in shear. Part II: Extended numerical study and design proposal

After the deep analysis and evaluation of the experimental and numerical results obtained during the described experimental campaign [Estrada I, Real E, Mirambell E. General behaviour and effect of rigid and non-rigid end post in stainless steel plate girders loaded in shear. Part I: Experimental study. Journal of Constructional Steel Research 2005 [submitted for publication]], an extended numerical analysis in code ABAQUS [Hibbit, Karlsson and Sorensen Inc., ABAQUS/Standard, Version 6.3. User’s manual. Rhode Island (USA); 2002] has been carried out dealing with the evaluation of the postbuckling strength in stainless steel plate girders. Finally, a proposal of design expressions for predicting their ultimate shear capacity is made since current design specifications dealing with shear resistance included in Eurocode 3, Part 1-4 [European Committee for Standardisation. ENV 1993-1-4. Eurocode 3: Design of steel structures. Part 1.4: General rules—supplementary rules for stainless steel. Brussels; 1996] have been demonstrated to be overly conservative.Taking special attention of the material non-linearity and the rigid or non-rigid condition of the end post, specimens covering a wide range of slenderness and aspect ratios (a/d from 0.5 to 3.0) have been numerically tested. Austenitic and Duplex stainless steel grades, which are the most commonly used in construction, have been evaluated during the whole analysis development.Finally, a new design proposal based on the Rotated Stress Field model developed by Höglund [Höglund T. Shear buckling resistance of steel and aluminium plate girders. Thin-Walled Structures 1998;29(1-4):13-30], adequately adapted to the particular features of stainless steel is presented in order to reach a more optimum use of this relatively modern resistant material in construction.     

Investigation on the Collapse Behavior of Diagonal Stiffened Composite Plate Girders Subjected to Shear Loading

In this study, a new analytical method is presented to estimate the shear capacity of diagonally stiffened steel–concrete composite plate girders. This method is formulated based on tension field action in steel girder web and failure mechanism of concrete slab deck. To validate the accuracy of the proposed method, the obtained results are compared with three-dimensional finite element analysis of composite plate girders with different configuration of stiffeners. The results of analytical and numerical investigations indicate that the proposed method can accurately estimate the ultimate shear capacity of composite plate girders. In addition, it is shown that the diagonal stiffeners on one hand can reduce the buckling effects of shear panel of girders and on the other hand can increase the strength of elastic shear buckling and ultimate shear capacity of girders well in comparison with the unstiffened thin steel plate girders.