钢结构箱形柱与梁异型节点抗剪承载力分析

基于对钢结构箱形柱与梁异型节点形式及受力性能的分析,建立异型节点域的受剪计算模型,并推导节点域在压弯情况下的抗剪承载力计算公式。通过对箱形柱与工字梁和箱形梁异型节点模型的低周反复加载试验,研究轴压比和核心区高度对节点域抗剪承载力的影响,得到节点域的剪力-剪应变滞回曲线;从试验模型的滞回曲线可以看出,异型节点域以剪切变形为主,且具有良好的延性和抗剪承载能力。试验结果与计算分析表明,节点域在小核心区发生剪切屈服,提出的节点域抗剪承载力计算公式与试验结果比较吻合。     

基于多尺度模型的襄阳东津站铸钢节点动力弹塑性分析

针对关键节点的细部分析,采用从整体模型中隔离出节点,将整体模型与节点模型分别独立计算的方法,在节点域施加的边界条件往往与实际情况相差较大。应用多尺度建模技术对东津站屋盖铸钢节点进行动力弹塑性分析。屋盖杆件采用梁单元建模,关键节点采用实体单元进行精细化建模,并通过自由度约束方程对梁单元和实体单元进行多尺度连接,从而准确反映节点域的边界条件。分别采用多尺度建模和隔离体建模进行对比分析:在结构整体地震动响应方面,两者的计算结果基本一致,多尺度建模仅对节点域相邻区域的杆件有一定影响;在节点域的计算分析方面,采用隔离体的节点分析结果偏于保守。研究表明,多尺度建模技术精确描述节点边界条件,是分析复杂结构关键节点的一种有效手段。     

节点域斜加劲肋设计计算方法

我国现行钢结构设计规范与规程对梁柱节点域的抗剪能力提出了具体的要求,并指出当节点域抗剪能力不足时可设置斜向加劲肋。但是却没有给出所设置的斜加劲肋的计算办法。采用有限单元法对考虑了斜肋板宽厚比、腹板宽厚比、节点域高宽比、柱翼缘宽厚比等多种影响因素的节点域模型进行了屈曲后强度计算,分析了各种不同情况下的节点域的变形及应力分布,提出了有斜加劲肋的节点域的等效计算模型及计算公式,并推导了门式刚架节点域斜加劲肋的设计计算公式。     

加劲板对钢空腹夹层板剪力键节点静力特性影响分析

剪力键节点域是保证钢空腹夹层板空间协同工作的关键节点。为研究加劲板对剪力键节点域静力特性的影响,基于通用有限元分析软件,建立4组考虑材料非线性的节点域平面受剪状态数值模型。分析了设置加劲板对节点域受力及变形状态的影响,并选取加劲板宽度、方钢管厚度、剪力键高度作为变量进行参数化分析。分析结果表明,加劲板可以有效降低节点域方钢管的应力,保证节点域整体变形的特性,避免出现反弯点。根据不同因素的影响程度,发现加劲板的宽度对节点域的静力性能影响最大,提出了加劲板设置的合理尺寸范围的建议值,分析结论可为类似工程应用提供参考。     

影响方钢管柱-H型钢梁不等高梁节点域性能的参数分析

为探究影响方钢管柱-H型钢梁外加强环式不等高梁节点域力学性能的参数,以梁高比、柱宽厚比、轴压比、梁翼缘宽厚比、梁柱宽厚比和节点域高宽比为分析参数,采用有限元分析软件ABAQUS,在对比已有试验结果验证有限元模型可靠性的前提下,对节点模型进行了单向位移加载下非线性数值模拟分析。研究结果表明:柱宽厚比对不等高梁节点域剪切初始刚度有明显影响;梁高比、柱宽厚比和梁翼缘宽厚比对节点域的变形能力有一定影响;梁高比和柱宽厚比对不等高梁节点域的剪切承载力影响较大。     

外加强环不等高H型钢梁-方钢管柱节点受力性能有限元分析

在外加强环不等高H型钢梁-方钢管柱节点抗震性能试验研究的基础上,采用有限元分析软件ABAQUS,建立了考虑不同参数影响的三维实体模型并进行了非线性有限元分析。三维实体模型分析得到的有限元结果与试验结果吻合良好,有限元模型能够较高精度地模拟节点的受力行为。研究表明：节点的破坏形式分为整体节点域剪切破坏和局部节点域剪切破坏两种;节点单侧框架柱端部弯矩增大系数是节点域形成不同破坏模式的重要控制参数,两种破坏模式的分界线是节点单侧框架柱端部弯矩增大系数约为0.92;方钢管柱的宽厚比是影响节点域屈服剪力和塑性剪力的主要因素,梁截面高度比对节点域受剪承载力影响较大,而节点域高宽比对节点域屈服剪力和塑性剪力影响并不明显。     

节点刚域对钢管输电塔主材受力的影响

为了研究节点刚域对主材受力的影响,将主材及其相关节点视为微观尺度模型,采用壳单元离散,将输电塔的其余部分作为宏观尺度模型,采用梁/杆单元离散。根据平截面假定推导了位移约束方程来实现微观尺度模型和宏观尺度模型的连接。6座输电塔的多尺度有限元分析结果表明:节点刚域对输电塔主材的轴力影响很小,而对弯矩影响较大。因此,对于弯曲应力与轴向应力比例较大的主材,可以考虑采用多尺度模型来分析,以考虑节点刚域对主材受力的影响。     

节点刚域对框架结构抗侧刚度的影响

节点刚域对框架结构的刚度和构件内力设计值的选用有一定的影响。为了研究节点刚域对框架结构抗侧刚度影响的机理,根据框架结构的组成,分为平面框架和框筒两个层次进行。首先利用Abaqus实体单元模型校准Etabs杆单元加刚臂模型。然后,变化参数如平面框架和框筒的高宽比以及竖向刚域、水平刚域、全刚域的施加等,利用Etabs模型研究节点刚域对框架抗侧刚度的影响。最后,通过实际工程分析,验证了节点刚域对结构抗侧刚度影响的适用性,为工程设计提供参考。     

门式刚架端板连接节点弯矩-转角曲线计算模型

进行了8个门式刚架端板连接节点的有限元分析,得出节点构造形式、端板厚度等因素对节点受力性能的影响规律.提出了门式刚架端板连接节点的弯矩-转角曲线计算模型.该模型考虑了节点域斜向加劲肋的作用,也考虑了节点域局部屈曲的发展过程和节点组件间的相互作用.通过与有限元分析及试验数据对比,表明该模型能够很好地反映门式刚架端板连接节点的受力性能,初始刚度和极限承载力等关键指标吻合较好.     

节点域强度对双拼梁与柱连接节点抗震性能的影响

一种新型装配式梁柱节点由柱与双肢拼合热轧槽钢梁组合而成.为了研究这种新型节点的节点域强度对抗震性能的影响,使用ABAQUS有限元软件建立节点模型.在不同螺栓间距下,通过改变节点域厚度得到节点模型的耗能能力、破坏特征、骨架曲线、滞回曲线等力学性能,并与普通工字梁节点进行对比分析.结果表明:双拼梁在未布置螺栓时易发生单肢槽钢失稳,影响节点受力,布置螺栓可以有效改善失稳情况;当螺栓间距小于梁截面高度的1.25倍时,节点的受力性能与普通工字梁节点的受力性能接近,因此,在合理的螺栓间距范围内,节点域厚度可按普通工字梁节点域设计;当螺栓的间距为梁截面高度的1.25～2.50倍时,节点域的实际厚度可取设计厚度的0.8～1.0倍.     

方钢管混凝土节点核心区剪切试验及其数值模拟

为研究方钢管混凝土节点核心区的受力性能,在分析梁柱节点核心区受力特征的基础上,设计了方钢管混凝土节点核心区的直接剪切试验。试验装置简单,能够确保核心区发生剪切破坏,有效反映其受力特征。通过改变钢材及混凝土的强度、节点几何形状及加载方向等参数,完成了13个方钢管混凝土节点核心区试件的单调和往复剪切加载试验,得到了节点剪切破坏特征、荷载-位移曲线等结果,分析了相关参数的影响。在试验结果的基础上,利用理想弹塑性模型模拟钢材,并利用修正了剪力传递系数的固定角弥散裂缝模型模拟混凝土,提出了适用于一般节点核心区分析的高效精细有限元数值模拟方法。模拟结果与试验结果吻合良好,可为复杂组合结构的非线性分析提供参考。     

Modeling the panel zone in steel MR frames composed of built-up columns

This paper proposes an analytical model for the panel zone of connections of steel moment-resisting frames (SMRFs) composed of built-up columns with double sections and a vertical continuity plate. Panel zone in these connections consists of a middle panel, which is the vertical continuity plate, and two side panels, which are the webs of double sections of the column. Since the general behavior of these frames is governed by deformation of the middle panel, this panel is assumed as the primary one and the two side panels are assumed to be secondary. The column cover plates connecting the double sections and vertical continuity plate play an important role in providing compatibility of deformations. The new model proposed in this study is based on the previously developed models for the panel zones of connections in which the webs of beam and column are in the same plane, however, a number of refinements are introduced to capture the behavior of this type of connections. This quadri-linear model can be used for monotonic loading and accounts for both shear and bending deformations of panel zone. The results of this model are compared to those of finite element (FE) models verified by full scale experiments. The proposed model shows a good agreement, especially in elastic range, with the FE results. The results of FE analysis for important parameters affecting the panel zone behavior have also been compared to those obtained from the model in order to confirm the proposed model.     

节点域对钢框架梁柱连接受力性能的影响

在对30层钢框架进行预设计的基础上,选定梁柱栓焊连接试件进行有限元分析。经过对该连接试件及其节点域的滞回性能和应力分布进行有限元分析后得出,节点域具有非常稳定的非线性变形能力和耗能能力,对连接的塑性转动能力贡献较大。建议设计中允许节点域发生非线性变形,以降低对连接的塑性转动能力要求。节点域的剪应力在节点域中心最高,向四角逐渐降低,节点域剪切屈服后,几乎所有的柱轴力都转移到柱翼缘上。建议设计时选用翼缘宽大的柱截面,以保证柱翼缘能够承受因节点域剪切屈服而由柱腹板转移的压力。     

钢管混凝土柱、钢筋混凝土板、钢梁连接节点的抗震性能:节点模型

基于已有试验和数值计算结果,研究了钢管混凝土柱(CFST)和钢梁的复合节点模型。采用参数研究法利用有限元分析方法(FEA)分析了节点连接处的弹性剪切刚度和剪切变形,给出了复合节点连接处包含弹性剪切刚度、剪切强度、剪切变形和滞后准则的迟滞模型。该迟滞模型用于整合基于纤维的节点宏单元,节点宏单元通过有限元方法和试验结果得到证实。研究了CFST节点和宏单元框架的整体和局部性能。该模型计算精确,建模方法适当,能够用于大尺寸和复杂组合结构的抗震性能分析。     

Cyclic behaviour of post-Northridge WUF-B connections

The purpose of this study is to evaluate the cyclic behavior of post-Northridge Welded Unreinforced Flange-Bolted web (WUF-B) connections made using new notch tough welding materials and welding procedures, and a modified access hole. Since no WUF-B connection test results were found which satisfy the minimum design and detail requirements of the 2002 AISC Seismic Provisions for Structural Steel Buildings, this study made three full-scale test specimens of WUF-B connections according to the provisions. The main variable of the specimens was the ratio of the panel zone strength to the connected beam strength (panel zone strength ratio). Quasi-static cyclic testing was conducted. This study found that post-Northridge WUF-B connection specimens having a stronger panel zone experienced more significant slip between the bolted shear tab and the beam web. It was observed that the slip caused stress concentrations in and around the access hole, resulting in connection failure. The WUF-B connection specimen having the weakest panel zone did not, however, experience excessive slip between the bolted shear tab and beam web. Moreover, this WUF-B specimen could not achieve the required beam strength. This study observed that post-Northridge WUF-B connections with a panel zone strength ratio ranging from 0.9 to 1.6 provides a drift ratio exceeding 0.2. This drift ratio is required for satisfactory performance of the connections of Intermediate Moment Frames. Furthermore, this study proposed an analytical model for post Northridge WUF-B connections having different panel zone strength ratios.     

Simplified uni-axial hysteretic damage model for panel zone of structural steel under earthquake loads

In structural systems, it is a very important issue to predict damage levels of structural components subjected to earthquakes. To appreciate ultimate behaviors and fracture mechanism on the panel zone of structural steels under earthquake loads, it is essential to comprehend damage levels quantitatively. Thus, simple damage models are needed to predict structural components behaviors for random earthquakes effectively. This study proposes a simplified uni-axial hysteretic damage model for panel zone, which is applicable to multi-axial cyclic loading. To confirm the validity of the model, experimental tests are performed under the cyclic shear loading with constant or variable axial loading. The results from the tests are compared with those of the proposed hysteretic model considering the effect of damage. Though limitations are given to the application of this model, this model can predict well the hysteretic behavior of general panel zone applied to multi-axial cyclic loading.     

Seismic analysis of inelastic moment‐resisting frames Part II: Energy dissipation in deformable panel zones

The simple analytical method developed in the companion paper is applied to study the dynamic behavior and energy dissipation of inelastic structures with panel zone deformation using rotational springs. Both shear deformation and inelastic behaviors of the panel zone are modeled using rotational springs to capture the actual vibration characteristics of the overall structural responses. The modified force analogy method with static condensation proposed in the companion paper is employed to study the effects of panel zone deformation on the dynamic behavior of inelastic structures, while rigid end offsets are also included to give a more accurate structural model. Based on this proposed analytical method, numerical simulation is first performed to study the responses of a one‐story one‐bay moment‐resisting frame. Results show that rigidity of panel zones plays a major role in the overall structural responses during earthquake excitations. Numerical simulations are then performed on a multi‐degree of freedom structure to demonstrate the use of the proposed method. Comparison of results between modeling structures with various panel zone rigidities and yield moments in the rotational springs shows that significant differences in both structural responses and energy dissipations exist between the models, and therefore the effects of panel zone deformation should be considered in dynamic analysis. Copyright © 2007 John Wiley & Sons, Ltd.     

钢梁柱节点域受力性能影响因素的有限元分析

利用大型通用有限元软件，建立有限元模型，在单调加载作用下，分析了柱翼缘以及横向加劲肋的厚度变化对节点域受力性能的影响，得出相关的结论。