钢桁桥腹杆过焊孔处焊接细节疲劳性能研究

发布时间：2018-02-03 14:18

本文关键词： 钢桁桥疲劳实验热点应力法影响参数分析疲劳寿命　出处：《西南交通大学》2014年硕士论文　论文类型：学位论文

【摘要】：近年来,随着我国经济的飞速发展和交通的迫切需求,加上钢桁梁能应用于多种桥型之中,修建的钢桁桥也就越来越多。在重复的交变荷载作用下,钢桥疲劳问题越来越显著,己成为国内外学者研究的热点问题之一。钢桁桥作为大中跨钢桥采用的主要形式之一,但对一些焊接细节的疲劳问题研究还不够深入,因此在回顾了钢桁桥疲劳事故的基础上,采用热点应力法计算钢桁桥腹杆过焊孔处焊接细节的疲劳寿命。具体分为以下几个方面：1.对钢桥疲劳寿命评估理论与实验试件的几何尺寸设计进行介绍。通过疲劳实验得到带过焊孔的焊接细节及在过焊孔处填半圆弧板的焊接细节的疲劳寿命,对这两个焊接细节的疲劳性能进行对比分析。2.建立ANSYS有限元模型计算带过焊孔的焊接细节与在过焊孔处填半圆弧板的焊接细节的应力,然后建立有限元模型计算这两个焊接细节的焊址处的热点应力。采用热点应力法计算焊接细节的疲劳寿命,将热点应力法的疲劳寿命评估结果与实验结果进行比较。3.在计算带过焊孔的焊接细节焊址处的热点应力时,进行了影响热点应力的参数分析,主要是对焊址附近的有限元模型网格划分的精细程度、外推公式进行对比分析,得出了一些有益的结论。4.对焊接细节的应力集中系数的影响参数进行研究,对今后带过焊孔的焊接细节的设计与疲劳寿命的评估提供一定的参考价值。
[Abstract]:In recent years, with the rapid development of our economy and the urgent need of traffic, plus steel truss beam can be used in a variety of bridges, more and more steel truss bridges have been built under repeated alternating loads. The fatigue problem of steel bridge is becoming more and more obvious, and it has become one of the hot issues studied by domestic and foreign scholars. Steel truss bridge is one of the main forms of large and medium span steel bridge. However, the research on fatigue of some welding details is not enough, so the fatigue accident of steel truss bridge is reviewed. The fatigue life of steel truss bridge web rod welding details is calculated by hot spot stress method, which can be divided into the following aspects:. 1. The theory of fatigue life evaluation of steel bridge and the geometric design of experimental specimens are introduced. The welding details with overwelded holes and the fatigue life of semi-circular arc plates filled with over-welded holes are obtained through fatigue experiments. The fatigue properties of the two welding details are compared and analyzed. 2. The ANSYS finite element model is established to calculate the stress between the welding details with the overwelded holes and the welding details of the semi-circular arc plate filled in the over-welded holes. Then the finite element model is established to calculate the hot spot stress at the welding site of the two welding details, and the fatigue life of the welding detail is calculated by the hot spot stress method. The fatigue life evaluation results of the hot spot stress method are compared with the experimental results. 3. The parameters affecting the hot spot stress are analyzed in the calculation of the hot spot stress in the welding detail welding site with overwelded holes. It is mainly about the fine degree of mesh division of the finite element model near the welding site and the extrapolation formula. Some useful conclusions are drawn. 4. The influence parameters of stress concentration factor of welding detail are studied. It provides some reference value for the design of welding details and the evaluation of fatigue life with overwelded holes in the future.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U441.4

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