基于弯矩分配的受拉T型连接高强螺栓受力性能

发布时间：2018-08-11 13:13

【摘要】：T型连接件是常用的被等效简化的梁柱高强螺栓连接单元。几十年来,国内外学者通过大量的试验与研究,建立了高强螺栓T型连接受力的基本理论,深入探讨了撬力对节点破坏模式的影响。撬力的作用使得螺栓内力增大,降低了螺栓承载力,使T型件螺栓处翼缘板产生了弯矩。中美欧各国都有考虑撬力的螺栓连接设计规范,但都将螺栓假定为轴心受拉构件,并未考虑弯矩的计算。本文以螺栓受拉弯作用发生屈服为出发点,通过试验与有限元软件模拟分析的方法,对T型连接高强螺栓受拉性能进行深入研究。本文以高强螺栓T型连接件为对象,变化螺栓直径、螺杆长度、预紧力大小、翼缘板板厚、内翼缘板板长与外翼缘板板长6个参数,设计了7个试样,通过拉伸试验探讨各变量对螺栓内力的影响。研究表明弯曲应力随着荷载增大而增大,屈服时弯曲应力占总应力比值可超过40%。改变尺寸参数可改变破坏模式和承载力,增大板厚和螺栓直径可以提高承载力;增大内翼缘板板长会提高撬力值,降低螺栓承载力;改变螺栓杆长和外翼缘板板长对螺栓承载力影响不大。使用ANSYS软件扩大参数对22个T型连接件建立了等尺寸实体模型进行有限元分析,分析结果表明:撬力(T型件与底件间的接触轴力)以分布力的形式在各试样中是普遍存在的,其合力作用点随着外荷载的增大逐渐偏向外侧远离螺栓中心;螺栓受到弯矩的作用,处于拉弯状态;接触轴力的力臂和螺栓所受的弯矩与外荷载、螺栓直径、翼缘板厚度、内翼缘板长度、外翼缘板长度,螺杆长度都有关系。本文提出了新的T型件受力模型,通过计算接触力臂,弯矩分配比值等参数,提出了螺栓轴力与弯矩的计算方法。结果表明:各参数的拟合计算式所计算的结果与有限元模拟结果吻合程度较好,并选择算例进行验证,其结果是偏于安全且适用的。
[Abstract]:T-type connectors are commonly used as equivalent simplified Liang Zhu high-strength bolt connection units. In recent decades, through a lot of experiments and researches, scholars at home and abroad have established the basic theory of the stress of high-strength bolt T-joint, and deeply discussed the influence of pry force on the failure mode of joints. The action of prying force increases the internal force of the bolt, reduces the bearing capacity of the bolt, and results in the bending moment of flange plate at the bolt of T-shaped part. The design code of bolt connection considering prying force is used in both China and Europe, but the bolt is assumed to be an axial tensile member, without considering the calculation of bending moment. In this paper, the tensile properties of T-joint high-strength bolts are studied by means of test and finite element software simulation analysis, based on the tensile and bending yield of bolts subjected to tension and bending. In this paper, the high strength bolt T-joint is taken as the object. Seven specimens are designed, including the diameter of the bolt, the length of the screw, the preload force, the thickness of the flange plate, the length of the inner flange plate and the outer flange plate, and the length of the inner flange plate and the outer flange plate. The effect of various variables on the internal force of bolts was investigated by tensile test. The results show that the bending stress increases with the increase of load, and the ratio of bending stress to total stress at yield can exceed 40%. The failure mode and bearing capacity can be changed by changing the dimension parameter, the bearing capacity can be increased by increasing the thickness of plate and the diameter of bolt, and by increasing the plate length of inner flange plate, the value of prying force will be increased and the bearing capacity of bolt will be reduced. The change of bolt length and outer flange plate length has little effect on bolt bearing capacity. The finite element analysis of 22 T-type connectors is carried out by using the expanded parameters of ANSYS software. The results show that the prying force (the contact axial force between the T-shaped part and the substrate) is widely used in each specimen in the form of distributed force. With the increase of the external load, the acting point of the joint force gradually deviates from the center of the bolt; the bolt is under the action of bending moment and is in the state of tension and bending; the arm and bolt of contact axial force are subjected to bending moment and external load, the diameter of bolt, the thickness of flange plate, the diameter of bolt, the thickness of flange plate, The length of the inner flange plate, the outer flange plate and the screw length are all related. In this paper, a new stress model of T-shaped parts is presented. The calculation method of axial force and bending moment of bolt is put forward by calculating the parameters of contact arm and moment distribution ratio. The results show that the calculated results are in good agreement with the results of finite element simulation, and the results are relatively safe and applicable.
【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU391

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