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  本文關(guān)鍵詞：銹蝕鋼筋疲勞斷裂性能研究　出處：《中南大學》2014年碩士論文　論文類型：學位論文

  更多相關(guān)文章： 銹蝕鋼筋 點蝕 裂紋擴展門檻值 試驗 斷口分析 疲勞壽命

【摘要】：在有害介質(zhì)侵蝕環(huán)境下鋼筋混凝土構(gòu)件的疲勞性能,是研究工程結(jié)構(gòu)耐久性問題的一個重要方面。在銹蝕與疲勞復合作用下,鋼筋混凝土構(gòu)件的破壞往往是銹蝕鋼筋的疲勞斷裂。 本文基于裸露鋼筋的腐蝕試驗和鋼筋銹蝕后靜力拉伸與疲勞試驗,探討鋼筋的點蝕演化規(guī)律及銹蝕后的力學性能變化規(guī)律,分析銹蝕對鋼筋疲勞壽命的影響。主要研究工作如下： (1)對鋼筋試件進行了自然銹蝕試驗,試驗結(jié)果表明：鋼筋的蝕坑形貌由為窄而深的半橢球體漸漸發(fā)展為淺而寬的長橢球體,個別蝕坑可發(fā)展為淺寬的凹槽體。 (2)對銹蝕后構(gòu)件進行了靜力拉伸、疲勞拉伸試驗及斷口分析。對于銹蝕鋼筋,其靜力性能發(fā)生了退化且銹蝕對疲勞壽命有顯著的降低作用；靜力拉伸斷口可分為正斷和切斷,疲勞拉伸斷口可分為疲勞源區(qū)、疲勞裂紋擴展區(qū)和瞬時斷裂區(qū),疲勞裂紋萌生于試樣近表面的材料蝕坑根部,并呈扇形向四周擴展。 (3)通過腐蝕后裂尖的應力場分析得到銹蝕鋼筋疲勞裂紋擴展門檻值變化規(guī)律,結(jié)合混凝土中鋼筋的點蝕演變規(guī)律,定量分析了混凝土中鋼筋的疲勞裂紋擴展門檻值。 (4)依據(jù)Paris公式推導出銹蝕鋼筋疲勞壽命模型,對銹蝕鋼筋疲勞試驗進行實例計算,計算結(jié)果表明：鋼筋疲勞壽命對材料的斷裂韌性并不敏感,其值主要取決于裂紋擴展前的初始長度與形狀參數(shù)�；阡P蝕鋼筋的疲勞試驗,提出侵蝕環(huán)境下鋼筋混凝土結(jié)構(gòu)疲勞壽命的預測模式。圖45幅,表17個,參考文獻77篇
[Abstract]:The fatigue performance of reinforced concrete members under the corrosive environment of harmful medium is an important aspect of studying the durability of engineering structures . Under the action of rust and fatigue , the damage of reinforced concrete members is often the fatigue fracture of corroded steel bars . Based on the corrosion test of bare steel bar and the static tension and fatigue test after reinforcement corrosion , the law of pitting evolution and the change law of mechanical properties after corrosion are discussed . The influence of rust on fatigue life of steel bars is analyzed . The main research work is as follows : ( 1 ) The test of natural corrosion on the reinforced concrete specimens is carried out . The test results show that the shape of the corrosion pits of the steel bars is gradually developed into a shallow and broad - long ellipsoid with a narrow and deep semi - ellipsoidal body , and the individual etching pits can be developed into shallow groove bodies . ( 2 ) Static tension , fatigue tensile test and fracture analysis are carried out on the corrosion - resistant members . The static properties of the corroded steel bars are degraded and the corrosion has a significant reduction in fatigue life . The static tensile fracture can be divided into the fatigue source region , the fatigue crack propagation region and the transient fault zone , and the fatigue crack is formed on the root of the material etching pit near the sample near surface , and is expanded in a fan shape . ( 3 ) The change law of fatigue crack propagation threshold value of corroded steel bar is analyzed by the stress field analysis of the back crack tip , and the fatigue crack propagation threshold value of the steel bar in the concrete is quantitatively analyzed in combination with the law of the point erosion evolution of the steel bar in the concrete . ( 4 ) According to Paris formula , the fatigue life model of corroded steel bars is deduced , and the fatigue test of corroded steel bars is calculated . The results show that the fatigue life of steel bars is not sensitive to the fracture toughness of the material .

【學位授予單位】：中南大學
【學位級別】：碩士
【學位授予年份】：2014
【分類號】：TU375

【參考文獻】

相關(guān)期刊論文 前1條

1 沈德建,吳勝興;海水浪濺下混凝土中銹蝕鋼筋性能試驗研究及仿真分析[J];工業(yè)建筑;2005年03期

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本文編號：1425283