Study on the Lateral-Torsional Buckling of Duplex Stainless Steel Welded I-Section Flexural Members
-
摘要: 不锈钢结构具有良好的力学性能和优异的耐腐蚀性,是强腐蚀性环境下重要基础设施的最佳结构方案之一。关于不锈钢结构的研究始于20世纪60年代,随着人们对结构耐久性和安全性重视程度的不断提升,相关研究在近20年得到迅猛发展。现有研究在不锈钢材料力学性能和冷成型构件的设计理论方面积累了丰富的成果,然而在焊接截面构件的受力性能方面研究相对较少,且尚未将不锈钢材料力学特征融合到构件设计方法中。为此将对焊接双相型不锈钢工字形受弯构件整体稳定性能进行试验研究,结合双相型不锈钢材料的力学特征,改进相应的设计公式。
首先设计了一种加载点约束型钢梁整体稳定试验的四点受弯装置,摒弃传统试验装置释放加载点约束的策略,采用加载点约束型,实现加载与侧向约束同点布置,明确构件的边界条件,有效降低装置对构件的多余约束;然后针对7根受弯构件开展了初始缺陷测量、材料力学性能试验和整体稳定性能试验,获得了全面的试验数据,并将试验数据与欧洲规范和中国规范的预测值进行了对比;建立了受弯构件的有限元分析模型,将有限元分析结果与试验结果进行对比验证模型的准确性,并采用该模型进行了参数化分析;最后基于参数化分析结果,考虑不锈钢材料的屈服后显著应变强化的特点,改进了钢梁整体稳定承载力计算公式。
试验中除S-DI-150-3000发生局部-整体相关屈曲外,其余构件均发生侧向弯扭屈曲破坏,将试验结果与欧洲规范和中国规范预测值进行对比,结果表明:上述规范的预测值均偏于保守,试验值与计算值比值的均值分别为1.23和1.18;所建立的有限元分析模型可以准确预测构件的承载力,试验值与计算值比值的均值为1.06;基于参数化分析结果和不锈钢材料的特点,建立了两阶段的受弯构件整体稳定承载力的计算公式,当正则化长细比不小于0.54时,采用改进的Perry公式表达正则化长细比与稳定系数之间的关系;当正则化长细比小于0.54时,近似采用线性方程表达两者的关系;在此阶段构件稳定系数大于1.0,以抗拉强度与屈服强度的比值作为最大值,充分利用不锈钢材料屈服后显著应变强化的特征。将试验数据与所提公式的计算值进行对比表明:该方法具有较高的精度,试验值与所提公式预测值的比值均值为1.0,标准差为0.11。Abstract: Stainless steel structure has good mechanical properties and excellent corrosion resistances, which is one of the best choices of the structural schemes for important infrastructures in highly corrosive environments. Related researches on stainless steel structures began from 1960s, and have grew rapidly in the past 20 years as the more and more attentions have been taken to the durability and the safety of structures. Currently, researches on stainless steel structures mainly focused on the material properties and the performance of cold-formed members, while the researches on the behavior of the stainless steel welded members were rare. Besides, the material characteristic of stainless steel has not been fully incorporated into the design method. This study would report an experimental study on the lateral-torsional buckling of duplex stainless steel welded I-section flexural members, and modify the related design formula to include the material properties characteristic of duplex stainless steel.
Firstly, a four-point bending test rig with the strong constraints at the loading points was proposed for the lateral-torsional buckling test in this study. In this test rig, to clarify the boundary conditions and reduce the possible redundant constraints from the test rig applied to the test specimen, the lateral constraints were configured at the same location as that of the loading points, which was different from the traditional test rig that following the concept to release the constraints at the loading points. A series tests were then conducted for seven flexural members to obtained full set of test data, including the initial geometric imperfection, the material properties, and the failure mode and capacity. The test data was compared with the predictions of Eurocode and Chinese code. Finite element models of the welded stainless steel flexural members were established and verified by test data, and then parametric analysis were carried out. Based on the results of parametric analysis, the design formulas for the lateral-torsional buckling were modified considering the strain hardening characteristic of stainless steel.
All the specimens showed the lateral-torsional buckling except the S-DI-150-3000, which had the local-global interaction buckling. Comparisons between the test data and the predicted values of the Eurocode and the Chinese code showed that the predicted values of the two design codes were both conservative. The mean ratios of the test values over the predicted values were 1. 23 and 1. 18, respectively. The finite element model can accurately predict the bearing capacity. The mean ratio of the test values over the bearing capacity obtained by finite element analysis was 1. 06. Based on the analysis results and the characteristic of stainless steel, a two-stage formula was established. When the slenderness was not less than 0. 54, the modified Perry formula was used to express the relationship between the slenderness and the reduction factor. When the slenderness was less than 0. 54, a linear relationship between the slenderness and the reduction factor was approximately employed. To make full use of the characteristic of considering strain hardening after yielding, the reduction factor was allowed to be greater than 1. 0 with the maximum value of the ratio of the tensile stress over the nominal yield stress. Comparisons of the test data and the predictions of the proposed formulas showed that the proposed formula can accurately predict the bearing capacity. The mean ratio of the test values over the predicted values was 1. 00, with a low scatter of 0. 11.-
Key words:
- duplex stainless steel /
- welded I-sections /
- flexural members /
- tests /
- finite element analysis /
- Perry formula
-
Bredenkamp P J, Van Den Berg G J. The lateral torsional buckling strength of cold-formed stainless steel beams[C]//Twelfth International Specialty Conference on Cold-Formed Steel Structures:Recent Research and Developments in Cold-Formed Steel Design and Construction. Rolla, MO:University of Missouri-Rolla, 1994:539-549. Bredenkamp P J, Barnard H. The lateral torsional buckling strength of hot-rolled stainless steel beams[J]. The Structural Engineer, 1996, 74(19):316-319. Burgan B A, Baddoo N, Gilsenan K A. Structural design of stainless steel members-comparison between Eurocode 3, part 1.4 and test results[J]. Journal of Constructional Steel Research, 2000, 54:51-73. Stagenberg H. Structural design of stainless steel welded I-beams, I-columns, and beam-columns[R]. Germany:European Coal and Steel Community, 2000. Niu S, Rasmussen K J R, Fan F. Local-global interaction buckling of stainless steel I-beams. I:experimental investigation[J]. Journal of Structural Engineering, 2014,141(8).DOI: 10.1061/(ASCE)ST.1943-541X.0001137. Niu S, Rasmussen K J R, Fan F. Local-global interaction buckling of stainless steel I-beams. II:numerical study and design[J]. Journal of Structural Engineering, 2014.DOI: 10.1061/(ASCE)ST.1943-541X.0001131. 王元清, 高博, 戴国欣,等. 焊接不锈钢工字形截面梁整体稳定性试验研究[J]. 建筑结构学报,2011, 32(11):143-148. 王元清, 高博, 戴国欣,等. 焊接工字形截面不锈钢受弯构件的整体稳定性分析[J]. 沈阳建筑大学学报(自然科学版), 2010, 26(6):1021-1026. 中华人民共和国建设部. 钢结构设计规范:GB 50017-2003[S]. 北京:中国计划出版社, 2003. 沈晓明. 不锈钢受弯构件及构件中的受压板件(组)的理论分析和试验研究[D]. 南京:东南大学, 2011. 舒赣平, 辛连春, 郑宝锋,等. 不锈钢焊接工字形截面梁整体稳定性分析[J]. 工业建筑, 2015,45(12):23-31. Zheng B F, Shu G P, Xie F Z, et al. Design of cold-rolled stainless steel rectangular hollow section columns[J]. Journal of Constructional Steel Research, 2020, 170.DOI: 10.1016/j.jcsr-2020.106072. The Steel Construction Institute.Design manual for structural stainless steel[S].4th ed. UK:The Steel Construction Institute, 2017. 中华人民共和国住房和城乡建设部.钢结构施工质量验收标准:GB 50205-2020[S]. 北京:中国计划出版社,2020. 全国钢标准化技术委员会. 金属材料拉伸试验第1部分:室温试验方法:GB/T 228.1-2010[S]. 北京:中国标准出版社, 2010. Gardner L, Nethercot D A. Experiments on stainless steel hollow section-part1:material and cross-sectional behavior[J]. Journal of Constructional Steel Research, 2004, 60(9):1291-1318. Rasmussen K J R. Full range of stress-strain curves for stainless steel alloys[J]. Journal of Constructional Steel Research, 2003, 59(1):47-61. ECS. Eurocode 3:design of steel structures-part 1.4:general rules-supplementary rules for stainless steels:EN 1993-1-4[S]. Brussels:European Committee for Standardization,2006. 中国工程建设标准化协会.不锈钢结构技术规程:CECS 410:2015[S].北京:中国计划出版社,2015. Yuan H X, Wang Y Q, Shi Y J, et al. Residual stress distributions in welded stainless steel sections[J]. Thin-Walled Structures,2014,79:38-51. 全国钢标准化技术委员会.焊接H型钢:YB 33814-2017[S]. 北京:中国标准出版社, 2017. 全国钢标准化技术委员会.热轧H型钢和剖分T型钢:GB/T 11263-2017[S]. 北京:中国标准出版社,2017. Rasmussen K J R, Rondal J. Strength curves for metal columns[J]. Journal of Structural Engineering, 1997,123:721-728.
点击查看大图
计量
- 文章访问数: 433
- HTML全文浏览量: 124
- PDF下载量: 31
- 被引次数: 0