FATIGUE OF LARGE-SIZED LONGITUDINAL BUTT WELDS WITH PARTIAL PENETRATION
FATIGUE OF LARGE-SIZED LONGITUDINAL BUTT WELDS WITH PARTIAL PENETRATION
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局部焊透大尺寸纵向对接焊缝的疲劳
DOI：
10.2208/jscej1969.1982.322_143
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发表时间：
1982
期刊：
影响因子：
4.2
通讯作者：
Hiroyuki Takenouchi
中科院分区：
文献类型：
--
作者：
C. Miki;J. Tajima;K. Asahi;Hiroyuki Takenouchi
本州-四国大桥的神户-火影忍者和小岛-Sakaide线路被设计为铁路和公路相结合的类型。因此，活载引起的疲劳将是一个严重的问题。本州-四国大桥设计中采用的许用疲劳应力是根据文献[1]中各种接头试件的试验结果确定的。然而，在以往的疲劳试验中，由于试验机能力的限制，试件的形状和尺寸受到了相当大的限制，考虑到桥梁的规模，有必要使用更大的试件来检查各种节点的疲劳性能。因此，本州-四国大桥管理局已经制造了一台最大动载能力为400吨[4×106N]的疲劳试验机，目前正在对结构的接头和部件进行疲劳试验。采用厚度为45 mm的800-N/mm~2级高强度钢试件，对部分穿透纵焊构件的疲劳性能进行了试验研究。本州-四国大桥一般使用45毫米厚的板材。对于日本的铁路桥1)这种类型的接头的允许疲劳应力是A类最高强度组的：在脉动应力下的15.3公斤/平方毫米(150牛顿/平方毫米)。本州-四国大桥2也考虑采用同样的价值。然而，在3&4节点板式桁架结构的疲劳试验中，仅在少量重复应力不超过上述许用应力的情况下，在箱形截面桁架构件的角焊缝处就产生了疲劳裂纹。因此，对于本州-四国大桥，这种接头今天被归类为B类(12.75公斤/平方毫米(125牛顿/平方毫米)在脉动应力下)5)。作者等人之前的疲劳研究。艾尔在普通尺寸的单斜面坡口焊缝试件上，已经阐明了由于焊接残余应力的存在而导致的疲劳强度降低是非常显著的。伊藤等人、S等人对同类型节点的研究表明，这种节点的疲劳强度随着试件尺寸的增大而降低，因此，用小尺寸试件来证实这种节点的疲劳性能对于防止钢构件的疲劳破坏是很重要的。
The Kobe-Naruto and Kojima-Sakaide routes of the Honshu-Shikoku bridges are designed to be of the combination railway and highway type. Consequently, fatigue due to live loads will pose a problem of grave importance. The allowable fatigue stresses employed in the designs of Honshu-Shikoku bridges have been determined on the basis of results of tests on various joint specimens as indicated in [1]. However, the configurations and dimensions of specimens in fatigue tests performed in the past were fairly restricted due to limitations in the capacities of testing machines, and considering the scales of the bridges, it is necessary to examine fatigue properties of various joints using larger specimens. Accordingly, the Honshu-Shikoku Bridge Authority has had a fatigue testing machine of the capacity of maximum dynamic load of 400 ton [4 x 106 N] made and is now carrying out fatigue tests of joints and parts of structures. In the present study, fatigue properties of the partially penetrated longitudinal welded members were examined experimentally using specimens of 800-N/mm2 class high tensile strength steel 45 mm in thickness. Plates 45-mm thick will generally be used in Honshu-Shikoku bridges. For railway bridges in Japan1) the allowable fatigue stress for this type of joint is that for the highest strength group, Category A: 15.3 kg/ mm2 (150 N/mm2) under pulsating stress. Adoption of the same value had been considered for the Honshu-Shikoku bridges2. However, in fatigue tests of panel point structures of trusses3>>4, fatigue cracks were initiated at corner welds of box section truss members after only a small number of repetitive stresses which were not more than the above-mentioned allowable stress. Consequently, for the Honshu-Shikoku bridges, this joint is classified today as Category B (12.75 kg/mm2 (125 N/mm2) under pulsating stress)5). Previous fatigue studies by the authors et. al. on common-size single-bevel groove weld specimens have clarified that the reduction in fatigue strength due to existence of welding residual stress is very substantial6>>'> and that fatigue cracks are initiated from bottom surfaces of weld metal at extremely early stages of the lives'. Studies by Ito et al.'s on the same kind of joint suggested that fatigue strength of this joint decreases as the size of the specimen is enlarged, and therefore, it is important for prevention of fatigue failure of steel members that the fatigue properties of this joint indicated by small-size specimens be confirmed with large specimens.