地震作用下钢管混凝土桩损伤性能研究

发布时间：2018-04-22 14:19

本文选题：钢管混凝土桩 + 累积损伤　；参考：《西安工业大学》2015年硕士论文

【摘要】：由于良好的力学性能和抗震性能,钢管混凝土桩作为一种组合设计形式在地震区建筑中得到了广泛应用。对钢管混凝土桩抗震性能的研究一直是国内外的研究热点,许多研究者通过抗震试验对钢管混凝土的抗震性能进行了探讨。但是大部分研究者的侧重点都是放在钢管混凝土的承载力、滞回性能以及建立滞回模型的研究上,很少考虑地震作用下钢管混凝土桩的疲劳损伤,以及由于疲劳损伤的累积而导致的钢管混凝土的累积损伤破坏。本文针对钢管混凝土桩在地震荷载下的力学性能和疲劳累积损伤问题进行了数值模拟较为系统的理论分析。模拟结果表明钢管混凝土具有良好的抗震滞回性能和耗能能力,即使钢管混凝土产生了较大的变形也不会发生严重的承载力退化现象。钢管混凝土桩滞回曲线的荷载和刚度退化随着侧移率的增大而加快,说明在较大的变形条件下,往复变形一次对钢管混凝土造成的损伤也大；随着侧移率的减小,钢管混凝土的滞回耗能能力明显增强。研究表明,承受低周往复荷载作用的钢管混凝土桩在破坏时钢管断裂处的应变并没有达到单调拉伸时的极限应变,钢管是在拉应力和压应力的反复作用下产生了疲劳损伤,当钢管的损伤累积到一定程度时,最终发生疲劳断裂。本文建立了反映钢管混凝土桩低周疲劳寿命的改进Manson-Coffin关系模型,得出了钢管混凝土桩变形和疲劳寿命的关系曲线。与前人试验数据相比,理论曲线能够比较合理地反映这几类钢管混凝土桩在不同变形条件下的疲劳寿命。综合Miner的线性累积损伤理论和钢管混凝土桩的循环耗能规律,建立了钢管混凝土桩的基于耗能的改进线性累积损伤模型。基于连续介质损伤力学的基本理论和钢管混凝土的弹塑性分析,建立了钢管混凝土构件在单调荷载和低周往复荷载下的简化损伤梁单元模型,该损伤模型形式简单,具有明确的物理和力学意义,比较适合用于地震作用下的钢管混凝土桩的损伤分析。
[Abstract]:Because of good mechanical and seismic performance, concrete filled steel tube piles have been widely used in seismic area buildings as a combination design form. The research on seismic performance of concrete filled steel tube piles has been a hot topic at home and abroad. Many researchers have studied the seismic performance of steel tube concrete through seismic test. Most of the researchers focus on the bearing capacity of the concrete filled steel tube, the hysteretic behavior and the establishment of the hysteretic model, which seldom consider the fatigue damage of the concrete filled steel tube pile under the earthquake action, and the cumulative damage and damage of the concrete filled steel tube caused by the cumulative fatigue damage. The numerical simulation results show that the concrete filled steel tube has good seismic hysteretic performance and energy dissipation capacity. Even if the concrete filled steel tube has a larger deformation, it will not have serious bearing capacity degradation. The concrete filled steel tube pile is stagnant. The load and stiffness degradation of the back curve speed up with the increase of the lateral displacement, which indicates that under the larger deformation conditions, the damage of the concrete filled steel tube caused by reciprocating deformation is also great. With the decrease of the lateral displacement, the hysteretic energy dissipation capacity of the concrete is obviously enhanced. The research shows that the concrete filled steel tube pile under the low cycle reciprocating load is shown. The strain at the fracture of the steel pipe did not reach the limit strain at the time of monotonous tensile. The steel pipe produced fatigue damage under the repeated action of tensile stress and compressive stress. When the damage of the steel pipe accumulated to a certain extent, the fatigue fracture eventually occurred. This paper established an improved Manson-Cof to reflect the low cycle fatigue life of the steel pipe concrete pile. The relationship curve between the deformation and fatigue life of the concrete filled steel tube pile is obtained by the fin relation model. Compared with the previous experimental data, the theoretical curve can reasonably reflect the fatigue life of the concrete filled steel tube piles under different deformation conditions. The linear cumulative damage theory of Miner and the cyclic energy dissipation law of the concrete filled steel tube pile are built. An improved linear cumulative damage model based on energy dissipation is established for concrete filled steel tube piles. Based on the basic theory of continuous medium damage mechanics and elastoplastic analysis of concrete filled steel tubes, a simplified model of damaged beam element is established for concrete filled steel tubular members under monotonic load and low cycle reciprocating load. The damage model is simple and has a definite form. Physical and mechanical significance is more suitable for damage analysis of concrete-filled steel tubular piles under earthquake.

【学位授予单位】：西安工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU435;TU473.1

【参考文献】