纤维模型在FRP加固结构分析中的应用与研究

发布时间：2018-03-12 17:01

本文选题：纤维模型　切入点：FRP　出处：《湖南大学》2015年硕士论文　论文类型：学位论文

【摘要】：近年来,纤维增强复合材料(fiber reinforced polymer,简称FRP)由于其优越的力学性能和物理性能,已经广泛地用于加固构件和结构中,特别是震后结构的修复工作,FRP的约束作用不仅能提高结构的承载力,还能大幅提高结构在地震作用下的耗能能力和延性。为研究结构经过FRP加固后抗震性能的变化,国内外学者对FRP加固技术进行了大量的研究,但是这些研究主要集中在材料与构件层面,并不能在结构层面上反映结构经过FRP加固后抗震性能的变化。针对目前FRP加固混凝土结构抗震性能研究的不足,本文借助Open Sees平台中基于柔度法的非线性梁柱单元结合纤维模型对FRP加固混凝土结构在地震作用下的时程响应进行模拟分析。研究以FRP约束混凝土材料的本构模型研究为切入点,以FRP约束混凝土柱构件的抗震性能模拟与研究为基础,基于Open Sees平台结合自主编制的FRP约束混凝土材料本构模型计算模块,采用纤维模型对FRP约束混凝土框架结构在地震作用下的响应进行了模拟与分析研究。本文主要研究内容如下:(1)在材料层面,介绍了现有的典型FRP约束混凝土材料本构模型,在此基础上,通过考虑材料属性对FRP约束混凝土材料极限状态的影响,引进了FRP材料有效利用系数,使本构模型能够准确地预测FRP在约束混凝土柱时材料的极限状态,同时考虑了横向箍筋在FRP约束混凝土柱中对混凝土材料的约束作用,提出了本文的FRP约束混凝土圆柱及矩形柱的材料本构模型。(2)在构件层面,基于Open Sees平台编制了FRP约束混凝土材料的计算模块,采用纤维模型对FRP约束混凝土柱在不同受力状态下的力学性能进行模拟与分析,探讨了钢筋本构关系、FRP材料厚度、轴压比、混凝土强度、纵筋配筋率、倒角半径和截面长宽比对FRP约束混凝土柱抗震性能的影响。(3)在结构层面,首先通过对FRP加固钢筋混凝土框架结构试件的模拟,论证了本文纤维模型的准确性,在此基础上,设计了一钢筋混凝土框架结构,在FRP加固总量相同的情况下,采用三种加固方案对设计的框架结构进行加固,采用纤维模型模拟得出了结构加固前后在地震作用下的弹塑性时程响应,通过分析对比不同加固方案下结构的顶层位移时程响应、基底剪力时程响应和层间位移角变化,得出不同加固方案对结构抗震性能的影响,提出了最为适合的加固方案。
[Abstract]:In recent years, fiber reinforced polymer (FRP) has been widely used in strengthening members and structures because of its excellent mechanical and physical properties. In particular, the post-earthquake repair of structures can not only improve the bearing capacity of structures, but also greatly improve the energy dissipation capacity and ductility of structures under earthquake. In order to study the change of seismic behavior of structures strengthened by FRP, Scholars at home and abroad have done a lot of research on FRP reinforcement technology, but these studies mainly focus on the material and component level. It can not reflect the change of seismic behavior of the structure strengthened by FRP on the structural level. Aiming at the deficiency of the research on the seismic behavior of concrete structure strengthened by FRP at present, In this paper, the nonlinear Liang Zhu element combined with fiber model based on flexibility method in Open Sees platform is used to simulate and analyze the time history response of concrete structure strengthened by FRP under earthquake. The constitutive model of concrete material confined by FRP is studied. Type A research as a starting point, Based on the simulation and study of seismic behavior of FRP confined concrete column members, the constitutive model of FRP confined concrete material is calculated based on Open Sees platform. The response of FRP confined concrete frame structure under earthquake is simulated and analyzed by using fiber model. The main contents of this paper are as follows: 1) at the material level, the existing constitutive model of typical FRP confined concrete material is introduced. On this basis, by considering the effect of material properties on the limit state of FRP confined concrete material, the effective utilization coefficient of FRP material is introduced, so that the constitutive model can accurately predict the limit state of FRP material in confined concrete columns. At the same time, considering the effect of transverse stirrups on concrete materials in FRP confined concrete columns, the material constitutive model of FRP confined concrete columns and rectangular columns is proposed in this paper. Based on Open Sees platform, the calculation module of FRP confined concrete material is developed. The mechanical properties of FRP confined concrete columns under different loading conditions are simulated and analyzed by fiber model. The constitutive relation of steel bar and the thickness of FRP material and axial compression ratio are discussed. The influence of concrete strength, reinforcement ratio of longitudinal reinforcement, chamfer radius and ratio of cross-section length to width on seismic behavior of FRP confined concrete columns. The veracity of the fiber model in this paper is demonstrated. On this basis, a reinforced concrete frame structure is designed. Under the condition of the same amount of FRP reinforcement, three reinforcement schemes are adopted to reinforce the designed frame structure. The elastoplastic time-history responses of structures under seismic action before and after strengthening are obtained by using fiber model. By analyzing and comparing the time-history responses of the top floor displacement, the base shear response and the interstory displacement angle of the structures under different reinforcement schemes, the elastic and plastic responses of the structures before and after strengthening are obtained. The effects of different reinforcement schemes on seismic behavior of structures are obtained, and the most suitable reinforcement schemes are put forward.
【学位授予单位】：湖南大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU37;TU599

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