【作者】 闫亚杰；

【导师】 雷宏刚；

【作者基本信息】 太原理工大学 ， 结构工程， 2013， 博士

【摘要】 平板网架结构作为空间网格结构的主要形式,广泛应用于公共建筑与工业建筑,尤其在设置悬挂吊车的工业厂房中占有垄断地位。悬挂吊车作用下网架结构的疲劳问题是工程界和学术界关注的热点。网架结构的疲劳主要是节点连接的疲劳。一方面,由于理论研究的不系统和疲劳试验数量不足,致使国家相关规范至今未对平板网架结构的疲劳设计方法做出明确规定。另一方面,因工程设计人员在进行网架疲劳设计或验算时,无据可依,阻碍了平板网架结构在工业厂房中的推广应用。本文以网架结构中常用的钢管-焊接空心球连接节点(下文简称管球连接节点)为研究对象,研究内容如下：(1)利用有限元分析软件,对管球连接节点模型进行理论计算分析,得出了轴向拉力作用下管球连接节点的应力分布规律；通过改变管球连接节点中空心球的D与T、钢管的d与t、焊缝w五个基本参数,经计算分析得到了应力集中系数的变化规律；并通过回归拟合得到了管球连接节点应力集中系数的数值解。(2)在有限元分析的基础上,通过管球连接节点的静力拉伸试验,采集了管球连接节点关键部位的应变,计算得到测点的应力,经回归拟合得到了管球连接节点实测应力分布曲线,计算得出应力集中系数,并与理论分析结果进行了对比分析。(3)利用AMSLER疲劳试验机,在自主设计的加载装置上,采用三种加载方式,分别对29个管球连接节点足尺试件进行了常幅、变幅疲劳试验,通过回归分析,得出了管球连接节点的S-N曲线。(4)利用放大镜与扫描电子显微镜分别对管球连接节点的疲劳断口进行了宏观和微观分析,揭示了管球连接节点的疲劳破坏机理。通过分析影响管球连接节点疲劳性能的因素,给出了提高疲劳强度的有效措施。(5)根据疲劳试验所得S-N曲线,确定了疲劳计算参数C、β及[△σ]等,并建立了以热点应力幅为基本参量的管球连接节点实用疲劳设计方法。本文研究工作主要创新点如下：·设计了一套管球节点疲劳试验加载装置,该装置可对空间网格结构连接节点进行疲劳试验,具有3种不同加载模式可供选择。·通过对疲劳破坏断口的宏观与微观分析,揭示了管球连接节点疲劳破坏机理。·提出了空间网格结构管球连接节点在轴心拉力作用下的热点应力集中系数的数值解。引入了“热点应力幅”的概念,建立了以热点应力幅为基本参量的空间网格结构管球连接节点的实用疲劳设计方法。本文的研究成果将成为我国钢管与焊接空心球节点疲劳相关设计规范的修订依据。其理论意义是在传统疲劳设计理论的基础上,定量地计算出热点应力；实用价值在于提供管球节点疲劳设计依据,解决工程问题,推动平板网架结构在工业建筑领域的大发展。更多还原

【Abstract】 As the paragon of space latticed structure, the plate space gird structure is widely used in the field of public and industrial constructions, especially in industrial buildings with hanging cranes. Currently, both engineering circle and academic community pay much attention to fatigue problem of space gird structure loaded by hanging cranes. The fatigue of joint connection is the main kind of fatigue of space gird structure. On the one hand, due to the lack of theory study and shortage of quality and quantity of fatigue test data, fatigue design methods of plate space gird structure has not been ruled officially. On the other hand, it is hard for designers to find proper proof when they have difficulties in space gird fatigue problems, which stops the application of plate space gird structure in the field of industrial buildings.Therefore, taking the steel tube-welded hollow spherical joint as research object (the tube-sphere joint, for short), this thesis goes as follow.(1) With the help of finite element analysis software, according to model of tube-sphere joint, the stress distribution law of tube-sphere joint loaded by axial tension was obtained. Besides, the change law of stress concentration factor was obtained by changing related parameters, such as D and T of hollow sphere, d and t of steel tube and w, A formula of stress concentration parameters of tube-sphere joint was proposed.(2) On the basis of finite element analysis, the stress of key parts of tube-sphere joint can be tested by static tensile test of tube-sphere joint, getting the measured stress distribution curve of tube-sphere joint, knowing the stress concentration parameters and do a comparison of testing results.(3) Respectively,29full-scale specimen of tube-sphere joint are used in both constant amplitude and variable amplitude tests, during which process, S-N curve of tube-sphere joint can be got by using AMSLER fatigue testing machine and three kinds of loading.(4) Use the Magnifying glass and the scanning electron microscope to analysis the fatigue fracture of tube-sphere joint macroscopically and microcosmically, revealing the fatigue mechanism of tube-sphere joint. In addition, proposed the effective solution to improve fatigue strength by analyzing related factors.(5) According to the fatigue curve from test, determine the fatigue calculative parameters C、β and [△σ], established the practical fatigue designing methods of tube-sphere joint, in which the hot spot stress amplitude is seen as the basic parameter. The creative points in this thesis lie in:Design a loading device used in space gird structure joint test on fatigue, which can be useful in steel tube-welded hollow spherical joint fatigue test, with3different loading methods to choose.Revealed the fatigue mechanism of tube-sphere joint by analyzing the fatigue fracture of tube-sphere joint macroscopically and microcosmically.Proposed a formula for stress concentration parameters of tube-sphere joint by static tensile. Established the practical fatigue designing methods of tube-sphere joint, in which the hot spot stress amplitude is seen as the basic parameter.The research achievement of this thesis will be the proof of reformulating related code on steel tube-welded hollow spherical joint design in our nation. In theory, it breaks the traditional design concept, proposed a formula for stress concentration parameters of tube-sphere joint. In practice, it also provides proof of designing and dealing with the problems in programs, promoting the development of plate space gird structure in the field of industrial construction.更多还原