【作者】 沈亚丽；

【导师】 肖岩； 郭玉荣；

【作者基本信息】 湖南大学 ， 结构工程， 2010， 硕士

【摘要】 钢管混凝土结-构由于具有一系列优越性能,目前在高层和超高层建筑中越来越多地被应用,然而对钢管混凝土抗冲击性能的研究还处于初步摸索阶段。近年来,建筑结构受冲击破坏的事件频繁发生。因此,对钢管混凝土结构的抗冲击性能研究变得十分必要。本文以钢管混凝土、约束钢管混凝土短柱为研究对象,对其在落锤冲击作用下的动力响应与破坏特征进行了试验和数值模拟两方面的研究,以全面了解构件在冲击荷载作用下的基本性能及影响因素。首先,本文对两种钢管壁厚、两种碳纤维层数的钢管混凝土及约束钢管混凝土短柱进行了一系列高度的轴向冲击试验,测得了冲击力时程曲线、试件轴向变形时程曲线、钢管表面各测点纵向、环向应变时程曲线及试件残余变形,并获得了试件最终变形形态,且用高速摄像仪全程记录了试件的破坏过程。在试验结果汇总的基础上,得出了平均轴向残余应变与冲击能量的关系。通过对比试件最终变形形态及核心混凝土的破坏形态,分析试件发生破坏的特征。讨论了钢管壁厚、冲击能量及碳纤维约束对试件最大冲击力、轴向变形及钢管应变的影响。基于试验结果,提出了计算最大冲击力及平均轴向残余应变的简化公式。其次,利用通用有限元分析软件ANSYS/LS-DYNA对试验进行数值模拟。将模拟得到的结果与试验结果相对比,发现两者能较好吻合,验证了模拟结果,也指出试验中存在的不足之处,并探讨了冲击过程中系统能量的变化规律及各种材料吸收能量的情况。更多还原

【Abstract】 Concrete filled steel tube (CFT) are wide used in high-rise and super high-rise buildings because of a series of superior properties. However, research on its impact resistant behavior is still at the beginning stage. In recent years, building structures damaged by the impact occur frequently. Therefore, research on the impact resistance of CFT structures become very necessary. In this paper, the dynamic response and the failure characteristics of CFT and confined concrete filled tube (CCFT) were studied by means of experiments and numerical simulation to fully understand the basic performance and influencing factors.Firstly, CFT and CCFT short columns with two kinds of steel tube wall thickness and layers of carbon fiber were tested under series of height in the axial direction, impact force history, axial deformation history, axial and circumferential strain history of measuring points on steel tube surface and residual deformation of the specimen were measured and obtained final deformation patterns of specimens, a high speed camera was used to record the whole damage process of specimens as well. The relationship between the average axial residual strain and impact energy was obtained. The characteristics of damage occurred in the specimens was analyzed by comparing the final deformation patterns of specimens and failure patterns of core concrete. The effectiveness of steel tube wall thickness, impact energy and carbon fiber constraint to the maximum impact force, axial deformation and strain of steel was discussed. The maximum impact force and average axial residual strain can be caculated by a simplified formula.Secondly, numerical simulation was conducted on the test using finite element analysis software ANSYS/LS-DYNA. The simulated results with experimental results were compared and found good agreement between the two. It verified the simulation results and pointed out the deficiencies in the test, the system energy transfer rules and energy absorption situation of all kinds of materials in the impact process were also discussed in the end.更多还原