钢框架梁柱节点在强震作用下的损伤性能研究（英文）

发布时间：2018-11-21 12:42

【摘要】：目的:钢框架焊接梁柱节点在地震作用下往往容易产生脆性裂纹,裂纹的发展和损伤累积将导致节点延性降低,发生脆性断裂。本文旨在探究节点在地震往复荷载作用下的损伤性能,分析其主要影响因素,提出有效的损伤评估模型,为后续节点损伤数值模拟提供基础,为钢框架的抗震设计提供参考。创新点:1.通过足尺节点试验,分析加载幅值、加载历程和荷载峰值对节点损伤性能的影响;2.基于试验结果,标定并验证3种经验损伤演化模型,提出基于疲劳断裂力学的节点损伤评估模型。方法:1.通过对9个足尺梁柱节点试件开展往复加载试验,包括5种变幅加载制度及4种常幅加载制度,分析加载幅值、加载历程和荷载峰值对节点损伤性能的影响;2.基于试验结果,根据节点损伤特点,在能量模型基础上,推导并拟合适用于节点循环加载的双参数损伤演化方程,并与其他模型进行比较,以验证其准确性;3.结合疲劳和延性断裂理论,依据损伤机理,定义"有效塑性应变"量化损伤过程,并以疲劳裂纹发展公式为基础,推导适用于计算在极低周循环荷载下节点损伤过程的损伤演化方程。结论:1.加载跨幅对节点性能影响较小;加载历程的影响与历程中峰值位移循环次数密切相关;突发性的强峰值对节点造成的损伤最大。2.节点损伤过程为幂函数形式;通过比较表明,在能量模型基础上推导出的适用于节点循环加载的双参数损伤演化方程,相对于单参数线性模型,能够更准确模拟节点在极低周循环下的损伤过程。3.基于疲劳断裂力学理论的损伤演化方程物理意义明确,能够描述节点循环损伤试验中所表现出的加速损伤及"损伤拐点"特征。
[Abstract]:Aim: it is easy to produce brittle crack in welded Liang Zhu joints of steel frame under earthquake. The development and damage accumulation of cracks will lead to the reduction of ductility and brittle fracture of joints. The purpose of this paper is to investigate the damage performance of joints under seismic reciprocating loads, to analyze the main influencing factors, to put forward an effective damage assessment model, to provide a foundation for numerical simulation of joint damage and to provide a reference for the seismic design of steel frames. Innovation: 1. Through full-scale joint test, the effects of loading amplitude, loading history and load peak value on the damage performance of the joint are analyzed. 2. Based on the experimental results, three kinds of empirical damage evolution models are calibrated and verified, and a joint damage assessment model based on fatigue fracture mechanics is proposed. Methods: 1. Through the reciprocating loading tests on 9 full-scale Liang Zhu joint specimens, including five variable amplitude loading systems and four constant amplitude loading systems, the effects of loading amplitude, loading history and load peak value on the damage performance of joints are analyzed. 2. Based on the experimental results and according to the damage characteristics of the nodes, the two-parameter damage evolution equation suitable for cyclic loading of nodes is derived and fitted on the basis of the energy model, and compared with other models to verify its accuracy. 3. Combined with the theory of fatigue and ductile fracture, according to the damage mechanism, the quantitative damage process of "effective plastic strain" is defined, and the fatigue crack development formula is used as the basis. The damage evolution equation is derived for calculating the damage process of nodes under extremely low cyclic loads. Conclusion: 1. The effect of loading span amplitude on node performance is small; the influence of loading history is closely related to the number of peak displacement cycles in the history; the damage caused by sudden strong peak value is the biggest. 2. 2. The damage process of nodes is in the form of power function. Compared with the single parameter linear model, the two-parameter damage evolution equation derived on the basis of the energy model can more accurately simulate the damage process of the node under the extremely low cycle. The physical meaning of the damage evolution equation based on fatigue fracture mechanics theory is clear, and it can describe the accelerated damage and "damage inflection point" characteristic in cyclic damage test of nodes.
【作者单位】： College
【基金】：Project supported by the National Natural Science Foundation of China(Nos.51708549,51678339,and 51378289)
【分类号】：TU391

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