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Stress Distribution and Fatigue Strength of Welded Intersection between Steel Bridge Components under multi-axial Stresses

多轴应力下钢桥构件焊接相口的应力分布及疲劳强度

基本信息

批准号：
15560410
负责人：
MORI Takeshi
金额：
$ 2.3万
依托单位：
Hosei University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2004
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-15560410/
关键词：
intersection between main girder and lateral girder bi-axial stress directional variation of principle stress fatigue strength evaluation 3-dimensional FEM analysis bi-axial fatigue testing system 疲労強度部材交差部疲労照査 2軸疲労試験システム応力集中

项目摘要

The fatigue strength of the steel bridge component is specified on the basis of the fatigue test results under single-axial condition using model specimens for actual welded joints. However, in intersection between the main girder web and lateral girder flange, of I section plate girder bridges in which many fatigue crack experiences have been reported, bi-axial stresses occurs because the lateral girder flange stress acts by the load distribution action in addition to the main girder web stress resulting from bending of a main girder. Furthermore, in a main girder web, the direction of shear stress is reversed and the direction of the principle stress changes due to movement of load. This study is aiming at establishing fatigue strength evaluation method of the intersection between the main girder and lateral girder flange in consideration of bi-axial stress condition and the variation of principle stress.The items performed in this research and those contents are as follows.1.Stress … More analyses on 2 lane I section composite girder highway bridge of 30m in span (main-girder number 4) was conducted, and the stress properties at the intersection part was clarified.2.bi-axial fatigue testing system was developed.3.The results of fatigue test results using the bi-axial fatigue testing system were indicated for the purpose of considering the influence of two axial load on the fatigue strength of a main girder web weld.4.The results of fatigue tests and FEM stress analysis were indicated in order to make clear of the influences of the difference in the joint form by modeling of the weld joint part on fatigue strength of lateral girder flange weld to the main girder web.5.The results of examinations were shown on the influence of bi-axial load on the fatigue strength of a lateral girder beam flange weld.6.The results of bi-axial fatigue tests were indicated in order to clarify influence of the direction change of the principle stress on the fatigue strength of a main girder web weld. Then it was concluded that the influence of change of the direction of the principle stress can be evaluated by the difference of the maximum principle stress and the minimum stress in a direction of maximum one at the crack originating point.7.The fatigue strength evaluation method for the intersection between the main girder web and the lateral girder flange were proposed, and the example of fatigue examination was shown using the proposed method. Less

钢桥构件的疲劳强度是根据实际焊接接头的模型试件在单轴条件下的疲劳试验结果确定的。然而，在I形截面板梁桥的主梁腹板和横向梁翼缘之间的交叉处，其中已经报道了许多疲劳裂纹经验，由于横向梁翼缘应力除了由主梁弯曲引起的主梁腹板应力之外还通过载荷分布作用而作用，因此出现双向应力。此外，在主梁腹板中，由于荷载的移动，剪应力的方向相反，主应力的方向改变。本文旨在建立考虑双向应力状态和主应力变化的主梁与侧梁翼缘相交处疲劳强度评估方法，主要研究内容如下：1.应力 ...更多信息 30m跨2车道I型组合梁桥分析（主梁编号4）进行了，2.研制了双轴疲劳试验系统。3.对双轴疲劳试验结果进行了分析。为了考虑两个轴向载荷对主梁疲劳强度的影响，设计了一套轴向疲劳试验系统4.通过对焊接接头部位进行模拟，给出了疲劳试验和有限元应力分析结果，以明确接头形式的不同对主梁腹板与侧梁翼缘焊缝疲劳强度的影响。6.为了阐明主应力方向变化对主梁腹板焊缝疲劳强度的影响，给出了双轴疲劳试验结果。提出了主应力方向变化的影响可以通过裂纹起始点处最大主应力方向上的最大主应力与最小主应力之差来评价。7.提出了主梁腹板与侧梁翼缘相交处的疲劳强度评估方法。并给出了应用该方法进行疲劳检测的实例。少