内核分离式屈曲约束构件的设计理论与试验研究

发布时间：2018-06-23 06:38

本文选题：内核分离式屈曲约束构件 + 约束比　；参考：《清华大学》2015年博士论文

【摘要】：屈曲约束构件是消能减震理念在抗震工程中的一种典型应用,近年来在国内外得到广泛使用。本文提出一种新型的屈曲约束构件,其由两个分肢组成,每个分肢为一字形内核钢管约束的屈曲约束构件,分肢间由两侧沿纵向的连续腹板或若干缀板连接为整体,分别称为实腹型和缀板型内核分离式屈曲约束构件。该新型构件具有承载效率高、端部构造可靠等优点,适合大吨位屈曲约束构件的设计。首先对于实腹型内核分离式屈曲约束构件,凝练出反映内核间距、内核截面积、内核和外围抗弯刚度等因素的参数,利用平衡法推导不同边界条件下的弹性屈曲荷载。构件两端铰接时弹性屈曲变形介于正弦和余弦曲线之间,与几何尺寸有关,可利用能量法求得。对于缀板型内核分离式屈曲约束构件,将外围连续化后,考虑截面剪切变形的影响,推导得到简化的弹性屈曲荷载计算式。考虑整体几何初始缺陷,推导屈曲约束构件在轴压作用下考虑二阶效应的跨中弯矩。根据内核进入全截面屈服时,构件跨中弯矩不超过外围截面抗弯承载力的条件,建立起实用的约束比限值设计方法,可保证静力单调轴压下的整体失稳不先于内核全截面屈服发生。对比梁单元、点对点接触和面对面接触三种弹塑性有限元模型的计算结果,验证了简化有限元分析模型的合理性。引入屈曲约束构件的正则化长细比和稳定系数。利用有限元方法研究了内核分离式屈曲约束构件的弹性屈曲特性,并推导了缀板型构件的分肢正则化长细比计算式。基于弹塑性数值分析结果,拟合得到全正则化长细比范围的弹塑性承载力设计曲线。利用有限元滞回分析,研究了正则化长细比对滞回性能的影响。总结以上内容,将屈曲约束构件划分为耗能型不屈曲构件、承载型不屈曲构件和延迟屈曲构件,并给出了临界正则化长细比。研究了实腹型构件外围钢材屈服强度、几何初始缺陷、腹板高厚比等因素对受力性能的影响,建立起腹板强度设计方法。讨论了缀板型构件整体弹塑性失稳和分肢失稳的关系,提出了缀板强度验算方法。最后,对内核分离式屈曲约束构件进行了拉压滞回试验研究,验证了理论推导和有限元分析的合理性,对比了不同端部构造方案的可靠性,并且针对试验破坏形式提出了构件设计和加工中需要关注的问题,为工程应用提供参考。
[Abstract]:Buckling restrained member is a typical application of the idea of energy dissipation and damping in seismic engineering, which has been widely used at home and abroad in recent years. In this paper, a new type of buckling restraint member is proposed, which consists of two splitters, each with a zigzag core steel tube constraint, and is connected as a whole by a continuous web or a number of spliced plates along both sides along the longitudinal direction. They are called solid web type and plate type core split buckling constraint member respectively. The new component has the advantages of high loading efficiency and reliable end structure, which is suitable for the design of large tonnage buckling restrained members. Firstly, the parameters reflecting the space between the core, the cross section of the core, the bending stiffness of the core and the external bending are condensed for the separated buckling constraint members of the solid web kernel, and the elastic buckling loads under different boundary conditions are derived by the equilibrium method. The elastic buckling deformation is between sinusoidal and cosine curves when the two ends of the member are hinged, which is related to the geometric size and can be obtained by the energy method. A simplified formula for calculating elastic buckling load is derived by considering the effect of cross-section shear deformation on the separated buckling constrained members with a plate core. Considering the initial defect of the whole geometry, the bending moment of buckling restrained members under axial compression is derived. According to the condition that the mid-span bending moment of the member does not exceed the flexural bearing capacity of the peripheral section when the core enters the yield of the full section, a practical design method of the limit value of the constraint ratio is established. It can be ensured that the whole instability under the static monotone axial compression does not occur before the yield of the whole cross section of the core. Comparing the results of beam element, point-to-point contact and face-to-face contact, the rationality of the simplified finite element analysis model is verified. The regularization aspect ratio and stability coefficient of buckling constrained members are introduced. In this paper, the elastic buckling characteristics of the core separated buckling constrained members are studied by using the finite element method, and the formula of the segmental regularization ratio of length to slenderness of the split-plate members is derived. Based on the results of elastic-plastic numerical analysis, the design curve of elastic-plastic bearing capacity in the range of fully regularized slenderness ratio is obtained. The effect of regularized aspect ratio on hysteretic performance is studied by means of finite element hysteretic analysis. In this paper, the buckling constrained members are divided into energy-dissipation non-buckling members, load-bearing non-buckling members and delayed buckling members, and the critical regularized aspect ratio is given. In this paper, the influence of the external steel yield strength, geometric initial defect and the ratio of height to thickness of web plate on the mechanical properties of solid web members are studied, and the design method of web strength is established. The relationship between integral elastoplastic instability and split-limb instability of plate members is discussed, and a method for checking the strength of stiffened plates is put forward. Finally, the hysteretic tests of the separated buckling confined members of the kernel are carried out, which verify the rationality of the theoretical derivation and finite element analysis, and compare the reliability of different end-structure schemes. The problems in the design and manufacture of components are put forward, which can provide reference for engineering application.
【学位授予单位】：清华大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：TU352.1

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