【作者】 廖芳芳；

【导师】 何保康；

【作者基本信息】 西安建筑科技大学 ， 结构工程， 2007， 硕士

【摘要】 本文对550MPa高强冷弯薄壁型钢帽型截面27根简支檩条和27根搭接式两跨连续檩条试件的弯曲性能进行了试验研究。试件分TOPSPAN 40和TOPSPAN 61两种截面形式，TOPSPAN 40试件按截面板件厚度t=0.48mm、0.6mm分为两组，每组试件跨度分别取L=1200mm、1800mm、2400mm；TOPSPAN 61试件按截面板件厚度t=0.75mm、1.00mm分为两组，每组试件跨度分别取L=1800mm、2400mm、3000mm。试验结果表明：按我国现行规范《冷弯薄壁型钢结构技术规范》GB50018-2002计算550MPa高强冷弯薄壁型钢受弯檩条的极限承载力将偏于不安全。在试验结果的基础上，本文采用大型有限元程序ANSYS9.0对高强冷弯薄壁型钢受弯构件进行了几何、材料和接触非线性数值模拟分析，所得的有限元计算结果与试验结果吻合较好。同时还利用ANSYS进行了一些参数分析，分析了截面板件厚度对简支檩条极限承载力的影响，分析了搭接长度和搭接构造对搭接式两跨连续檩条的影响。对搭接式两跨连续檩条搭接段自攻螺钉的接触非线性问题，提出了耦合线位移的建议分析方法，从分析结果可以看出这种方法是比较理想的。考虑到高强钢材的材料特性，本文采用折减屈服强度的方法来计算受弯构件的极限承载力。通过有效宽度法和直接强度法计算简支檩条的结果与试验结果的对比，建议截面板件厚度t=0.48mm、0.6mm和0.75mm的试件强度折减系数γ取0.80，t=1.00mm的试件折减系数γ取0.90。搭接式两跨连续檩条在各组试件强度折减系数γ取定的基础上，根据试验结果可得试件TS40-0.48、TS40-0.60搭接段刚度系数β取1.2，试件TS61-0.75和TS61-1.00β取1.5，用我国规范GB50018-2002规定的有效宽度法计算结果与试验值比较吻合。更多还原

【Abstract】 The bearing capacity behavior of 550MPa high strength cold-formed steel hat section 27 simply supported purlins and 27 lapped continuous purlins under bending has been studied in this paper. All the specimens are classified into TOPSPAN 40 and TOPSPAN 61. According to section thickness t=0.48mm or 0.6mm, specimens TOPSPAN 40 are divided into two groups, whose spans are Z,=1200mm 1800mm 2400mm separately, while according to section thickness t=0.75mm or 1.00mm, specimens TOPSPAN 61 are divided into two groups, whose spans are L=1800mm 2400mm 3000mm separately. The test results show that it is unsafe to calculate the ultimate bending bearing capacity of 550MPa high strength cold-formed steel purlins according to the current Chinese specification GB50018-2002.Based on the test results, the finite element program ANSYS 9.0 is applied to carry out the nonlinear finite element analysis of 550MPa high strength cold-formed steel purlins under bending. The results of the finite element method are much close to the test results. This paper also includes some parameter analysis by using ANSYS, such as the effect of section thickness to the ultimate bearing capacity of simply supported purlins, the effect of overlapping length and constructional detail to lapped continuous purlins. Meanwhile, the method of coupling linear displacement is proposed to substitute for touching effect in the self-drilling screws in the overlapping part of lapped continuous purlins. The results of analysis show that it is ideal to use this method.Considering the material characteristics of high strength steel, the method of reducing yield strength is applied to calculate the ultimate bearing capacity of purlins under bending. Comparing the calculated results of simply supported purlins by effective width method and direct strength method with the test results, this paper suggests that the strength reduction coefficient γ of specimens with section thickness t=0.48mm 0.6mm and 0.75mm be 0.80, while coefficient γ of specimens with section thickness t=1.00mm be 0.90. According to the determined strength reduction coefficient γ and test results, the stiffness coefficient β of overlapping part of lapped continuous specimens TS40-0.48 and TS40-0.60 is proposed to be 1.2, while the stiffness coefficient β of specimens TS61-0.75 and TS61-1.00 be 1.5. Then the calculated results by using effective width method specified by GB50018-2002 are close to the test results.更多还原