BRB式消能桁架的力学模型研究

发布时间：2018-07-17 05:33

【摘要】：桁框结构具有用钢量低,轻盈美观的特点,但其抗震性能较差,桁架容易发生整体失稳。BRB式消能桁框结构是用BRB替代桁架端部节间下弦杆,在地震作用较大时可以降低结构刚度,阻止能量的进一步输入,同时提高结构的延性。BRB式消能桁框结构具备了普通桁框结构的优点,且抗震性能优良,具有很高的研究价值和应用前景。本文针对BRB式消能桁框结构的力学模型展开研究。首先对BRB式消能桁框结构的设计提出假设,确定BRB屈服承载力的取值范围,实现基于性态的设计;然后从工程实际出发,利用3D3S软件设计一个四层桁框结构,选取第二层作为标准层进行研究;最后利用ABAQUS软件建立标准层的有限元模型,通过控制变量,重点研究桁架形式、腹杆连接方式、BRB屈服承载力和桁架高度等参数对结构承载能力、抗侧刚度、转动刚度和延性等力学性能的影响,并对BRB式消能桁框结构的设计方法进行验证。研究结果表明:(1)根据本文提供的设计方法,可以实现对BRB式消能桁框结构基于性态的设计,并且可以通过调整BRB的屈服承载力,实现各个楼层同步屈服;(2)当结构处于正常使用状态或地震荷载较小时,BRB式消能桁框结构具有较高的刚度和承载能力,与普通结构并无差别;当荷载达到一定程度时BRB率先屈服,在桁架端部形成塑性铰,能够降低结构刚度,阻止能量的进一步输入,提高结构的延性,有利于结构耗能和震后修复工作。(3)在BRB式消能桁框结构中,桁架有无竖腹杆和腹杆连接方式对结构的力学性能影响很小;BRB屈服承载力对力学性能的影响较大,在合理范围内提高BRB的屈服承载力,可以提高结构的承载能力、抗侧刚度、转动刚度和延性;桁架高度对结构的力学性能也有较大影响,相同条件下提高桁架的高度,可以明显提高结构的承载能力和刚度。最后,本文对ABAQUS的分析结果加以总结,给出了各参数对于BRB式桁框结构力学性能的影响,并针对本文存在的不足为后期研究提出了建议。
[Abstract]:The truss frame structure has the characteristics of low steel content, light and beautiful, but its seismic performance is poor. The truss structure is prone to overall instability. BRB type energy dissipation truss structure is used to replace the lower chord at the end of the truss. The stiffness of the structure can be reduced and the further input of energy can be prevented when the earthquake action is great. At the same time, the ductility. BRB type energy dissipation truss frame structure has the advantages of common truss frame structure, and the seismic performance is good. It has high research value and application prospect. In this paper, the mechanical model of BRB energy dissipation truss frame structure is studied. Firstly, the design assumption of BRB type energy dissipation truss frame structure is put forward, the range of BRB yield bearing capacity is determined, and the design based on property state is realized, and then a four-story truss frame structure is designed by using 3D3S software. The second layer is chosen as the standard layer, and the finite element model of the standard layer is established by Abaqus software. By controlling variables, the truss form is studied emphatically. The influence of the yield bearing capacity and truss height of BRB on the mechanical properties such as bearing capacity, lateral stiffness, rotational stiffness and ductility are discussed. The design method of BRB type energy dissipation truss frame structure is verified. The results show that: (1) according to the design method provided in this paper, the BRB type energy dissipation truss frame structure can be designed based on properties, and the yield bearing capacity of BRB can be adjusted. (2) when the structure is in normal condition or when the seismic load is small, the BRB truss frame structure has higher stiffness and bearing capacity, which is not different from the common structure, and when the load reaches a certain level, BRB takes the lead to yield. The plastic hinge formed at the end of the truss can reduce the stiffness of the structure, prevent the further input of energy, improve the ductility of the structure, and be beneficial to the energy dissipation and post-earthquake repair of the structure. (3) in the BRB type energy dissipation truss frame structure, Whether the truss has vertical webs or not has little influence on the mechanical properties of the structure. The yield bearing capacity of BRB has a great influence on the mechanical properties. In a reasonable range, the bearing capacity and lateral stiffness of the structure can be improved by increasing the yield bearing capacity of BRB. The stiffness and ductility of the truss and the height of the truss have great influence on the mechanical properties of the structure. The bearing capacity and stiffness of the structure can be obviously improved by increasing the height of the truss under the same conditions. Finally, this paper summarizes the analysis results of Abaqus, gives the influence of various parameters on the mechanical properties of BRB truss frame structure, and puts forward some suggestions for the later research in view of the shortcomings of this paper.
【学位授予单位】：山东建筑大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU391

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