锈蚀分级下平行钢丝的疲劳强度试验研究及数值分析
发布时间：2018-07-25 18:59
【摘要】：对于现代缆索体系桥梁来说,缆索系统是其主要承重构件。大量工程实例表明,桥梁服役过程中,在循环荷载和腐蚀环境的协同交互作用下,拉索极易发生腐蚀疲劳损伤破坏,直接原因就是钢丝的腐蚀或腐蚀疲劳导致了拉索的力学性能和承载能力的下降,严重威胁着桥梁结构的安全性。对锈蚀分级下钢丝的承载能力和疲劳寿命进行深入研究,既能保证拉索在桥梁运营期间具有较高的安全性,又能在合适的时间内进行拉索的更换,减少经济损失,延长桥梁结构的使用寿命,这是本文研究的主要目的。本文主要研究内容概括如下:(1)研究了拉索平行钢丝的锈蚀特性,分析了拉索钢丝锈蚀的过程,结合人工加速钢丝锈蚀试验后的结果,对钢丝锈蚀程度进行分级,为开展锈蚀分级下钢丝的疲劳性能试验研究提供基础。(2)统计了钢丝蚀坑的三维尺寸,研究蚀坑的深度、长度和宽度3个参数的分布特征;然后用有限元方法对典型半椭圆形蚀坑的应力集中系数进行了系统的数值分析。(3)对不同锈蚀等级的钢丝进行了疲劳试验,得出疲劳寿命S-N曲线,研究了锈蚀程度对钢丝疲劳寿命的影响。结合腐蚀疲劳试验的结果和钢丝断口的扫描电镜图片分析,研究了钢丝的腐蚀疲劳断裂机理。研究带有表面裂纹钢丝的应力强度因子,得到了拉伸荷载下裂纹扩展应力强度因子几何修正系数的统一表达式。研究比较分析了带有表面裂纹损伤的钢丝剩余强度。(4)研究分析拉索钢丝腐蚀疲劳过程及裂纹形成和扩展过程,结合腐蚀疲劳破坏的特点,研究了平行钢丝的腐蚀疲劳寿命评价分阶段计算方法。
[Abstract]:For modern cable-system bridges, cable system is the main load-bearing component. A large number of engineering examples show that in the process of bridge service, under the interaction of cyclic load and corrosion environment, the cable is prone to corrosion fatigue damage. The direct reason is that the corrosion and fatigue of steel wire lead to the decrease of mechanical properties and bearing capacity of cable, which seriously threaten the safety of bridge structure. The research on the bearing capacity and fatigue life of steel wire under rust grading can not only guarantee the high safety of the cable during the bridge operation, but also replace the cable in the appropriate time, and reduce the economic loss. The main purpose of this paper is to extend the service life of bridge structure. The main contents of this paper are summarized as follows: (1) the corrosion characteristics of parallel steel wire are studied, and the process of steel wire corrosion is analyzed. Combined with the results of artificial accelerated steel wire corrosion test, the corrosion degree of steel wire is classified. It provides a basis for the fatigue performance test of steel wire under corrosion classification. (2) the 3D size of steel wire pit is counted, and the distribution characteristics of depth, length and width of the pit are studied. Then the finite element method is used to analyze the stress concentration factors of typical semi-elliptical pits. (3) fatigue tests of steel wires with different corrosion grades are carried out, and the fatigue life S-N curves are obtained. The effect of corrosion degree on fatigue life of steel wire was studied. The corrosion fatigue fracture mechanism of steel wire was studied by combining the results of corrosion fatigue test and SEM picture analysis of steel wire fracture. The stress intensity factor of steel wire with surface crack is studied and the uniform expression of geometric correction coefficient of stress intensity factor of crack propagation under tensile load is obtained. The residual strength of steel wire with surface crack damage is compared and analyzed. (4) the corrosion fatigue process and crack formation and propagation process of cable steel wire are studied and analyzed. The calculation method of corrosion fatigue life of parallel steel wire is studied.
【学位授予单位】：南京林业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U441.4
本文编号：2144771
[Abstract]:For modern cable-system bridges, cable system is the main load-bearing component. A large number of engineering examples show that in the process of bridge service, under the interaction of cyclic load and corrosion environment, the cable is prone to corrosion fatigue damage. The direct reason is that the corrosion and fatigue of steel wire lead to the decrease of mechanical properties and bearing capacity of cable, which seriously threaten the safety of bridge structure. The research on the bearing capacity and fatigue life of steel wire under rust grading can not only guarantee the high safety of the cable during the bridge operation, but also replace the cable in the appropriate time, and reduce the economic loss. The main purpose of this paper is to extend the service life of bridge structure. The main contents of this paper are summarized as follows: (1) the corrosion characteristics of parallel steel wire are studied, and the process of steel wire corrosion is analyzed. Combined with the results of artificial accelerated steel wire corrosion test, the corrosion degree of steel wire is classified. It provides a basis for the fatigue performance test of steel wire under corrosion classification. (2) the 3D size of steel wire pit is counted, and the distribution characteristics of depth, length and width of the pit are studied. Then the finite element method is used to analyze the stress concentration factors of typical semi-elliptical pits. (3) fatigue tests of steel wires with different corrosion grades are carried out, and the fatigue life S-N curves are obtained. The effect of corrosion degree on fatigue life of steel wire was studied. The corrosion fatigue fracture mechanism of steel wire was studied by combining the results of corrosion fatigue test and SEM picture analysis of steel wire fracture. The stress intensity factor of steel wire with surface crack is studied and the uniform expression of geometric correction coefficient of stress intensity factor of crack propagation under tensile load is obtained. The residual strength of steel wire with surface crack damage is compared and analyzed. (4) the corrosion fatigue process and crack formation and propagation process of cable steel wire are studied and analyzed. The calculation method of corrosion fatigue life of parallel steel wire is studied.
【学位授予单位】：南京林业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U441.4
【引证文献】
相关会议论文 前1条
1 盛海军;李少芳;晏国泰;;淇澳大桥换索施工技术[A];全国既有桥梁加固、改造与评价学术会议论文集[C];2008年
，本文编号：2144771
本文链接：https://www.wllwen.com/kejilunwen/daoluqiaoliang/2144771.html
