销铰连接M36高强螺栓常幅疲劳性能试验  

Experiment on Constant Amplitude Fatigue of M36 High-strength Bolts in Pinned Connection

作　　者：焦晋峰[1] 李渊 刘勇[2] 郝海舒 邢颖 JIAO Jin-feng;LI Yuan;LIU Yong;HAO Hai-shu;XING Ying(College of Civil Engineering,Taiyuan University of Technology,Taiyuan 030024,China;Shandong Electric Power Engineering Consulting Institute Co.,Ltd.,Jinan 250013,China)

机构地区：[1]太原理工大学土木工程学院,太原030024 [2]山东电力工程咨询院有限公司,济南250013

出　　处：《科学技术与工程》2021年第9期3740-3746,共7页Science Technology and Engineering

基　　金：国家自然科学基金(51708384);山西省留学人员科技活动择优资助项目(DC1900000602);山西省基础研究青年基金(201901D211017)。

摘　　要：在循环荷载作用下,大跨度钢结构销铰连接高强螺栓可能发生疲劳失效。为研究其疲劳性能,针对材质35CrMoA的12.9级高强螺栓进行9组常幅疲劳试验,拟合得到应力-循环次数曲线(S-N曲线),数值模拟获得其应力分布规律及应力集中系数,并通过试件断口形貌揭示其疲劳破坏机理。结果表明:螺栓承压面第一节螺纹齿根及耳板对试件的挤压处应力集中较严重,理论应力集中系数为4.409;螺栓的疲劳破坏绝大部分起始于模拟所得试件的应力突变位置,断口疲劳破坏特征明显;所得S-N曲线可以反映不同应力幅下销铰连接高强螺栓的疲劳寿命,分别建立了以名义应力幅和缺口应力幅为变量的常幅疲劳计算公式;对比试验结果与《钢结构设计标准》(GB 50017—2017)规定的疲劳建议值,2×10~6次循环对应的名义应力幅与缺口应力幅分别为标准中构件类别Z11建议值的84.78%和373.8%,为构件类别J2建议值的42.39%和186.9%。Fatigue failure of high-strength bolts in pinned connection in large-span steel structure may occur due to cyclic loading.To study the fatigue property of the bolts,9 constant amplitude fatigue tests for the 12.9 grade M36 bolts with the material of 35CrMoA were carried out.The curve of stress vs number of cycle(S-N curve)was built by fitting.The stress distribution of the bolts and the stress concentration factor were obtained based on numerical simulation.The mechanism of fatigue failure was proposed by analyzing the graphs of high-strength bolt fatigue fracture.It was found that the stress concentration of the first thread root on the bearing surface and the point on the bolts where the connected plate crushed was serious,and the nominal stress concentration factor was 4.409.The destruction of most bolts started from the point of sudden change of stress from numerical simulation.The characteristics of fatigue failure of the bolt specimen fracture were obvious.Furthermore,the fatigue life of the specimens under different stress amplitudes could be reflected from the fitted S-N curves.The formulas for calculating the fatigue life under constant amplitude with nominal stress amplitude and notched stress amplitude as variables were obtained.By comparing the test results with the recommended values of allowable fatigue strength stipulated in China’s national standard for design of steel structures(GB 50017—2017),the corresponding nominal fatigue strength and notched fatigue strength at 2×106 times were 84.78%and 373.8%,of the recommended value of the standard for component Z11,and 42.39%and 186.9%for component J2,respectively.

关 键 词：销铰连接 高强螺栓 应力集中 疲劳试验 断口分析 

分 类 号：TU398.8[建筑科学—结构工程]