锈蚀钢筋疲劳性能研究

发布时间：2018-04-17 21:49

本文选题：循环荷载 + 钢筋锈蚀　；参考：《浙江大学》2016年硕士论文

【摘要】：桥梁、吊车梁等钢筋混凝土结构,一方面受服役环境影响,内部钢筋会随时间的推移逐步发生锈蚀,另一方面受疲劳荷载作用,钢筋会累积疲劳损伤。因此,两者复合作用下,钢筋混凝土构件的破坏通常是锈蚀钢筋的疲劳断裂。为了掌握锈蚀钢筋的疲劳性能,本文以锈蚀钢筋为研究对象,利用通电加速锈蚀的方法获取锈蚀钢筋,开展锈蚀钢筋的疲劳试验以及数值模拟计算。主要研究内容包括：(1)基于逆向工程重建锈蚀钢筋的三维立体模型,分析了锈蚀钢筋的形态特征。分析结果表明随锈蚀率的增大,钢筋的锈坑数目和锈坑深度均有所增加。(2)对锈蚀钢筋进行轴向拉伸疲劳试验和疲劳断口分析,研究结果表明钢筋锈蚀后的应力幅值与疲劳寿命在双对数坐标下依然保持线性,锈蚀会导致疲劳寿命的显著下降；钢筋的疲劳断口可分为裂纹源区、裂纹发展区、临界过渡区和断裂区；疲劳裂纹萌生于钢筋表面锈坑,呈扇形向四周发展。(3)测试了钢筋疲劳过程中的磁信号变化规律,分析了磁信号变化与疲劳损伤之间的对应关系,发现钢筋在疲劳荷载作用下的磁场信号呈三阶段变化,可为钢筋的疲劳断裂预警提供新方法。(4)基于三维实体模型对锈蚀钢筋进行数值模拟,分析了锈蚀钢筋的疲劳性能。数值模拟获得的钢筋疲劳寿命与试验结果吻合较好,可为锈蚀钢筋的疲劳寿命计算提供参考。
[Abstract]:The reinforced concrete structures such as bridges, crane beams and so on are affected by the service environment on the one hand, and the internal steel bars will gradually corrode with the passage of time, on the other hand, under the action of fatigue load, the steel bars will accumulate fatigue damage.Therefore, the failure of reinforced concrete members is usually the fatigue fracture of corroded steel bars.In order to grasp the fatigue behavior of corroded steel bar, this paper takes corroded steel bar as research object, obtains corroded steel bar by means of electric accelerated corrosion, and carries out fatigue test and numerical simulation of corroded steel bar.The main research contents include: (1) based on the three-dimensional model of reverse engineering to reconstruct the corroded steel bar, the morphological characteristics of the corroded steel bar are analyzed.The results show that with the increase of corrosion rate, the number of rust pits and the depth of rust pits increase. 2) the axial tensile fatigue test and fatigue fracture analysis of corroded steel bars are carried out.The results show that the stress amplitude and fatigue life of steel bars after corrosion remain linear in logarithmic coordinates, corrosion will lead to a significant decrease of fatigue life, the fatigue fracture of steel bars can be divided into crack source region, crack development zone,The critical transition zone and fracture zone; the fatigue crack originates from the rust pit on the surface of steel bar, and develops in the shape of sector. The magnetic signal variation law during the fatigue process of steel bar is tested, and the corresponding relationship between the magnetic signal change and fatigue damage is analyzed.It is found that the magnetic field signal of steel bar under fatigue load changes in three stages, which can provide a new method for early warning of fatigue fracture of steel bar. The numerical simulation of corroded steel bar based on 3D solid model is carried out, and the fatigue performance of corroded steel bar is analyzed.The fatigue life of steel bar obtained by numerical simulation is in good agreement with the experimental results, which can provide a reference for the calculation of fatigue life of corroded steel bar.
【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TU375

【相似文献】