【作者】 李晶；

【导师】 赵金友；

【作者基本信息】 东北林业大学 ， Structural Engineering， 2020， 硕士

【摘要】 随着工业水平的进步,钢材生产工艺逐步提高,高强度钢材(屈服强度大于或等于460MPa)已广泛应用于大跨度高层建筑结构中。高强度钢材在材料性能、生产加工工艺等方面较普通强度钢材存在明显差异,整体稳定性能也不尽相同。然而,国内外现行钢结构设计规范中的相关设计方法均是基于普通强度钢构件的研究结果制定,而对于高强度钢材钢构件,缺乏较为成熟的设计方法。本文采用试验与有限元分析的方法对Q460高强钢简支梁的整体稳定性能展开详细研究,主要研究内容和成果如下:采用截面法对3种Q460高强钢焊接工字形截面的残余应力进行了测量,得到了双轴对称、上翼缘加强和下翼缘加强工字形截面的残余应力分布规律,建立了三种截面下的残余应力分布模型,为后续有限元建模与参数化分析提供了重要依据。进行了 10个Q460高强钢焊接工字形截面简支梁的整体稳定性能试验,试验结果表明,10根试件均发生了整体弯扭屈曲的破坏模态;上翼缘加强型工字形截面梁的整体稳定极限承载力明显高于下翼缘加强型的,并高于双轴对称型的,加强翼缘宽度可明显提高钢梁的整体稳定极限承载力。采用ANSYS有限元程序对试件进行了模拟,有限元分析所得试件的失稳破坏模态、整体稳定极限承载力和跨中荷载-位移曲线与试验结果较为吻合,验证了有限元模型的准确性。并开展了大量Q460高强钢焊接工字形截面简支梁整体稳定性能的有限元参数分析,得到了构件基于不同截面形式、跨度等影响参数的整体稳定极限承载力。将试验结果及有限元参数分析结果与各国规范中受弯构件整体稳定性能的相关计算值进行了对比,结果表明采用我国钢结构设计规范(GB50017-2017)和美国钢结构规范(ANSI/AISC360-2016)计算该类构件较不安全,欧洲钢结构规范(Eurocode3-2005)的计算结果较为保守,我国高强钢结构设计规程(征求意见稿)(JGJX-201X)的计算结果最为接近且安全。基于JGJX-201X中受弯构件整体稳定极限承载力计算公式,对相关系数进行了修正,重新拟合了整体稳定承载力计算曲线,提出了适用于Q460高强钢焊接工字形截面梁整体稳定承载力的设计方法。更多还原

【Abstract】 With the gradual improvement of produaction technology of steel,high strength steel which yield strength greater than or equal to 460MPa is widely used in domestic and foreign building structures.High strength steel in material mechanics performance,influencing of the production process,as well as the initial defects has obvious difference with ordinary strength steel,the overall stability performance are also different.However,the design formulas of steel components concerned in the current design specifications in domestic and foreign are formulated based on the test and theoretical research of Q235 and Q345 ordinary strength steel components,and there is a lack of mature calculation theory and design method for the mechanical properties of high strength steel components.In this paper,the overall stability of simply supported beam of Q460 high strength steel is studied by the method of finite element analysis and experimental research.The basic contents and results of research are as follows:Three types of welded I-section of Q460 high strength steel residual stresses were measured by cross section method,,and the distribution law of residual stresses of double-axial symmetry,upper flange strengthening and lower flange strengthening I-section was obtained.The overall stability of 10 welded I-section simply supported beams of Q460 high strength steel was tested.Top flange is significantly higher than the overall stability of bearing capacity for reinforced I-section beam bottom flange reinforced,enhanced overall stability bearing capacity of single axisymmetric I-section beam above the biaxial symmetry model,to strengthen the flange width can obviously improve the integral stability bearing capacity of steel beams.ANSYS finite element program was used to simulate the test.The instability failure mode,overall stability bearing capacity and mid-span load-displacement curve of the specimens obtained by finite element analysis were in good agreement with the test results,which verified the accuracy and reliability of the finite element model.On this basis,a large number of finite element parameter analysis on the overall stability of simply supported beams of welded I-section of Q460 high strength steel was carried out by transforming the section aspect ratio and regularized length-thin ratio of members,and the overall stability bearing capacity of members was obtained based on the influence parameters.Compared the test with finite element calculation results and the national standard,the results show that the steel structure design codes in China(GB50017-2017)and American standard(ANSI/AISC360-2016)to calculate the overall stability bearing capacity of high strength steel welded I-section beam Q460 is unsafe,European specification(Eurocode3-2005)of the calculation results are more conservative,high strength steel structure desion codes in China(draft)(JGJX-201X)the calculation result is the closest and is safe.Based on the calculation formula of the overall stability bearing capacity of the bending member in JGJX-201X,the calculation curve of the overall stability bearing capacity was fitted again,and a design method for the overall stability bearing capacity of the welded I-section beam of Q460 high strength steel was proposed.更多还原