古建筑木结构榫卯节点及柱架滞回性能有限元分析

发布时间：2018-01-11 03:10

本文关键词：古建筑木结构榫卯节点及柱架滞回性能有限元分析　出处：《西安建筑科技大学》2015年硕士论文　论文类型：学位论文

【摘要】：古建筑具有极高的文化、历史和社会价值,而古建筑木结构在悠久的历史中累积了变形、损伤和材料老化,且有随时间增长而恶化的趋势,因此亟待对其进行结构的安全评估和修缮。榫卯连接是我国古建筑木结构构件间常用的连接方式,是主要特色之一,在地震作用下,榫卯间的挤压摩擦起到良好的消能减震作用。而榫卯节点的破坏通常会导致整体结构倾斜甚至倒塌。因此,研究榫卯节点及构架的滞回性能对鉴定评估和修缮加固现存古建筑木结构具有重要意义。基于已有的试验研究结果,本文以典型单向直榫节点、透榫节点和透榫连接的柱架为研究对象,建立了能够分析其传力机理和滞回性能的有限元模型。单向直榫节点有限元模型计算得到的破坏模式,节点转角大于0.02rad时的转角-弯矩滞回曲线和骨架曲线与试验结果吻合较好,刚度退化和等效粘滞阻尼系数均与试验结果接近,有限元模型的有效性得到了验证。通过分析往复加载过程中榫卯间的接触应力与接触状态的变化规律,得到了其接触压力与摩擦力的变化规律,揭示了榫卯间通过的接触、摩擦和滑移抵抗外力的机理。本文有限元模型计算得到透榫节点及透榫节点柱架的滞回曲线、骨架曲线也与试验结果吻合较好。基于已验证的单向直榫节点有限元模型,分析了木材材性、摩擦系数和榫头拔出量等参数对其滞回性能的影响规律。模拟分析结果表明增大木材横纹弹性模量,节点的初始刚度和加载结束时的最大承载力增大,耗能能力增强,但顺纹弹性模量对节点的滞回性能影响不大。木材间摩擦系数越大,节点的滞回曲线越饱满,耗能能力越强;节点的刚度和承载力亦增大,但增幅较小。榫头拔出得越多,节点的滞回性能不同程度的变差,承载力显著降低,变形能力变差,节点刚度降低,而耗能能力变化不大。
[Abstract]:Ancient buildings have a high cultural, historical and social value, while ancient wooden structures have accumulated deformation, damage and material aging in a long history, and there is a tendency of deterioration with the increase of time. Therefore, it is urgent to carry out structural safety assessment and repair. Mortise and tenon connection is one of the main characteristics of wood structural components of ancient buildings in China, and it is one of the main characteristics under the earthquake action. The squeezing friction between tenon and joint plays a good role in energy dissipation and shock absorption. The damage of tenon and joint usually leads to the whole structure tilting or even collapsing. It is very important to study hysteretic performance of tenon joint and frame to evaluate and repair and strengthen the existing ancient building wood structure. Based on the existing experimental results, the typical unidirectional tenon joint is used in this paper. The finite element model which can analyze the force transfer mechanism and hysteretic performance is established. The failure mode of unidirectional straight tenon joint is obtained by calculating the finite element model. The angular bending hysteretic curve and skeleton curve are in good agreement with the experimental results, and the stiffness degradation and equivalent viscous damping coefficient are close to the experimental results. The validity of the finite element model is verified. By analyzing the change of contact stress and contact state between tenon and joint during reciprocating loading, the law of contact pressure and friction is obtained. The mechanism of contact, friction and slip resistance to external force is revealed. The hysteretic curves of tenon joint and post frame are calculated by finite element model in this paper. The skeleton curve is also in good agreement with the experimental results. Based on the verified unidirectional tenon joint finite element model, the wood properties are analyzed. The effects of friction coefficient and tenon pull-out on the hysteretic properties of the joints are studied. The simulation results show that the initial stiffness of the joints and the maximum bearing capacity at the end of loading increase with the increase of the elastic modulus of wood transverse grain. The higher the friction coefficient between wood, the fuller the hysteretic curve and the stronger the energy dissipation ability. The stiffness and bearing capacity of the joint also increased, but the increase was small. The more the mortise was pulled out, the worse the hysteretic performance of the joint was, the lower the bearing capacity, the worse the deformation capacity and the stiffness of the joint. However, the energy consumption capacity does not change much.
【学位授予单位】：西安建筑科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU366.2

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