交变应力状态下斜拉桥拉索电化学腐蚀疲劳试验研究

发布时间：2018-02-26 10:02

本文关键词： 交变应力斜拉索电化学腐蚀试验腐蚀疲劳　出处：《重庆交通大学》2015年硕士论文　论文类型：学位论文

【摘要】：斜拉桥因为跨越能力大且结构形式简洁美观,已经逐渐成为现代大跨径桥梁的一种重要结构形式,但是斜拉索的腐蚀却制约着斜拉桥的跨度往更大的跨径发展。目前,国内外对斜拉桥拉索腐蚀进行了大量的研究,主要腐蚀研究方法包括:大气环境中对斜拉索完全暴露的自然腐蚀试验和室内对斜拉索的加速腐蚀模拟试验。斜拉索的室内加速腐蚀模拟试验的种类很多,从模拟的环境大致可以分为:盐雾环境下的加速腐蚀模拟试验、酸雨环境下的加速腐蚀模拟试验、电化学环境下的加速腐蚀模拟试验,但是这些加速腐蚀模拟试验主要是在无应力状态下进行的,没有考虑应力对拉索腐蚀的影响。本文主要通过对交变应力状态下斜拉索电化学腐蚀疲劳试验的模拟,来分析交变荷载对斜拉索的腐蚀的影响。通过对镀锌钢绞线在不同的应力状态、不同腐蚀周期的加速腐蚀模拟试验,得出相同腐蚀周期,镀锌钢绞线在交变应力状态下,镀锌钢绞线的腐蚀最快;相同应力状态下,镀锌钢绞线的腐蚀周期越长,腐蚀越严重。然后对斜拉索的在不同应力、不同腐蚀周期状态下的腐蚀状态进行推断,再通过Ansys对斜拉索在静态应力和交变应力状态下的腐蚀状况进行有限元模拟分析,得出交变应力对斜拉索的腐蚀影响情况包括以下几个方面:①同一应力状态下,腐蚀段拉索外层钢绞线的应力值大于内部钢绞线的应力值,而未腐蚀段拉索外层钢绞线的应力值小于内部钢绞线的应力值;说明腐蚀导致拉索截面受力重新分布,外层钢绞线应力值增大。②同一应力状态下,沿着拉索的长度,未腐蚀段截面的应力分布比较稳定没有什么波动,但是在拉索腐蚀段,应力出现了峰值,即应力集中;说明腐蚀导致了腐蚀段拉索的应力集中。③不同应力状态下,交变应力对腐蚀段拉索外层钢绞线的应力值与内部钢绞线的应力值差值的影响更大,沿拉索长度,腐蚀段拉索出现的应力峰值也更大;说明交变应力对拉索腐蚀后,出现的应力分布和局部应力集中影响更大。
[Abstract]:Cable-stayed bridge because of large span capacity and simple structure form appearance, has gradually become an important form of modern long-span bridges, but corrosion cable restricts the cable-stayed bridge to span greater span development. At present, domestic and foreign to the cable corrosion carried out a lot of research on cable-stayed bridge. The main research methods include: Natural corrosion corrosion test and indoor completely exposed to the stay cables in the atmospheric environment on the cable corrosion simulation test. The cable type indoor accelerated corrosion simulation tests of many, from the simulation environment can be roughly divided into: accelerated corrosion simulation test of salt spray environment, accelerated corrosion simulation the test of acid rain environment, accelerated corrosion simulation test of electrochemical environment, but these accelerated corrosion tests are mainly carried out in non stress state, without considering the stress on the cable corrosion Effect. This paper mainly through the simulation of stress state of cable corrosion fatigue test on AC, to analyze the impact of corrosion on alternating load cable. The galvanized steel wire in different stress state, accelerated corrosion simulation test of different corrosion cycle, reached the same corrosion cycle, galvanized steel strand in alternating stress under the condition of corrosion of galvanized steel wire for the fastest; the same stress condition, the corrosion of galvanized steel wire cycle is long, the more serious corrosion. Then the cable stress in different corrosion state of different corrosion cycle conditions are deduced, and then through the Ansys of cable stress and alternating stress corrosion the status of the state of the finite element analysis on the static, the alternating stress corrosion influence force of cables include the following several aspects: the same stress condition, the corrosion of the outer steel strand cable The stress value is greater than the internal stress of steel strand, and the corrosion of steel strand cable outer stress value is less than the internal stress of steel strand; corrosion cause redistribution of stress that cable section, the outer layer of steel strand stress increases at the same stress condition, along the length of cable distribution. Stress corrosion section is relatively stable and not what fluctuations, but in the cable corrosion stress, peak value, the stress concentration; indicating that the corrosion resulted in stress concentration. The corrosion of cables under different stress conditions, alternating stress corrosion of steel strand cable outer segment value the internal strand stress difference is more influential along the cable length, the peak stress corrosion section of cable also more; that alternating stress of cable corrosion, the stress distribution and stress concentration of a greater impact.

【学位授予单位】：重庆交通大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U446

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