摘要
冷弯型钢具有冷加工便捷、截面高效灵活、连接方便等优势,在冷弯型钢结构体系中得到广泛应用,同时疲劳破坏作为重要破坏形式之一,其研究对冷弯型钢的进一步推广具有重要意义。而新修订GB 50018—202X《冷弯型钢结构技术标准》(报批稿)中,尚无关于冷弯型钢抗疲劳设计的相关条文。为此,对0.8 mm和1.2 mm两种厚度、不同取材方向的LQ550冷轧高强薄钢板进行了拉伸高周疲劳试验,采用最小二乘法拟合得到反映疲劳性能的S-N曲线,并与现行相关规范和Q690高强钢已有疲劳试验曲线进行对比。试验结果表明:沿轧制方向取材的钢板疲劳性能优于垂直于轧制方向取材的钢板疲劳性能;厚度越大,沿轧制方向取材的钢板疲劳性能越差,垂直于轧制方向取材的钢板疲劳性能越好;两种厚度的钢板合并拟合且在95%保证率下,沿轧制方向的母材疲劳极限应力分别比AISC 360-2016、AISI S100-2016、GB 50017—2017的理论计算值提高192%、172%、165%,垂直于轧制方向的母材疲劳极限应力分别提高103%、88%、84%,即受轧制影响,钢板的疲劳性能远高于普通钢的;垂直于轧制方向取材的钢板疲劳性能和高强钢的相近。
Due to the advantages of convenient cold working,flexible section and easy connection,the application of cold-formed steel(CFS)structure system becomes more and more extensive.Meanwhile,as one of the important forms of damage,fatigue failure deserves investigation for further promotion of CFS.However,there are no relevant provisions on anti-fatigue design of CFS,even in the GB 50018—202X‘Standard for cold-formed steel structures’(revised version for approval).In this paper,tensile high-cycle fatigue tests were carried out on LQ550 cold-rolled high-strength steel sheets with thicknesses of 0.8 mm and 1.2 mm and with different rolling directions.The fitted S-N curves were compared with that predicted by the current design standards and previous Q690 high-strength steel fatigue tests.The results show that the fatigue performance of the steel sheet along the rolling direction is better than that cross the rolling direction.With increasing thickness,the fatigue performance of the steel sheet along the rolling direction is reduced,while that cross the rolling direction is increased.For steel sheets with thickness of 0.8 mm and 1.2 mm,with merged fitting and 95% survival probability,the fatigue limit stresses along rolling direction are 192%,172% and 165% higher than calculated values of AISC 360-2016,AISI S100-2016 and GB 50017—2017,respectively.The improvements of fatigue limit stress cross the rolling direction are 103%,88% and 84%,respectively.The results show that the fatigue performance of steel sheet is much higher than that of common steel due to the rolling effect.The fatigue performance of the steel sheet across the rolling direction is similar to that of high-strength steel.
作者
王雅倩
李元齐
WANG Yaqian;LI Yuanqi(College of Civil Engineering,Tongji University,Shanghai 200092,China)
出处
《建筑结构学报》
EI
CAS
CSCD
北大核心
2024年第4期189-197,共9页
Journal of Building Structures
基金
国家自然科学基金项目(51978500)。
关键词
LQ550冷轧高强薄钢板
高周疲劳性能
S-N曲线
轧制方向
钢板厚度
LQ550 cold-rolled high-strength steel sheet
high-cycle fatigue performance
S-N curve
rolling direction
thickness of steel sheet
