无焊十字形截面屈曲约束支撑的试验研究

发布时间：2018-02-27 21:37

本文关键词： 屈曲约束支撑摩擦力十字形截面低周疲劳滞回性能接触应力　出处：《东南大学》2015年硕士论文　论文类型：学位论文

【摘要】：屈曲约束支撑(Buckling-restrained braces, BRBs)作为一种新型金属耗能元件,具有滞回性能稳定、耗能能力强、制作成本较低等优点,在国内外得到了越来越多的应用。本文针对BRB中仍然存在的一些问题进行了研究分析,并对屈曲约束支撑进行了优化设计,从而达到高性能BRB的要求。本文通过三批试件的低周疲劳试验研究了不同构造BRB的低周疲劳性能以及耗能能力,并对试验结果进行了对比分析。本文的主要内容如下：(1)对BRB中摩擦力的产生原因以及摩擦力的存在对BRB性能的影响进行了理论分析,采用Fortran程序对BRB核心部件的受力过程进行了模拟,并与试验结果相对比。结果表明,摩擦力的存在对BRB的性能有着重要影响。摩擦力的存在使得BRB核心部件中的应力应变分布不均,从而导致核心部件耗能分布不均,中间耗能多,两端耗能少,最终出现核心部件中部的断裂。另外摩擦力也是导致试件出现拉压不对称的主要原因。(2)为了减小BRB中的摩擦力,同时达到高性能BRB的要求,设计了第一批无焊十字形截面BRB。此批次试件的核心部件采用铸造工艺直接铸造成十字形截面,避免了焊接十字形截面中普遍存在的焊接残余应力。试验结果表明,该类BRB的滞回性能稳定,拉压不对系数满足规范要求,试验结果主要的不足是低周疲劳性能不好。本批试件达不到高性能BRB的要求,主要原因是铸造工艺达不到设计要求,导致试件上的缺陷较多,从而影响了低周疲劳性能。(3)鉴于第一批试件的经验教训,设计了第二批BRB试件,此批次试件的核心部件采用角钢拼接的十字形截面。由于本批次试验采用热轧角钢拼接的方法,避免了第一批试件中不可控缺陷的产生。试验结果表明,该类支撑的滞回性能稳定,第一根角钢断裂前,试件的累积塑性变形分别达到2165、4176和1957,远大于AISC的建议值200,满足高性能BRB的要求。此外在第一根角钢断裂后,剩余角钢仍具有耗能能力。三根试件的拉压不平衡系数均在1.1以下,满足AISC规定的1.3限值。(4)设计了三根表面带槽钢衬板的BRB试件和一根普通BRB试件,并进行了低周疲劳试验。试验结果表明,设计的四根BRB滞回性能稳定,低周疲劳性能较好,CPD均能达到2000以上,满足高性能BRB的要求。对于普通BRB,由于一字形截面容易产生多波屈曲,在波峰处的无粘结材料容易被拉裂损坏,从而导致试件的拉压不平衡系数在大幅值下超过规范规定的1.3限值：而对表面带槽钢衬板的BRB,由于钢与钢之间的摩擦系数较小,即使有的波峰处的无粘结材料发生了拉裂损坏,其拉压不平衡系数也能满足不超过1.3的要求。(5)对BRB构件进行了有限元模拟,表明采用ABAQUS可以较好模拟BRB的低周反复加载过程。此外,对BRB中的接触应力进行了理论分析以及有限元模拟。结果表明,BRB中的接触应力和核心部件的宽度没有关系,主要与核心部件的厚度有关,随着厚度的增加,接触区域面积增加,接触应力峰值显著减小。另外,约束部件的刚度对接触应力也有一定的影响,但是影响程度较小。根据模拟结果,给出了BRB中接触应力峰值的简化估计公式,可以根据该公式近似估计BRB的接触应力,从而合理选择约束砂浆或者混凝土的强度等级。
[Abstract]:The BRB (Buckling-restrained braces BRBs) is a new type of metal dampers, with stable hysteretic performance, energy dissipation capacity, low cost, has got more and more applications at home and abroad. This paper analysis on some problems still exist in the BRB, and the BRB were optimization design, so as to achieve the high performance requirements of BRB. The three batch of specimens of low cycle fatigue test of different structure BRB low cycle fatigue resistance and energy dissipation capacity, and the test results were compared and analyzed. The main contents of this paper are as follows: (1) effect on BRB friction causes, the existence of friction on the performance of BRB is analyzed by Fortran program loading process on BRB core components are simulated and compared with the experimental results. The results show that the friction force There has an important influence on the performance of BRB. The friction force due to the existence of BRB core components of the stress and strain distribution is uneven, resulting in uneven distribution of the core components of energy consumption, intermediate energy. Both ends of low energy consumption, ultimate fracture. In addition the central core components of friction is the main reason that lead to the tension asymmetry. (2) in order to reduce friction in BRB, and achieve the high performance requirements of BRB design, the first batch of non WELDED CRUCIFORM section BRB. of this batch of specimens of the core components of the casting process of direct casting into the shape of a cross section, avoid the weld cross section existed in the welding residual stress. The test results show that the BRB stable hysteretic performance, does not meet the standard requirements of tension and compression coefficient, the test results of main problems is the low cycle fatigue performance is not good. This batch of specimens did not reach the high performance requirements of BRB, the main raw Because the casting process can not meet the design requirements, to test more defects on, thus affecting the low cycle fatigue properties. (3) in view of the first batch of specimens of lessons, designed the second batch of BRB specimens, the core part of this batch of specimens with cruciform section. By the method to splice angle the batch test using hot rolling angle stitching, avoid the first batch of uncontrollable defects produced in the specimen. The experimental results show that this kind of support stable hysteretic performance, the first root angle before the fracture specimen cumulative plastic deformation were respectively 21654176 and 1957, higher than the recommended value of 200 AISC, to meet the high the performance of BRB. In addition in the first root fracture angle, the residual angle still has energy dissipation capacity. Three specimens tension imbalance coefficient is below 1.1, meet AISC regulations 1.3 limits. (4) design three root surface with steel lining board and a BRB specimen The ordinary BRB specimen, and the low cycle fatigue test was carried out. The results showed that four BRB lag design back to stable performance, low cycle fatigue performance, CPD could reach more than 2000, to meet the high performance requirements of BRB. For ordinary BRB, because the shape is easy to produce multi wave buckling, at the crest of the wave of no adhesive material is easy to crack damage, resulting in unbalanced coefficient in tension and compression test values significantly exceed the specification limits of 1.3 parts: on the surface of steel lined plate BRB, because the smaller friction coefficient between steel and steel, even without adhesive materials had some damage to crack at the crest, the pull pressure unbalance coefficient can also meet the requirements. No more than 1.3 (5) of the BRB component is simulated by finite element method, show that the cyclic loading process using ABAQUS can simulate BRB. In addition, the BRB of the contact stress is analyzed in theory and The finite element simulation. The results show that the BRB contact force Never mind and the core components of the main components and core width, thickness, with increasing thickness of the contact area increases, the contact stress peak decreased significantly. In addition, the restraint member stiffness on the contact stress has a certain impact, but a lesser extent. According to the simulation results, given the BRB contact should simplify the estimation formula of peak stress, according to the approximate formula for estimating the BRB contact stress, so as to choose the reasonable restraint strength grade of mortar or concrete.

【学位授予单位】：东南大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU317

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