【作者】 李晓东；

【导师】 王秀丽；

【作者基本信息】 兰州理工大学 ， 结构工程， 2008， 博士

【摘要】 屈曲约束支撑在轴压荷载作用下屈服而不屈曲,具有良好的滞回性能和耗能特性,已在不少工程中应用,是一种很具有发展潜力的耗能减震元件,具有良好的发展应用前景。但屈曲约束支撑的核心技术属私人所有,且国外核心构件一般采用极低屈服点钢材,这种钢材在我国尚未大量生产。本文基于屈曲约束支撑的基本原理,结合我国国情,采用国产钢材作为支撑构件,基于经典理论对屈曲约束支撑构件研究了其静力和动力性能,进行了6个构件的模型试验,验证了相应的理论,同时采用ANSYS软件进行数值模拟,探讨了相关参数的影响,最后提出在大跨度钢拱和网壳结构中采用,分析了此类结构的减震效果。研究结果表明,本文提出的新型屈曲约束支撑具有良好的力学性能,可直接用于实际工程,同时带有屈曲约束支撑的大跨度钢拱和网壳结构较常规的同类结构具有明显的减震效果,提高了大跨度结构的安全度。本文主要进行了以下工作:(1)基于屈曲约束支撑的基本原理,提出新型的纯钢型支撑型式,推导了多点支承型和连续支承型屈曲约束支撑整体稳定承载力计算公式,得到了对侧向支承的数量及刚度限值;利用MATLAB软件分析了加强区的刚度和长度对内核构件临界荷载的影响,给出了初始几何缺陷、宽厚比、长细比、支座条件对其稳定性的影响公式。(2)首次进行了屈曲约束支撑的动力稳定性研究,分析了不同类型屈曲约束支撑的动力稳定性、耗能能力和纵向振动性能,得到侧向支承的刚度及动力稳定性相关的结论。(3)进行不同类型的构件的试验研究,提出带圆弧翼缘十字板式和双管式纯钢型屈曲约束支撑型式,进行模型试验。研究了构件的滞回性能与单向加载时的力学性能,试验结果表明,连续支承型屈曲约束支撑具有较好的耗能能力。同时,在本试验中,也对混凝土屈曲约束支撑进行了对比试验分析,结果表明,连续支承能够增强构件的耗能能力。(4)利用ANSYS有限元软件,对带圆弧翼缘十字式和双管式纯钢型屈曲约束支撑进行数值模拟,验证该元件的力学性能,表明理论分析与试验研究结果规律相同。此外,通过ANSYS进行大量参数分析,探讨了侧向支承的数量、外包构件的刚度、加强区的刚度、宽厚比、长细比等参数的影响。计算结果表明,侧向支承的数量及外包构件与内核构件的刚度比是影响屈曲约束支撑临界承载力的关键因素。(5)提出在大跨度钢拱结构中采用屈曲约束支撑的减震体系,计算了大跨度钢拱结构在三维地震激励下,在不同布置方式时结构的地震响应,分析了不同的抗震设防烈度、不同的地震波输入、矢跨比变化对减震效果的影响;考察了结构在不同长宽比、不同支承条件、是否有无下部结构等参数变化对减震效果的影响。计算结果表明,当屈曲约束支撑为混合布置时,恰当地选择钢拱结构的矢跨比,减震效果最佳。更多还原

【Abstract】 Buckling Restrained Brace (BRB) yield but not buckling under axial compression loads, performs good hysteretic properties and energy dissipation. Now it is applied to new buildings and reinforcement of existing buildings. However, all core technologies of BRB are private; the core components of BRB generally use low-yield point of steel, it has not yet been produced in China; based on the current principle of BRB, researchers design this braces by domestic steel, but lack of a large number of system testing and research; in addition, the main research of BRB focus on the framework and less on the large-span structure, the applied research on the large-span steel arch structure is still not found. Therefore, based on the research by domestic and international, this paper study the mechanical properties of BRB using theoretical analysis and experimental methods, conduct a comprehensive analysis in the large-span steel arch structure the first, perform parametric analysis. Four parts are study as follows: (1) The mechanical properties of BRB is comprehensive analyzed. The global stability for pure steel and concrete type of BRB is studied, the number of lateral stiffness and requirements of BRB are obtained with the calculation formula; compare the stiffness requirements of outer tube for two different types BRB; by use of MATLAB software, the influence of stiffness and length of stiffen regions under the critical load for core member are given; the stability of the formula are given, in which the initial geometric defect, width-to-thickness ratio, slenderness ratio; boundary conditions are considered; the hysteretic curve of the simulation equation is conducted; the dynamic stability is analyzed combined with the components that used in the experiment, the results shown that the bigger of lateral rigidity, the better of its dynamic stability. In additional, reliability problem of BRB is discussed. (2) The FEM simulation of BRB. By ANSYS software, 17 entities finite element model is selected, under pure steel and concrete type of BRB, the hysteretic curve and load-displacement curve of axial compression are investigated; the mechanical properties of BRB under different parameters, including the number of lateral braces, the stiffness of outer tube, the stiffness of stiffen regions, width-to-thickness ratio, slenderness ratio. Comparison with the test results, it shows that theoretical analysis and experimental has the same tendency, but there are certain differences in values. (3) The experiment research. Four pure steel and one concrete components were selected, the hysteretic curve and load-displacement curve of axial compression are researched, the results of theoretical analysis and ANSYS analysis is compared, it is showed that generally difficult to achieve the design requirements for the single point-support of BRB because of stiffiiess degradation, however, the continuous support of BRB has a good hysteretic performance and better energy dissipation, also verified the construction of concrete BRB used in this test meet the requirements. (4) the vibration analysis in large-span steel arch structure with BRB. Under 3-D seismic excited, the effect of different arrangement of BRB, seismic fortification intensity, seismic waves, height-span ratio, length-width ratio, boundary conditions, substructure influence are studied. The results showed it has some influence on the vibration of large-span steel arch structure with BRB, but its effect subject to a greater impact on these parameters.更多还原