胶合木梁柱螺栓-钢填板节点转动性能研究

通过4组22个胶合木梁柱螺栓-钢填板足尺节点试件的单调和低周反复加载试验以及有限元数值模拟研究梁柱螺栓-钢填板节点的转动性能。试验研究表明,胶合木梁柱螺栓-钢填板节点性能主要取决于螺栓和螺孔周边木材的承压能力;节点加载初期的螺孔间隙和加载后期木材横纹裂缝张开均会导致节点刚度显著下降;同等条件下,节点初始刚度和极限弯矩随螺栓直径的减小而减小,节点初始刚度随螺栓边距的增加而减小。对试件进行有限元分析结果表明,基于有限元分析软件建立的节点三维实体模型对于节点的初始刚度和极限弯矩有较好的模拟精度(误差20%以内)。此外,模型参数分析表明,在更大取值范围内(螺栓直径12~28 mm,螺栓边距30~70 mm),螺栓直径和边距对节点性能的影响与试验结果一致。     

Study on rotational behavior of bolted glulam beam-to-columnconnections with slotted-in steel plates

通过4组22个胶合木梁柱螺栓-钢填板足尺节点试件的单调和低周反复加载试验以及有限元数值模拟研究梁柱螺栓-钢填板节点的转动性能。试验研究表明,胶合木梁柱螺栓-钢填板节点性能主要取决于螺栓和螺孔周边木材的承压能力;节点加载初期的螺孔间隙和加载后期木材横纹裂缝张开均会导致节点刚度显著下降;同等条件下,节点初始刚度和极限弯矩随螺栓直径的减小而减小,节点初始刚度随螺栓边距的增加而减小。对试件进行有限元分析结果表明,基于有限元分析软件建立的节点三维实体模型对于节点的初始刚度和极限弯矩有较好的模拟精度（误差20％以内）。此外,模型参数分析表明,在更大取值范围内（螺栓直径12~28mm,螺栓边距30~70mm）,螺栓直径和边距对节点性能的影响与试验结果一致。     

自攻螺钉参数设置对胶合木梁柱节点受力性能的影响

采用自攻螺钉对胶合木梁柱节点进行横纹加强可有效传递木材的横纹拉应力和顺纹剪应力,从而延缓木材开裂、提高节点性能。为了研究自攻螺钉的布置间距、直径和个数等参数对加强节点受力性能的影响,对4组采用不同布置间距、直径和个数的自攻螺钉加强胶合木螺栓连接梁柱节点进行单调和低周往复加载试验,得到各组节点的刚度、延性、承载力、破坏模式和抗震性能。结果表明：自攻螺钉个数增加、直径增大,节点的承载力、破坏转角、延性系数以及节点总耗能增大;自攻螺钉布置间距的变化对节点在单调荷载作用下的承载力和延性系数无明显影响;而节点在往复荷载作用下时,随着自攻螺钉布置间距的减小,节点承载力和总耗能降低。     

胶合木预应力套管螺栓群连接梁柱节点受弯承载力及参数分析

采用有限元软件ABAQUS建立了钢插板胶合木预应力套管螺栓连接梁柱节点的三维有限元模型,分析了节点的受弯特性,并通过与试验结果的对比验证了模型的合理性。有限元分析结果表明,套管梁柱节点摩擦阶段的抗弯刚度较传统节点的有明显提升,基于分析结果,对钢管与钢板摩擦力、钢管外径和壁厚、高强螺栓直径和等级、木材强度和厚度等参数对套管节点抗滑移刚度的影响进行了进一步分析。依据分析结果,建议高强螺栓的预拉力值介于规定值的100%~110%之间,钢管与钢板间摩擦系数不小于0.3,钢管径厚比的合理取值范围为6~10,相应的初始应力比在0.4~0.6之间。研究成果可为胶合木构件套管螺栓连接节点的设计提供参考。     

自攻螺钉增强胶合木梁柱螺栓节点受力性能试验研究

设计制作了9个胶合木梁柱螺栓节点试件,其中7个螺栓节点采用自攻螺钉进行增强。进行了单调和低周反复加载试验,研究胶合木梁柱螺栓节点采用自攻螺钉增强后的受力性能。试验研究表明,胶合木梁柱螺栓节点易产生木材撕裂破坏,采用自攻螺钉增强后的节点由于自攻螺钉咬合力作用,有效抑制了木材纹理的开裂;当螺栓边距、端距小于GB/T50708—2012《胶合木结构技术规范》限值时,节点试件的承载力及延性仍有明显提高,其中,螺栓直径20 mm的节点试件承载力最大提高了112%,螺栓直径14 mm的节点试件承载力提高了81%。     

自攻螺钉增强胶合木梁柱螺栓节点的抗弯承载力计算

现有研究表明,自攻螺钉能有效抑制木材纹理的开裂。主要研究经自攻螺钉增强后的胶合木梁柱螺栓-钢填板节点的抗弯承载力计算方法,通过在木梁自由端施加集中力,基于自攻螺钉的增强作用,把梁柱节点螺栓处产生的弯矩分解成沿木材纹理方向的一对力偶矩与垂直木材纹理方向的一对力偶矩,并结合Johansen屈服模式进行力偶的计算。得出的理论计算值与经自攻螺钉增强后的节点实测值进行比较,误差在10%之内,很好地解决了自攻螺钉增强螺栓节点的抗弯承载力理论计算问题。     

新型胶合竹梁柱节点抗侧性能试验研究

进行了钢填板螺栓连接和新型外包钢板螺栓连接胶合竹梁柱节点的单调加载试验,通过节点的弹塑性刚度、屈服荷载、极限荷载和延性系数,分析了两种胶合竹梁柱节点的抗侧性能。试验结果表明,钢填板螺栓节点存在初始滑移,初始刚度较小,一旦出现螺栓截面的劈裂裂缝,承载力立即下降。外包钢板螺栓节点的外包钢板对节点起到较好的约束作用,出现劈裂裂缝后承载力还有上升空间。由此可见,采用外包钢板螺栓连接是增强胶合竹梁柱节点抗侧性能的有效措施。     

基于Abaqus的木结构螺栓节点刚度有限元分析

为分析木结构中对螺栓节点刚度的主要影响因素,首先基于Abaqus软件针对试验节点建立有限元模型,考虑木材的材料非线性、装配体间接触对、边界约束条件设置等关键问题,对比发现有限元分析方法是可行的。在此基础上,扩充模型参数,进一步分析螺栓直径与侧材厚度比值、螺孔与孔壁间隙、节点安装偏差以及螺栓的预紧力对木结构螺栓节点刚度的影响,研究成果可为螺栓节点应用于木结构中提供技术参考。     

带翼缘钢填板-螺栓连接胶合木梁-柱节点转动性能试验研究

针对钢填板-螺栓胶合木梁-柱连接节点易发生木材横纹劈裂脆性破坏的问题,提出在钢填板上下端增设翼缘以降低木材横纹拉应力或约束木材横纹裂缝扩展,形成带翼缘钢填板-螺栓连接胶合木梁-柱节点形式。通过对其进行单调加载试验,获得了该连接节点的弯矩-转角关系曲线,对比分析了该类连接节点和采用不同加固技术的普通钢填板-螺栓连接节点的受弯承载力。研究表明：带翼缘钢填板-螺栓连接节点具有良好的变形能力,其相对受弯承载力较普通钢填板-螺栓连接节点提高最多可达129%,且高于采用自攻螺钉、碳纤维布和交叉胶合木等技术加固的普通钢填板-螺栓连接节点的受弯承载力。     

胶合木钢填板-螺栓节点抗弯刚度研究

为明确胶合木钢填板-螺栓节点的半刚性特征，进行了考虑螺栓行距、列距、列数和胶合木截面高度等参数变化的胶合木钢填板-螺栓节点抗弯试验。得到节点抗弯刚度后与欧洲木结构设计规范((BSEN 1995-1：2004))、日本木质构造接合部设计手册里节点抗弯刚度公式计算结果进行对比，结果表明规范公式计算的节点抗弯刚度均小于试验值，通过修正规范公式可以得到更加准确的计算结果。针对日本木质构造接合部设计手册的公式引入了滑移系数修正值和顺纹嵌入刚度修正值，修正后的公式准确度高，在胶合木结构设计的过程中可以用于计算节点的抗弯刚度并得到节点抗弯刚度折减系数。     

木销半榫节点转动性能试验研究与有限元分析

为研究木销半榫节点平面内的转动性能和节点区域木材损伤演化,通过木销半榫节点试件的单调加载试验和有限元分析研究了此类节点平面内的转动性能.试验研究表明,加载初期预钻孔附近木材会发生横纹劈裂破坏,随着荷载不断增加,榫头变截面处木材会出现顺纹受拉破坏.节点有限元分析结果表明,采用弹塑性损伤模型建立的有限元模型对于节点刚度和受...     

Prediction models for the initial rotational stiffness and ultimate plastic moment for a double split tee connection

As a partially restrained connection, a double split tee connection has demonstrated various behavioral characteristics based on the combination of T-stub thickness, high-strength bolt gauge distance, and beam and column stiffness ratio, among other characteristics. Accordingly, many researchers have proposed an analysis model that would determine the behavioral characteristics, stiffness, and strength of a double split tee connection by selecting T-stub thickness and high-strength bolt gauge distance as parameters. However, such a model has not yet been proven to be accurate due to complicated stress distribution, contact and bearing phenomena, as well as prying action on high-strength bolts. Therefore, this study proposed an improved prediction model for the initial rotational stiffness and ultimate plastic moment to implement double split tee connections in the domestic steel structures market. Toward this end, this study performed the three-dimensional nonlinear finite element analysis, and validated the proposed model by comparing and reviewing its test results from the works of other researchers.     

钢柱脚锚栓连接受剪性能试验研究

对锚栓连接受剪性能进行试验研究,制作了5组共15个试件,考虑了锚栓的直径、柱底板厚度和底板锚栓孔径与锚栓直径之差的影响。锚栓连接受剪试验的荷载 位移曲线呈现2个转折点,可近似分为3个阶段：弹性阶段、滑移阶段和强化阶段,以锚栓基本形成塑性铰与锚栓孔壁和锚栓顶紧两个状态作为分界点。试验结果表明,柱底板厚度越大,锚栓连接受剪承载力设计值和界面抗滑移刚度越小;锚栓孔径和锚栓直径之差对滑移阶段的长度有显著的影响,对承载力影响较小。以试验荷载 位移曲线的第一转折点对应的荷载作为锚栓连接的受剪承载力设计值,提出了计算式,同时提出锚栓连接极限承载力的计算公式。     

Load–deflection behaviour of thin-walled plates with a single bolt in shearing

This paper presents an experimental, numerical and analytical study of the behaviour of thin-walled plates connected by a single bolt under shear. Eighteen tests were carried out to provide detailed data of load–deflection and load–strain curves for validation of the finite element simulation model. The validated finite element model was then used to perform a comprehensive set of parametric studies to investigate the effects of different design parameters on the connected plate behaviour, including initial stiffness, ultimate resistance and maximum deformation at the ultimate resistance. It was found that the stiffness and ultimate resistance could be predicted accurately by using existing methods. The analytical study therefore focused on developing a method to calculate the maximum plate deformation (hole elongation) at the ultimate resistance. Based on the parametric study results, methods of calculating the ultimate deformation were proposed, based on different failure modes of the connection.     

木材非线性受力行为的表征方法研究进展

木材非线性受力行为的表征方法对木结构构件和节点受力行为的有限元分析具有至关重要的影响。为此,从木材失效行为的判别依据和材料本构模型两方面对该领域的研究进展进行了梳理总结。结果表明,已有的强度准则各有其局限,难以全面地反映木材复杂的失效行为。在数值模拟中常需要结合不同强度准则以提高预测模型的计算精度。弹塑性本构模型能够合理反映木材在压应力作用下的硬化行为,并且能够描述木材出现的残余变形,但该模型难以描述木材在拉应力和剪应力作用下的刚度退化和强度软化行为。弹性损伤理论可在一定程度上反映材料的软化行为和反复加载过程中的刚度退化行为,但该理论不能考虑材料的塑性变形。基于上述理论建立的黏聚区单元的初始刚度和相邻单元长度对计算结果具有显著的影响。三维弹塑性损伤模型已经被应用于木结构构件和螺栓连接节点的有限元分析中,此类模型能有效反映构件和节点区域木材的损伤演化规律。随机损伤本构模型和非局部化损伤模型是未来的发展趋势。     

The effect of axial beam force on moment–rotation curve of top and seat angels connections

Bolted top and seat angle connections are mainly designed to sustain gravitational loads of simply supported steel beams. However, the inherent flexural resistance of such connections may not be ignored when an accurate analysis of semirigid steel frames is desired. Current research aims at studying moment–rotation behaviour of this type under combined moment and axial tension force. Several refined three‐dimensional finite element models are created based on the previous experimental studies, and their accuracy is examined trough a comparison to test results from previous experimental studies. This study showed that the axial tension force reduces the connection initial stiffness and moment capacity. Based on the results obtained from analysing a series of finite element models under combined axial tension and moment loading, an equation is presented to estimate the affected moment–rotation response of such connections in terms of the connection geometrical properties, its moment–rotation response in the case of zero axial force and an expected axial tension force. Copyright © 2009 John Wiley & Sons, Ltd.     

Effect of shear force on the initial stiffness of top and seat angle connections with double web angles

This study focused on the moment-rotation behavior of bolted top and seat angles with double web angle connections, especially the initial stiffness of this type of connection under the combination of shear force and moment. Several 3D parametric finite element models are presented in this regard, with the geometrical and mechanical properties of connections are as parameters. In the models, all the connection components such as beam, column, angles and bolts are modeled using eight node brick elements. The effects of all component interactions, such as slippage of bolts and frictional forces, are modeled using a surface contact algorithm, and to evaluate the connection behavior more precisely, bolt pre-tensioning is applied on the bolts shanks as the first load case. The results of numerical modeling are compared with test results of experiments that have been done by researchers, and show good agreement with them. To evaluate the effect of shear force on the behavior of such connections, several models were analyzed under different magnitudes of shear force, and the results of the analyses showed that the shear force has a reducing effect on the initial stiffness of bolted angle connections. Therefore, an equation is proposed to determine the reduction factor of a connection’s initial stiffness in terms of the connection’s initial stiffness and yield moment in the case of no shear force, and any expected shear force that might be applied.     

不同构造特征的H形钢梁-柱半刚性连接节点抗震性能试验研究及有限元分析

通过对6个具有不同构造特征和几何尺寸的H形钢梁-柱半刚性连接试件进行拟静力试验和有限元分析,得到节点弯矩-转角（M-θ）滞回曲线及M-θ骨架曲线,分析了试件的极限弯矩、连接初始刚度、延性、耗能性等性能。研究结果表明：对于几何尺寸相近的梁柱端板连接,柱强轴方向翼缘-端板连接的极限弯矩及初始连接刚度远高于柱弱轴方向的腹板-端板连接,且后者的延性也比较差;采用弱轴方向的端板连接,应在腹板的两个方向同时设置加劲板,以保证有足够的连接强度和延性;在柱翼缘设置抗剪托板对于梁柱外伸端板连接性能无明显影响,而且延性还有降低趋势。     

带齿夹板钢木连接节点受力机理

为解决胶合木网壳螺栓连接节点初始刚度低、木梁螺栓孔易发生劈裂的问题,提出一种带齿夹板钢木连接节点。通过试验研究了带齿夹板节点(JD-2)在单调荷载作用下的力学性能和破坏模式,并与同尺寸下不含钢齿的普通夹板节点(JD-1)进行对比分析。为深入研究带齿夹板节点的受力机理,对带齿夹板节点进行有限元模拟。结果表明:JD-1的破坏模式为木梁沿螺栓孔水平连线方向的横纹劈裂破坏,JD-2的破坏模式为夹板屈服破坏; 与JD-1相比,JD-2的初始刚度提高了47.18%,极限承载力提高了31.4%,延性系数提高了19.83%; 钢齿与木梁之间的机械咬合作用可以有效减少木梁螺栓孔初始间隙对节点刚度的不利影响; 在弯矩与剪力联合作用下,荷载通过钢齿及螺栓共同传递给木梁,减少了木梁螺栓孔的应力,因此延缓了木梁螺栓孔的开裂; 随着夹板翼缘厚度的增加,节点的受弯性能呈现增大的趋势; 增加夹板布齿率,木梁螺栓孔受到螺栓挤压应力减小,钢齿阻止夹板与木梁之间的相对滑动能力增强,建议夹板布齿率取0.46%～0.65%。