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Fracture research on Welded Beam-Column Connection under Cyclic Loading

循环荷载作用下焊接梁柱连接断裂研究

基本信息

批准号：
13650640
负责人：
MIMURA Hiroaki
金额：
$ 2.05万
依托单位：
Tokyo Denki University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2001
资助国家：
日本
起止时间：
2001 至 2002
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-13650640/
关键词：
steel structure welding beam-column connection crack propagation fracture mechanics

项目摘要

The fracture process composed of ductile crack initiation followed by stable crack growth and finally explosive failure in the welded beam-to-column connections we investigated experimentally.Tested specimens were T-type connections consisted of the perimeter column and beam. The column was a rectangular hollow section (□-250x250x9), and the beam was H-section (BH-300x150x6x12). The test parameters were 1) welded access hole-in or out of existence of scallop 2) controlled displacement amplitude-1.0△_p to 2.5△_p.The results of fracture test of welded beam-column connections under cyclic loading were as follows ;1. Fracture of specimens were the fell wide failure of beam flange by the crack propagation from (1) the groove weld between the diaphragm and the beam flange in non-scallop type, (2) the bottom of scallop when the displacement-amplitude was over 1.5△_p, in scallop type.2. The beam strength fell to 80% of full-plastic-moment of beam when the crack length grew up to 20% to 40% of flange width.3. In the crack propagation rate relation dN/da = C(△J)^m, test results were m = 1.15 to 1.44 for non-scallop type, and m = 1.34 to 1.61 for scallop type.4. The fatigue life of the non-scallop type were about two times of one of scallop type, so it made clear that non the scallop type was available structural detail under the disastrous earthquake motion.

试验研究了梁柱焊接连接由韧性裂纹萌生→稳定裂纹扩展→爆炸破坏的断裂过程。试验试件为由周长柱和梁组成的t型连接。柱为矩形空心截面（□-250x250x9），梁为h截面（BH-300x150x6x12）。试验参数为：(1)焊接孔内或不存在扇贝；(2)控制位移幅度为1.0△_p ~ 2.5△_p。循环荷载作用下焊接梁柱连接断裂试验结果如下：1。试件断裂为：(1)非扇贝型膜片与梁翼缘之间的坡口焊缝，(2)扇贝型位移幅值大于1.5△_p时的扇贝底部，裂纹扩展导致梁翼缘塌阔破坏。当裂缝长度增加到翼缘宽度的20% ~ 40%时，梁强度下降到梁全塑性弯矩的80%。在裂纹扩展速率关系dN/da = C（△J）^m中，非扇贝类型的裂纹扩展速率为m = 1.15 ~ 1.44，扇贝类型的裂纹扩展速率为m = 1.34 ~ 1.61。非扇贝式结构的疲劳寿命约为扇贝式结构的2倍，说明在灾难性地震作用下，非扇贝式结构是可行的结构细节。