The Study on Improvement Method of Fatigue Strength of Steel Bridge Weld member

钢桥梁焊接构件疲劳强度提高方法的研究

基本信息

批准号：
05452233
负责人：
MIKI Chitoshi
金额：
$ 2.88万
依托单位：
Tokyo Institute of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (B)
财政年份：
1993
资助国家：
日本
起止时间：
1993 至 1994
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-05452233/
关键词：
Improvement Method of Fatigue Strength Weld Metal Undermatching Post-Teating Weld Defect Configuration of Weld toe Hardness Weld Residual Stress 溶接疲労強度軟質溶接 TIG処理化粧溶接溶接継手ブローホールき裂発生確率き裂進展解析

项目摘要

The improvement methods of fatigue strength of weld joints were studied at the following two view points, 1.the effects of weld metal, 2.the effects of post-treating of weld toe. In this study, longitudinal weld joints and longitudinal weld rib joints were investigated. Consequdntly, the following three main results were obtained.(1) Using longitudinal joints, the effects of undermatching of weld metals on fatigue strength of weld joints were investigated experimentally and statistically. The results showed that the undermatching makes the weld tensile residual stress at the weld joints, probability of weld defect occurrence, and probability of fatigue crack initiation from the weld defects decrease.(2) Using longitudinal weld rib joints, the effects of weld metal and post-treating of weld toe on fatigue strength of weld joints. The results showed that changes of weld metals and post-treating affected on the configuration of weld bead (including weld toe), hardness, and weld residual stresses. And choosing appropriate weld metals and post-treating of weld toe improved the fatigue strength of weld joints.(3) To evaluate the application of the above-mentioned two results (1) (2) to real steel bridge structure, fatigue tests with large girder specimens were performed. The large girder specimen had same wedl condition as small specimens which were used in (1) (2). The results showed that undermatching of weld metals and TIG-dressing improved the fatigue strength, and that the improvement method evaluated in this sutyd were effective on the real steel bridge structures.

在以下两个观察点：焊接金属的效果，2。焊接后处理后的效果。在这项研究中，研究了纵向焊接接头和纵向焊缝接头。因此，获得了以下三个主要结果。（1）使用纵向关节，通过实验和统计学上研究了焊接金属对焊接接头疲劳强度的影响。结果表明，不匹配使焊接接头处的焊缝拉伸残留应力，焊缝缺陷的发生概率以及焊缝缺陷疲劳裂纹启动的可能性减少。（2）使用纵向焊缝肋骨接头，焊接金属的效果和焊接后焊缝对疲劳性强度的焊接作用。结果表明，焊接金属的变化和对焊珠（包括焊缝），硬度和焊接残留应力的构型影响。（3）选择了适当的焊接金属和焊接后的焊接后进行治疗。（3）进行了上述两个结果（1）（2）在真实钢桥结构中的应用，进行了大型Girder样品的疲劳测试。大梁样品具有与（1）（2）中使用的小样本相同的WEDL条件。结果表明，焊接金属和tig涂层的不匹配改善了疲劳强度，并且在该缝隙中评估的改进方法对真实的钢桥结构有效。