冷弯薄壁C型构件屈曲滞回机理与简化设计方法研究
发布时间：2018-08-26 21:45
【摘要】：随着城市与新农村建设不断向前推进,尤其是国家权威部门已明确指出,新一轮GDP增长主要来源于农村的城镇化。建筑业作为城镇化的主要行业,其结构的形式与构造也须不断地改进和完善以适应建筑产业化的发展。其中,冷弯薄壁型钢结构体系作为工业化轻钢结构的一个分支倍受瞩目,其最显著的优势是施工周期短,可以提高投资效益,加快资金周转；并且施工场地占用率、建筑垃圾、建筑施工噪音等都大大降低。同时,轻钢结构建筑所用材料主要是可回收或易降解的材料,既节能、环保,又不失美观、大方,符合现代建筑发展方向理念。目前,冷弯薄壁型钢已广泛地应用于低层民用建筑中。其优点在于质轻,并且随着制造工艺的进步,屈服强度越来越高,耐久性也越来越好。同时,冷弯薄壁型钢的施工便捷性也是其它传统钢结构无法相比的,这些特点使得冷弯薄壁型钢在钢结构住宅产业化与新农村建设的大背景下,有着巨大的优势和发展前景。 本文选择应用最广泛、产业化程度最高的冷弯薄壁型钢C型构件作为研究对象,认为现有研究对相关屈曲机理、滞回性能以及适合各类截面的设计方法还存在一些值得深入的研究点。基于此,本文对以下内容展开了深入研究： (1)借鉴Shanley模型,推导了一维杆件屈曲的全过程,深入分析了一维杆件屈曲机理与影响因素,包括初始缺陷与截面参数等。在此基础上,根据塑性区域分布不同,将塑性分为理想塑性与分布塑性,并推导了一维杆件塑性分布区域的表达式,得到了影响塑性分布区域的影响因子。同时,基于杆件屈曲模型,分析了r(塑性刚度或屈曲后刚度)与杆件屈曲、塑性行为之间的关系,为后文薄壁构件屈曲机理分析作准备。 (2)对冷弯薄壁C型构件进行了试验研究与数值模拟,包括：水平循环荷载作用下的构件滞回性能、静轴力下的屈曲行为与破坏特点,以及静力和循环荷载作用下的构件组合作用。分别得到了冷弯薄壁型钢C型构件在循环荷载作用下的恢复力模型与破坏机理、静轴力作用下构件破坏机理与偏心影响以及组合作用产生的机理,为格构机理模型的验证提供支持。 (3)分析了构件在水平循环荷载和静轴力作用下的屈曲行为与破坏机理,提出了冷弯薄壁C型构件格构机理模型,并通过数值与试验,验证了其合理性。基于格构机理模型,将薄壁构件与一维杆件屈曲机理联系起来,分析了构件初始缺陷与板组效应的影响机理,得到了构件畸变屈曲半波长计算公式,并与经典方法和数值模拟进行了对比分析。 (4)在现有的相关屈曲模式定义下,推导了畸变变形与整体变形之间的变形相关关系。从变形协调角度出发,分析了相关屈曲产生的原因与机理,指出局部与畸变屈曲对截面参数的改变,是引起与整体屈曲相关作用的根本原因。同时形心与剪心偏移也是薄壁构件特有的现象。此外,定义了新的屈曲模式,重点区分了整体屈曲与畸变-整体相关屈曲,新的模式能更准确的反映构件屈曲行为。 (5)基于模型分析了构件在水平荷载作用下的破坏机理,过早地出现局部屈曲并产生集中性的理想塑性是冷弯薄壁型钢C型构件在压弯循环荷载作用下破坏的根本原因。此外,进行了恢复力模型推导与拟合,提出了反映屈曲影响的双刚度准则,得到了影响滞回性能的重要参数。 (6)基于格构机理模型,推导畸变临界力的解析解,选择直接对转动刚度进行数值拟合的方法,得到弹性畸变临界力的简化计算表达式。定义了畸变域范围,可根据构件截面参数,直接判断构件破坏模式,简化设计过程。基于机理分析,通过对整体屈曲惯性矩进行折减来考虑畸变屈曲的相关影响,推导拟合了简化设计公式,并与原DSM设计法和试验资料作对比,具备良好的精度。
[Abstract]:With the development of city and new countryside construction, especially the authoritative departments of the state have clearly pointed out that the new round of GDP growth mainly comes from the urbanization of rural areas. As a branch of industrialized light-weight steel structure, steel structure system attracts much attention. Its most remarkable advantage is that the construction cycle is short, which can improve the investment benefit and speed up the capital turnover; and the occupancy rate of construction site, construction waste, construction noise and so on are greatly reduced. At present, cold-formed thin-walled steel has been widely used in Low-Rise civil buildings. Its advantages are light weight, and with the progress of manufacturing technology, yield strength is getting higher and higher, and durability is getting better and better. At the same time, cold-formed thin-walled steel construction. Convenience is also incomparable with other traditional steel structures. These characteristics make cold-formed thin-walled steel has great advantages and development prospects in the background of industrialization of steel structure housing and construction of new countryside.
In this paper, the cold-formed thin-walled steel C-shaped members with the most extensive application and the highest degree of industrialization are selected as the research object. It is considered that there are still some worthy research points in the existing research on buckling mechanism, hysteretic behavior and design methods suitable for various sections.
(1) Based on Shanley's model, the whole process of one-dimensional bar buckling is deduced, and the buckling mechanism and influencing factors, including initial imperfections and section parameters, are analyzed in depth. On this basis, plasticity is divided into ideal plasticity and distributed plasticity according to the distribution of plastic region. At the same time, based on the buckling model, the relationship between R (plastic stiffness or post-buckling stiffness) and the buckling and plastic behavior of the members is analyzed, which is prepared for the buckling mechanism analysis of thin-walled members.
(2) Experiments and numerical simulations of cold-formed thin-walled C-shaped members are carried out, including hysteretic behavior under horizontal cyclic loading, buckling behavior and failure characteristics under static axial force, and composite action under static and cyclic loading. Complex force model and failure mechanism, failure mechanism and eccentricity effect of components under static axial force, as well as the mechanism of combination action, provide support for the verification of lattice mechanism model.
(3) The buckling behavior and failure mechanism of members subjected to horizontal cyclic load and static axial force are analyzed, and the lattice mechanism model of cold-formed thin-walled C-shaped members is proposed. The rationality of the lattice mechanism model is verified by numerical and experimental results. The influence mechanism of plate group effect is studied, and the formula for calculating half-wavelength of distortional buckling of members is obtained, which is compared with the classical method and numerical simulation.
(4) Based on the existing definition of buckling modes, the relationship between deformation and deformation is deduced. From the point of view of deformation compatibility, the causes and mechanism of buckling are analyzed. It is pointed out that the change of cross-section parameters caused by local buckling and distortion buckling is the fundamental cause of buckling. In addition, a new buckling mode is defined to distinguish the global buckling from the distortion-global buckling, which can more accurately reflect the buckling behavior of thin-walled members.
(5) The failure mechanism of cold-formed thin-walled C-section steel members subjected to horizontal loads is analyzed based on the model. The premature local buckling and the concentrative ideal plasticity are the fundamental reasons for the failure of cold-formed thin-walled C-section steel members subjected to cyclic compression and bending loads. The important parameters affecting the hysteretic behavior are obtained.
(6) Based on the lattice mechanism model, the analytical solution of the distortional critical force is deduced, and the simplified calculation formula of the elastic distortional critical force is obtained by directly fitting the rotational stiffness. Considering the influence of distortion buckling, the simplified design formula is deduced and fitted by reducing the integral buckling moment of inertia. The simplified design formula is compared with the original DSM design method and the experimental data, and has good accuracy.
【学位授予单位】：北京交通大学
【学位级别】：博士
【学位授予年份】：2013
【分类号】：TU392.1
本文编号：2206249
[Abstract]:With the development of city and new countryside construction, especially the authoritative departments of the state have clearly pointed out that the new round of GDP growth mainly comes from the urbanization of rural areas. As a branch of industrialized light-weight steel structure, steel structure system attracts much attention. Its most remarkable advantage is that the construction cycle is short, which can improve the investment benefit and speed up the capital turnover; and the occupancy rate of construction site, construction waste, construction noise and so on are greatly reduced. At present, cold-formed thin-walled steel has been widely used in Low-Rise civil buildings. Its advantages are light weight, and with the progress of manufacturing technology, yield strength is getting higher and higher, and durability is getting better and better. At the same time, cold-formed thin-walled steel construction. Convenience is also incomparable with other traditional steel structures. These characteristics make cold-formed thin-walled steel has great advantages and development prospects in the background of industrialization of steel structure housing and construction of new countryside.
In this paper, the cold-formed thin-walled steel C-shaped members with the most extensive application and the highest degree of industrialization are selected as the research object. It is considered that there are still some worthy research points in the existing research on buckling mechanism, hysteretic behavior and design methods suitable for various sections.
(1) Based on Shanley's model, the whole process of one-dimensional bar buckling is deduced, and the buckling mechanism and influencing factors, including initial imperfections and section parameters, are analyzed in depth. On this basis, plasticity is divided into ideal plasticity and distributed plasticity according to the distribution of plastic region. At the same time, based on the buckling model, the relationship between R (plastic stiffness or post-buckling stiffness) and the buckling and plastic behavior of the members is analyzed, which is prepared for the buckling mechanism analysis of thin-walled members.
(2) Experiments and numerical simulations of cold-formed thin-walled C-shaped members are carried out, including hysteretic behavior under horizontal cyclic loading, buckling behavior and failure characteristics under static axial force, and composite action under static and cyclic loading. Complex force model and failure mechanism, failure mechanism and eccentricity effect of components under static axial force, as well as the mechanism of combination action, provide support for the verification of lattice mechanism model.
(3) The buckling behavior and failure mechanism of members subjected to horizontal cyclic load and static axial force are analyzed, and the lattice mechanism model of cold-formed thin-walled C-shaped members is proposed. The rationality of the lattice mechanism model is verified by numerical and experimental results. The influence mechanism of plate group effect is studied, and the formula for calculating half-wavelength of distortional buckling of members is obtained, which is compared with the classical method and numerical simulation.
(4) Based on the existing definition of buckling modes, the relationship between deformation and deformation is deduced. From the point of view of deformation compatibility, the causes and mechanism of buckling are analyzed. It is pointed out that the change of cross-section parameters caused by local buckling and distortion buckling is the fundamental cause of buckling. In addition, a new buckling mode is defined to distinguish the global buckling from the distortion-global buckling, which can more accurately reflect the buckling behavior of thin-walled members.
(5) The failure mechanism of cold-formed thin-walled C-section steel members subjected to horizontal loads is analyzed based on the model. The premature local buckling and the concentrative ideal plasticity are the fundamental reasons for the failure of cold-formed thin-walled C-section steel members subjected to cyclic compression and bending loads. The important parameters affecting the hysteretic behavior are obtained.
(6) Based on the lattice mechanism model, the analytical solution of the distortional critical force is deduced, and the simplified calculation formula of the elastic distortional critical force is obtained by directly fitting the rotational stiffness. Considering the influence of distortion buckling, the simplified design formula is deduced and fitted by reducing the integral buckling moment of inertia. The simplified design formula is compared with the original DSM design method and the experimental data, and has good accuracy.
【学位授予单位】：北京交通大学
【学位级别】：博士
【学位授予年份】：2013
【分类号】：TU392.1
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