【作者】 王超；

【导师】 申红侠；

【作者基本信息】 西安建筑科技大学 ， 结构工程， 2020， 硕士

【摘要】 与普通钢材相比,高强钢构件的屈服强度更高,在工程建设领域合理采用高强钢能够减小构件的截面尺寸和自重,增大结构跨度和高度。然而,随着钢材屈服强度的提高,钢结构稳定的问题也更突出,高强钢结构可能在荷载尚未达到极限强度之前发生整体失稳或者局部失稳破坏。目前,国内外对高强钢局部稳定的研究主要集中在轴心受压构件和焊接工字形截面压弯构件,对于焊接箱形截面梁的研究相对较少。本文主要对高强钢焊接箱形截面受弯构件腹板的局部稳定性能进行研究,主要的研究内容和结论如下:(1)利用有限元软件ANSYS,建立考虑钢材强度等级、初始几何缺陷、残余应力、材料非线性的壳单元精细化有限元模型。本文详细阐述了有限元模型的建模过程和分析求解过程,对目前已有的相关试验试件进行数值模拟,通过有限元计算结果与文献中相关试验结果进行对比分析,验证了所采用有限元模型的科学性和有效性。(2)在此基础上,通过选择合理的构件参数,分析研究了翼缘宽厚比、腹板高厚比、钢材强度等级、钢材极限应变,钢材弹性模量、屈强比、残余应力和初始几何缺陷的变化对高强钢焊接箱形梁局部稳定性能的影响。(3)将有限元分析结果和国内外四部规范(中国《钢结构设计标准》GB50017-2017)、欧洲规范Eurocode 3、美国规范ANSI/AISC 360-16和日本规范(AIJ LSD 2010)进行对比,结果表明《钢结构设计标准》GB50017-2017和欧洲规范Eurocode 3的计算结果比较接近;前三部规范的截面分类均按照宽厚比小于限值划分板件等级,再根据板件的最大等级划分截面等级。日本规范则综合考虑了翼缘和腹板宽厚比对构件受弯性能的影响。在有限元分析的基础上,基于欧洲规范的四类截面分类标准,综合考虑焊接箱形梁的承载能力和转动变形能力,提出了适用于高强钢焊接箱形截面受弯构件同时考虑翼缘宽厚比和腹板高厚比的截面分类限值公式。(4)基于钢结构设计标准和有限元参数分析结果,进一步提出了纯弯荷载作用下考虑板件屈曲后强度的极限承载力的修正建议公式。将极限承载力的公式计算值与有限元模拟值进行对比,发现二者吻合良好。更多还原

【Abstract】 Compared with ordinary steel,the yield strength of high-strength steel components is higher,and the reasonable use of high-strength steel in engineering construction can reduce the cross-sectional size and self-weight of components and increase the span and height of the structure.However,as the yield strength of steel increases,the problem of steel structure stability becomes more prominent,and the high-strength steel structure may suffer from overall instability or local instability damage before the load reaches the ultimate strength.At present,domestic and international research on the local stability of high-strength steel is mainly focused on the axial compression members and welded Ibeam section bending members,and little research has been done on welded box-section beams.In this study,the local stability mechanical properties of the webs of welded boxsection bent members of high-strength steels were mainly studied,and the main research content and conclusions are as follows.(1)By using the general-purpose finite element software ANSYS to build a model,a fine-grained finite element model of the shell unit considering the strength level,initial geometric defects,residual stresses,and material nonlinearity of the steel was established.In this study,the modeling process and analytical solution process of the finite element model were described in detail,and numerical simulations were performed on the existing specimens,and the results of the finite element calculations were compared and analyzed with the relevant test results in the literature to verify the scientific validity and effectiveness of the adopted finite element model.(2)By selecting reasonable component parameters,the effects of changes in flange width-thickness ratio,web height-thickness ratio,steel strength grade,steel ultimate strain,steel elastic modulus,yield ratio,residual stress and initial geometric defects on the local stable force performance of welded box girder members were analyzed and studied.(3)The results of the finite element analysis were compared with four domestic and international codes(Chinese "Steel Structure Design Standard" GB50017-2017,European Code Eurocode 3,American Code ANSI/AISC 360-16,and Japanese Code AIJ LSD 2010).The results show that the calculation results of GB50017-2017 and Eurocode3 are close to each other;the cross-sectional classification of the first three codes are based on the classification of the slab class according to the width-to-thickness ratio less than the limit value,and then on the maximum class of the slab.The Japanese code takes into account the effect of the flange and web aspect ratio on the bending performance of the member.On the basis of finite element analysis,based on the four types of crosssectional classification criteria of the European code,and taking into account the load capacity and rotational deformation capacity of welded box girders,a limit value formula for the cross-sectional classification of welded box members of high-strength steel in bending,taking into account the flange width-to-thickness ratio and web height-tothickness ratio,was proposed.(4)Based on the steel structure design standards and finite element parameter analysis results,the proposed formula was further proposed to modify the ultimate load capacity after considering the flexural strength of the plate under pure bending load.The calculated values of the formula for the ultimate load were compared with the FEM simulation values,and it is found that the two agree well.更多还原