發(fā)布時(shí)間：2018-07-25 18:59

【摘要】：對(duì)于現(xiàn)代纜索體系橋梁來(lái)說(shuō),纜索系統(tǒng)是其主要承重構(gòu)件。大量工程實(shí)例表明,橋梁服役過(guò)程中,在循環(huán)荷載和腐蝕環(huán)境的協(xié)同交互作用下,拉索極易發(fā)生腐蝕疲勞損傷破壞,直接原因就是鋼絲的腐蝕或腐蝕疲勞導(dǎo)致了拉索的力學(xué)性能和承載能力的下降,嚴(yán)重威脅著橋梁結(jié)構(gòu)的安全性。對(duì)銹蝕分級(jí)下鋼絲的承載能力和疲勞壽命進(jìn)行深入研究,既能保證拉索在橋梁運(yùn)營(yíng)期間具有較高的安全性,又能在合適的時(shí)間內(nèi)進(jìn)行拉索的更換,減少經(jīng)濟(jì)損失,延長(zhǎng)橋梁結(jié)構(gòu)的使用壽命,這是本文研究的主要目的。本文主要研究?jī)?nèi)容概括如下:(1)研究了拉索平行鋼絲的銹蝕特性,分析了拉索鋼絲銹蝕的過(guò)程,結(jié)合人工加速鋼絲銹蝕試驗(yàn)后的結(jié)果,對(duì)鋼絲銹蝕程度進(jìn)行分級(jí),為開(kāi)展銹蝕分級(jí)下鋼絲的疲勞性能試驗(yàn)研究提供基礎(chǔ)。(2)統(tǒng)計(jì)了鋼絲蝕坑的三維尺寸,研究蝕坑的深度、長(zhǎng)度和寬度3個(gè)參數(shù)的分布特征;然后用有限元方法對(duì)典型半橢圓形蝕坑的應(yīng)力集中系數(shù)進(jìn)行了系統(tǒng)的數(shù)值分析。(3)對(duì)不同銹蝕等級(jí)的鋼絲進(jìn)行了疲勞試驗(yàn),得出疲勞壽命S-N曲線,研究了銹蝕程度對(duì)鋼絲疲勞壽命的影響。結(jié)合腐蝕疲勞試驗(yàn)的結(jié)果和鋼絲斷口的掃描電鏡圖片分析,研究了鋼絲的腐蝕疲勞斷裂機(jī)理。研究帶有表面裂紋鋼絲的應(yīng)力強(qiáng)度因子,得到了拉伸荷載下裂紋擴(kuò)展應(yīng)力強(qiáng)度因子幾何修正系數(shù)的統(tǒng)一表達(dá)式。研究比較分析了帶有表面裂紋損傷的鋼絲剩余強(qiáng)度。(4)研究分析拉索鋼絲腐蝕疲勞過(guò)程及裂紋形成和擴(kuò)展過(guò)程,結(jié)合腐蝕疲勞破壞的特點(diǎn),研究了平行鋼絲的腐蝕疲勞壽命評(píng)價(jià)分階段計(jì)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.
【學(xué)位授予單位】：南京林業(yè)大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：U441.4

【引證文獻(xiàn)】

相關(guān)會(huì)議論文 前1條

1 盛海軍;李少芳;晏國(guó)泰;;淇澳大橋換索施工技術(shù)[A];全國(guó)既有橋梁加固、改造與評(píng)價(jià)學(xué)術(shù)會(huì)議論文集[C];2008年

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本文編號(hào)：2144771