残余应力对Q550高强度焊接H型钢柱承载力影响分析

借助有限元软件,以轴心受压H型钢柱为研究对象,对其极限承载力进行分析研究,探讨残余应力对其极限承载力的影响。分析结果表明:翼缘端部的残余应力峰值对H型钢柱影响最大,翼缘中点的峰值影响次之,腹板中点的峰值影响最小,现有钢结构设计规范应用于Q550高强钢轴心受压构件极限承载力的计算略微保守。     

初弯曲和残余应力对箱型钢柱稳定极限承载力的影响

采用有限元方法分析了初弯曲和残余应力对常用长细比范围内箱型钢柱稳定极限承载力的影响,同时考虑了几何非线性和材料非线性,并通过荷载-位移曲线确定箱型钢柱受压稳定极限承载力.通过分析得出,初弯曲对箱型钢柱轴心受压稳定极限承载力影响较大,残余应力的影响相对较小,当既有初弯曲又有残余应力时,柱的稳定极限承载力将大为下降.这可以为今后实际工程中箱型钢柱的设计和计算提供一定的参考.     

残余应力峰值对H型钢柱极限承载力的影响研究

以有限元分析软件ANSYS为工作平台,基于非线性板壳有限元分析理论,采用大挠度弹塑性分析方法,考虑初始缺陷的影响,计算有不同热轧残余应力峰值下的H型钢柱的极限承载力,得到主要影响钢柱极限承载力的因素,为热轧残余应力的统计提供一些参考意见。     

高强Q690钢柱高温下轴心受压局部稳定设计方法（英文）

局部屈曲是钢结构构件的一种破坏模式,钢结构发生局部屈曲破坏时,屈曲应力小于钢材的屈服强度。为了研究高温下高强Q690钢柱的局部稳定性能,采用有限元软件ABAQUS建立有限元模型,模型采用其他学者完成的Q460钢柱轴心受压局部屈曲试验进行验证,考虑宽厚比、温度、初始缺陷、残余应力和翼缘与腹板之间相互作用的影响,对高强Q690钢柱进行参数分析。研究结果表明:宽厚比对局部屈曲有显著影响,宽厚比的增大导致试件极限承载力的降低;初始缺陷和残余应力对局部屈曲应力有较大影响,且试件的极限承载力随着温度的升高而明显下降。基于有限元分析结果提出了适用于高强Q690钢柱高温下的局部稳定设计方法和宽厚比限值,并与GB50017-2017、Eurocode 3和ANSI/AISC 360-10中的设计方法进行了比较。     

局部屈曲变形损伤对H型钢柱竖向剩余承载力影响的试验研究

以1.5m高HW100×100×6×8热轧H型钢柱为研究对象,分别对6个因侧向撞击而受损的H型钢柱试件和2个完好的对比试件进行了竖向剩余承载力的试验研究。试验中记录了试件的荷载-位移关系曲线及名义应力-应变关系曲线,得到了试件的残余变形形态和竖向极限承载力。通过定义剩余承载力系数,得出剩余承载力系数与局部屈曲损伤变形量之间的函数关系式。试验结果表明:试件受压时,局部屈曲损伤部位成为明显的薄弱部位,加载过程中该部位的翼缘进一步扭曲,腹板出现严重的侧向鼓曲,试件表现为整体失稳破坏。随着冲击能量的增加,冲击荷载对构件的损伤程度增大,构件的竖向剩余承载力降低,剩余承载力系数与局部屈曲损伤变形量之间成线性关系。     

残余应力对等截面H型钢梁屈曲性能的影响研究

以有限元分析软件ANSYS为工作平台,基于非线性板壳有限元理论,采用壳单元对等截面H型钢梁考虑双重非线性的全过程分析,从而对其屈曲性能进行深入的研究。通过变化构件腹板、翼缘的残余应力峰值,从荷载一位移曲线、承载力、变形的发展等方面入手,分析了残余应力对等截面H型钢梁屈曲性能的影响,获得了一些有价值的结论。     

带翼缘十字形截面轴心受压构件的扭转失稳极限承载力分析

带翼缘十字形截面构件轴心受压时,极有可能发生扭转失稳。对于此类构件的扭转失稳,相关研究相对较少,设计时很容易被忽略,在工程应用时存在安全隐患。采用有限元方法,计入残余应力的影响,对带翼缘十字形轴心受压构件的失稳承载力进行了研究,考察了初始扭转角、扭转长细比、翼缘宽度、腹板高度、腹板厚度等参数对带翼缘十字形截面构件扭转失稳承载力的影响。结果表明:带翼缘十字形截面轴心受压构件在扭转失稳后不具备后屈曲性能;初始扭转会加速截面塑性区的发展,降低截面的刚度;在给定初始扭转缺陷和残余应力的前提下,构件的扭转失稳极限承载力仅与扭转长细比λω有关,与翼缘宽度、腹板高度、腹板厚度等几何参数没有直接关系。     

莱钢产轧制H型钢构件受力性能的理论与试验研究(Ⅳ)H型钢构件轴心受力性能的理论分析

对国产轧制H型钢截面构件进行了轴心受压承载力的理论研究。通过有限元方法 ,对国产轧制H型钢轴心受压构件的极限承载力进行了弹塑性和几何非线性的有限单元法理论分析 ,同时考虑了热轧型钢的残余应力和构件的初始缺陷。计算了 114根国产轧制H型钢轴心受压构件的极限承载力 ,得出国产轧制H型钢轴心受压构件极限承载力的主要公式。提出了便于设计人员应用的轴心受压修正公式。     

约束高强钢柱受火后轴压剩余承载力试验研究

设计了3根截面尺寸、长度均相同的Q550高强度钢柱,其中两根受到轴向约束,并对其进行了恒载作用下升温、降温的受火全过程试验,以及自然降温至室温后的轴压剩余承载力试验,对未受火的钢柱进行了常温下的极限承载力试验。研究了高温试验中钢柱的轴向位移-温度和中点侧向挠度-温度关系、极限承载力试验中钢柱的轴力-轴向位移和轴力-柱中点侧向挠度关系,并进行了有限元模拟。试验以及有限元模拟分析显示,若约束钢柱在高温过程中发生屈曲,则降温后钢柱会有明显的残余弯曲变形,并且柱中截面会产生比初始残余应力更为显著的残余应力,从而显著降低钢柱的剩余承载力和轴向刚度。试验结果与有限元分析结果吻合较好,验证了有限元分析模型的有效性。     

H型钢梁-H型钢柱偏心节点局部屈服荷载承载力的力学行为研究

针对槽形钢折板补强H型钢梁-H型钢柱的偏心节点,研究了节点局部屈服荷载承载力的力学行为。通过建立5种可能形成的塑性屈服破坏模型,利用屈服线理论,推导出H型钢梁-H型钢柱偏心节点的局部屈服荷载承载力计算公式。取包含梁受拉翼缘在内的节点构件(1/4模型)作为试件,进行了6组拉伸加载试验,验证偏心节点的弹塑性响应。通过对应变分布和翼缘平面外残余变形响应的分析来验证塑性屈服破坏模型的准确性。     

单面焊接H型钢局部荷载作用处的应力和补强

腹板和翼缘采用单面角焊缝连接的焊接H型钢 ,承受局部荷载作用时存在接头传力偏心的问题。通过对比试验数据 ,验证了所建立的单面焊H型钢有限元计算模型 ;对局部受力部位的焊缝和板件进行了应力计算 ,对偏心影响作了定量分析。根据试验和计算结果 ,提出了柱与牛腿相连焊缝的有效长度和柱腹板的应力计算公式 ,并讨论了柱腹板的补焊范围。     

Experimental investigation of stress and damage characterization of steel beam buckling using magnetic memory signals

Metal magnetic memory is a new passive nondestructive method for assessing stress conditions that can be used in the detection of early damage in ferromagnetic materials. To obtain the signal characteristics of steel beams, the normal components of the surface‐spontaneous magnetic signals of a flange and web of Q235B I‐steel beams were measured using four‐point flexural tests under different loads. The variation in the normal component and its gradient were analyzed. The results show that the normal component can reflect the stress distribution of the flange, a significant decrease in the normal component of the flange, and a reversal of the normal component of the web can predict the instability of a beam. The location of a concentrated load on a steel beam can be determined by the highest value of the magnetic signal and the peak–peak value of the magnetic gradient. Finite element software was employed to calculate the von Mises stress, and a qualitative relationship between the distribution of the normal component and the distribution of the von Mises stress was obtained. A quantitative correlation between the applied stress and the average value of the normal component of the flange was developed. Quantitative analyses of the applied stress should consider the dimensional effect of different specimens. A new method is proposed to estimate the location of the stress concentration and to evaluate the degree of damage using a gradient curve, and several parameters are defined to characterize the metal magnetic memory signal. These characteristic parameters may reflect the degree of damage and the range of loads. Copyright © 2015 John Wiley & Sons, Ltd.     

残余应力分布对焊接不锈钢工字形截面梁整体稳定性能的影响

焊接残余应力导致不锈钢梁截面纤维过早达到屈服,并严重降低不锈钢梁的抗弯刚度。为了研究残余应力对焊接工字形不锈钢梁侧扭屈曲的影响,根据目前被广泛采纳的不锈钢工字形截面残余应力分布模型,采用有限元方法,对残余应力分布模型的主要因素进行参数化分析,研究这些因素对不锈钢梁侧扭屈曲的影响,使对焊接工字形不锈钢梁的整体稳定性能的研究更加完善。结果表明:翼缘残余压应力峰值对不锈钢梁侧扭屈曲的影响最为显著。     

住宅钢结构梁翼缘材料削弱型节点的有限元分析

提出一种利用低屈强比钢实现住宅钢结构节点梁翼缘削弱的新方法。采用非线性静动态有限元方法,分析和比较梁翼缘材料削弱前后节点的极限承载能力和滞回性能,研究梁翼缘削弱位置和削弱长度等对节点承载能力、塑性铰发生位置、节点抗震性能等的影响。分析表明:梁翼缘材料削弱会造成节点承载能力小幅度降低,并使节点局部应力重分布,实现塑性铰外移;梁翼缘削弱后,节点的滞回曲线更为饱满,节点耗能性能和延性性能增强;梁翼缘削弱位置和削弱长度的变化对节点承载能力和抗震性能都有一定影响,需要对削弱参数进行综合考虑。     

钢-混凝土连续组合梁受力性能的有限元分析

为了分析钢-混凝土连续组合梁混凝土翼板的厚度、钢梁翼缘厚度、腹板高度和厚度等参数的变化对梁的应力和挠度的影响,利用ANSYS有限元软件,对两跨连续组合梁进行非线性瞬态分析,将计算结果和实测结果进行比较,验证了该模型的有效性。通过变换组合梁混凝土翼板的厚度,钢梁翼缘的厚度,腹板的厚度和高度,分析得出对梁的应力和挠度的影响强弱依次为：混凝土板厚,腹板高度,钢梁上下翼缘的厚度,腹板的厚度。     

Experimental load-carrying capacity evaluation of thermal prestressed H beam with steel brackets

To improve the load-carrying capacity of steel structures there are mainly two methods of using cover-plate which are the preflex method and multi-stepwise thermal prestressing method. However a prestress applied to the top flange of H beam is less than the bottom flange because these two methods have small eccentricity. It is necessary to develop an advanced feature of prestressing method which efficiently increases load-carrying capacity and prestressing efficiency. Therefore this study proposes a cover-plate prestressing method with increased sectional stiffness and prestressing efficiency, called multi-stepwise thermal prestressing with steel brackets. To evaluate the prestressing efficiency and load-carrying capacity of the proposed method, prestressing application tests and static loading tests were conducted on three H beams. The multi-stepwise thermal prestressing method with the steel brackets had higher displacement induced to the H beam and higher tensile stress in the top flange than in a case without the steel brackets. Also, when prestress is applied, the tensile stress in the cover-plate significantly decreased with the installation of the steel brackets. The static loading tests showed that the installation of the brackets increased the stiffness, the yield load, and ultimate load of the structure, compared with an unreinforced girder, which meant higher load-carrying capacity than a conventional thermal prestressed structure without brackets.     

输电线路大跨越钢管塔法兰盘连接试验及研究

钢管法兰连接节点的设计研究是大跨越高塔设计的重要组成部分。对于某些重大的跨越高塔,由于荷载的大幅增加,法兰节点按常规计算方法得到的承载能力不够精确,使得设计人员难以准确把握实际结构的受力状态,设计的风险较大,而法兰节点的准确合理设计是保证结构安全的重要环节。以舟山与大陆联网工程中的370m大跨越塔为背景,对内侧螺栓连接法兰和外侧螺栓连接法兰进行节点极限承载力拉伸试验,并建立精确的有限元分析模型,研究法兰节点的力学行为、应力分布以及弹塑性的破坏过程,证明内法兰与外法兰都具有很高的安全裕度,可以作为大跨越钢管塔的法兰节点设计的一种参考。     

Proposed residual stress model for roller bent steel wide flange sections

The manufacturing process of structural wide flange steel sections introduces residual stresses in the material. These stresses due to hot-rolling or welding influence the inelastic buckling response of structural steel members and need to be taken into account in the design. Based on experimental data standardized residual stress models have been proposed for inclusion in inelastic buckling analyses. By incorporating these residual stress models their effect on the resistance of beams and columns can be obtained. Residual stress models for roller bent steel sections are currently not available. Roller bent wide flange sections are manufactured by curving straight members at ambient temperature. This manufacturing technique, which is also known as roller bending, stresses the material beyond its yield stress, thereby overriding the initial residual stresses prior to bending and generating an entirely new pattern. This paper proposes a residual stress model for roller bent wide flange sections, based on earlier conducted numerical investigations which were validated by experimental research performed at Eindhoven University of Technology. The proposed residual stress model can serve as an initial state of a roller bent steel section in fully non-linear finite element analyses to accurately predict its influence on the inelastic buckling response.     

不设加劲肋的钢梁腹板高厚比限值研究

分析处于统剪状态的钢梁腹板临界应力,综合考虑弯曲应力和局部压应力及翼缘时腹板的约束作用,得出不需设呈置加劲肋时腹板的高厚比限值计算公式,并给出便于设计应用的硬板高厚比限值简化计算公式．