防屈曲支撑内芯屈曲机理及整体稳定设计方法

发布时间：2018-04-28 03:18

  本文选题：防屈曲支撑 + 整体稳定性　； 参考：《哈尔滨工业大学》2015年博士论文

【摘要】：防屈曲支撑是一种利用软钢屈服来消耗地震能量的支撑构件,其兼具普通支撑和金属阻尼器的优点,小震下能够给结构提供附加刚度,大震下能实现全截面屈服消耗地震能量。防屈曲支撑的构成比较简单,主要由耗能内芯以及约束内芯屈曲的约束构件两部分组成。但是其屈曲机理却较为复杂,因为防屈曲支撑的整体与局部稳定性不仅与支撑的刚度、强度、内芯与约束构件的初始缺陷密切相关,而且受到内芯的弹塑性变形、内芯加强段、间隙以及内芯与约束构件间摩擦力等的影响,因此防屈曲支撑的分析与设计方法引起了相关学者的广泛兴趣。本文主要研究防屈曲支撑内芯屈曲机理以及在此基础上建立的支撑整体稳定设计方法,主要研究内容及结论如下:(1)对组合钢管混凝土式防屈曲支撑进行了五个试件的试验,包括足尺截面短试件试验、足尺试件试验、防屈曲支撑组合件试验以及对其构造形式改进后进行的波形验证试验。较为详细地介绍了这种形式防屈曲支撑的加工过程,指出了生产过程中需要注意的问题,通过试验发现了加工中容易出现的错误。对所提出的支撑形式进行了改进以使其应用到波形验证试验中,在内芯表面粘贴应变片测量了内芯在加载过程中的应变变化。(2)对防屈曲支撑的内芯屈曲机理进行了研究,建立了简化的防屈曲支撑分析模型,该模型假设约束构件为刚体且无初始缺陷,内芯为无初始缺陷的直杆。通过内芯的平衡微分方程及其边界条件,得到内芯挠度曲线和内芯与约束构件间接触力的表达式。通过对内芯弯矩的分析发现了其一点接触到两点接触转化的规律,本文给出了其临界力并进一步揭示了其向更多点接触转化的一般规律。对多点接触状态给出了接触点之间距离的表达式与最大接触力的公式,并据此给出了约束构件最大弯矩的计算公式,这是防屈曲支撑研究方面首次根据接触力与波长直接计算得到约束构件的最大弯矩。之后,给出了固结支撑的推导结果,并利用有限元软件对本章所提铰接及固结防屈曲支撑的波形变化过程与接触力公式进行了有限元验证。最后,利用有关学者对于压杆屈服后模量的理论,将弹性分析的结果扩展到塑性阶段,使用有限元模型的分析比较了折合弹性模量和切线模量的计算结果与模拟值的差别,给出了内芯屈服后模量取值的建议。(3)提出了一种考虑内芯屈曲模态的防屈曲支撑整体稳定设计方法,将简化的防屈曲支撑分析结果扩展到更一般性的情况。分析中引入了约束构件的刚度,因此考虑了约束构件变形,同时考虑了内芯加强段的影响。对内芯与约束构件同时列出平衡微分方程,并根据二者之间的变形协调条件得到一点与两点接触时内芯的挠度曲线,并得到内芯与约束构件接触力、约束构件最大弯矩和加强段最大弯矩的表达式。对其中使用的接触点处内芯切线斜率为零与弯矩为零的假设进行了参数分析验证,之后利用多点接触下约束构件的受力特征,将两点接触的分析扩展到更多点接触的情况,从而得到了更一般性的结论。为了简化计算过程,提出了计算最大接触力、约束构件和加强段最大弯矩的统一公式,并给出了约束构件与加强段的设计准则。(4)建立了带有端部的防屈曲支撑有限元模型,并在该模型中考虑约束构件变形,对本文所推导的结论进行了验证。在有限元分析中,首先检验了内芯由一点接触到多点接触的发展过程;然后,对内芯与约束构件间接触力的公式以及接触点之间的距离公式进行了检验,以验证其在考虑约束构件变形和加强段影响时其结论是否可用;最后,对约束构件弯矩等结论进行了检验。在有限元分析之后,利用本文所介绍的五个试件的试验结果对波长计算公式进行了验证。在完成了对本文理论的检验之后,对影响约束构件弯矩与加强段弯矩的关键参数进行了分析讨论,并与已有的相关设计方法进行了对比。
[Abstract]:Anti buckling support is a kind of support component which uses the yield of soft steel to consume seismic energy. It has the advantages of both common support and metal damper. Under small earthquakes, it can provide additional stiffness to the structure. Under large earthquakes, it can achieve full section yield and consume earthquake energy. The composition of anti buckling support is simple, mainly by energy dissipation inner core and inner core. The buckling constraint component is composed of two parts. But the buckling mechanism is more complex, because the overall and local stability of the buckling support is closely related not only to the stiffness, strength, and the initial defects of the inner core, but also to the elastic plastic deformation of the inner core, the inner core strengthening section, the gap and the friction between the inner core and the restrained member. The influence of force and so on, therefore the analysis and design method of buckling support has aroused wide interest of the relevant scholars. This paper mainly studies the buckling mechanism of the inner core of the anti buckling support and the design method of the supporting integral stability on this basis. The main contents and conclusions are as follows: (1) the concrete filled steel tube buckling restrained braces are carried out. The test of five specimens, including full scale section short test piece test, full scale test, anti buckling support combination test and waveform verification test after its structure improvement, introduced in detail the processing process of this type of buckling support, pointed out the problems needing attention during the production process, and found through the test. Errors that are easy to occur during processing are improved to make the support form to be applied to the test of waveform verification. The strain changes of the inner core during the loading are measured on the surface of the inner core. (2) the buckling mechanism of the inner core of the anti buckling support is studied, and a simplified analysis model of the buckling support is established. The model assumes that the constrained component is rigid and has no initial defects, and the inner core is a straight rod with no initial defects. Through the balance differential equation of the inner core and its boundary conditions, the inner core deflection curve and the indirect contact force of the inner core and the restraint member are obtained. In this paper, the critical force is given and the general law of its transformation to more contact points is further revealed. The expression of the distance between the contact points and the maximum contact force are given for the multi point contact state, and the calculation formula for the maximum bending moment of the restrained member is given. This is the first time that the research on the anti buckling support is based on the contact force and the contact force. The maximum bending moment of the constrained component is calculated directly by the wavelengths. After that, the derivation results of the consolidation support are given, and the finite element software is used to verify the wave change process and the contact force formula of the hinged and consolidated buckling support proposed in this chapter. Finally, the theory of the relative scholars' theory about the post yield modulus of the pressure bar will be used. The result of the analysis is extended to the plastic stage. Using the finite element model, the difference between the calculated results of the elastic modulus and the tangent modulus is compared with that of the simulated value. The suggestion of the value of the modulus of the inner core after yield is given. (3) an integral stability design method for flexion bracing with internal core buckling mode is proposed, which will simplify the anti flexion. The result of the analysis of the curved support extends to a more general case. The stiffness of the constrained component is introduced in the analysis, so the deformation of the constrained component is considered, and the influence of the inner core reinforcement is considered. The balance differential equation is listed for the inner core and the constrained component, and the inner core is obtained at the time of contact between the two and the two points. The deflection curve of the inner core and the constrained component is obtained and the maximum bending moment of the component is restrained and the maximum bending moment of the member is strengthened. The parametric analysis is carried out to verify the hypothesis that the slope of the core tangent of the inner core is zero and the bending moment is zero at the contact point at the contact point, and then the two points contact is divided by the stress characteristics of the multi point contact. In order to simplify the calculation process, a unified formula for calculating the maximum contact force, restricting components and strengthening the maximum bending moment of the section is proposed, and the design criteria of the restrained member and the reinforcement section are given. (4) a finite element model with end buckling support is set up, and the finite element model is established. In this model, the deformation of the constrained component is considered, and the conclusions derived in this paper are verified. In the finite element analysis, the development process of the inner core from one point contact to the multi point contact is tested first. Then, the formula of the indirect contact force between the inner core and the constrained component and the distance formula between the contact points are tested to verify that it is considered about about the contact point. In the end, the conclusion of the bending moment of the restrained member is tested. After the finite element analysis, the wavelength calculation formula is verified by the test results of the five specimens introduced in this paper. After the test of the theory of the present theory is completed, the bending moment and the bending moment of the constrained component are affected. The key parameters to enhance the bending moment are analyzed and discussed, and compared with the existing design methods.

【学位授予单位】：哈尔滨工业大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：TU352.1
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本文编号：1813531