發(fā)布時間：2018-05-09 22:12

  本文選題：玻璃纖維混凝土 + 彎曲疲勞��； 參考：《昆明理工大學(xué)》2013年博士論文

【摘要】：玻璃纖維混凝土(Glass Fiber Reinforced Concrete,簡稱為GFRC)作為一種新型混凝土材料,由于玻璃纖維的加入,改善了混凝土基體的脆性,提高了抗拉、抗彎、抗沖擊及韌性等性能。若將GFRC用于工程實際中可以很好的改善結(jié)構(gòu)和構(gòu)件的耐疲勞性能。在工程實際中應(yīng)用得較多、理論研究較為成熟的是鋼纖維混凝土,其它纖維混凝土材料的研究還不普遍。玻璃纖維具有優(yōu)越的物理力學(xué)性能,隨著玻璃纖維在混凝土工程運用領(lǐng)域的不斷擴大,相關(guān)理論研究顯得尤為重要�；炷�土類材料在循環(huán)荷載作用下的疲勞強度和變形性能是研究混凝土結(jié)構(gòu)疲勞性能和疲勞強度的基礎(chǔ)。為了給GFRC結(jié)構(gòu)的合理設(shè)計和正確分析提供重要的試驗依據(jù)和理論研究參考,論文進(jìn)行了GFRC彎曲疲勞性能及累積損傷研究,主要試驗與理論研究工作包括以下幾方面： 1、進(jìn)行了0%、0.6%、0.8%和1%四種纖維率GFRC試件的靜載試驗和等幅循環(huán)荷載試驗,研究了玻璃纖維對GFRC各項力學(xué)性能(如抗拉強度、抗壓強度、抗折強度及抗折彈性模量等)的影響,測量了循環(huán)加載下試件的疲勞壽命、應(yīng)變；對試驗結(jié)果進(jìn)行分析,得到了GFRC疲勞應(yīng)變、疲勞彈性模量和循環(huán)應(yīng)力應(yīng)變曲線的發(fā)展規(guī)律及相應(yīng)經(jīng)驗公式。 2、應(yīng)用統(tǒng)計學(xué)理論對GFRC的疲勞壽命進(jìn)行分析,證明了GFRC的疲勞壽命服從兩參數(shù)、三參數(shù)的Weibull分布,其中三參數(shù)Weibull分布更適宜用來描述GFRC彎曲疲勞壽命的分布規(guī)律；給出了可用于確定等幅彎曲荷載下GFRC疲勞壽命的S-N曲線、考慮存活率的P-S-N曲線方程。通過方程得到了GFRC的疲勞強度,并與普通混凝土、鋼纖維混凝土進(jìn)行比較,結(jié)果說明了GFRC有優(yōu)越的抗疲勞性能。 3、根據(jù)GFRC疲勞應(yīng)變和變形模量隨循環(huán)次數(shù)的發(fā)展規(guī)律,提出了GFRC彎曲疲勞破壞準(zhǔn)則的應(yīng)變衡量和彈模衡量方法。結(jié)合斷裂分析中的能量平衡和耗散原理,探討了GFRC的疲勞內(nèi)部損傷機理,從而合理地解釋了研究獲得的疲勞變形規(guī)律。 4、從連續(xù)介質(zhì)損傷力學(xué)、Miner線性累積損傷理論和能量釋放理論出發(fā),分別選用由殘余塑性應(yīng)變、最大疲勞應(yīng)變和循環(huán)滯回能表示的損傷變量研究了GFRC的疲勞損傷累積規(guī)律,并結(jié)合疲勞試驗結(jié)果確定了模型參數(shù),得到了相應(yīng)的損傷累積方程。 5、運用灰色系統(tǒng)預(yù)測理論,在疲勞試驗結(jié)果的基礎(chǔ)上得到了GFRC疲勞強度預(yù)測的灰色GM(1,1)模型。在此基礎(chǔ)上提出一個模型參數(shù)可通過S-N曲線確定,便于工程應(yīng)用的強度衰減模型,此模型可用于單級循環(huán)荷載下GFRC的疲勞壽命估算。以上研究都通過預(yù)測值與試驗值的比較證明了方法的可行性。
[Abstract]:As a new type of concrete material, glass Fiber Reinforced Concrete, (glass) can improve the brittleness of concrete matrix and improve its tensile, flexural, impact and toughness properties. If GFRC is used in engineering practice, the fatigue resistance of structures and components can be improved. Steel fiber reinforced concrete (SFRC) is widely used in engineering practice, and other fiber reinforced concrete materials are not widely studied. Glass fiber has excellent physical and mechanical properties. With the continuous expansion of glass fiber in the field of concrete engineering application, the related theoretical research is particularly important. The fatigue strength and deformation behavior of concrete materials under cyclic loading are the basis of studying the fatigue performance and fatigue strength of concrete structures. In order to provide important experimental basis and theoretical reference for the reasonable design and correct analysis of GFRC structures, the bending fatigue performance and cumulative damage of GFRC are studied in this paper. The main experimental and theoretical research work includes the following aspects: 1. Static load tests and cyclic loading tests were carried out on 0 / 0. 6% and 1% fiber GFRC specimens. The effects of glass fiber on the mechanical properties of GFRC (such as tensile strength, compressive strength, flexural strength and flexural modulus) were studied. The fatigue life and strain of specimens under cyclic loading were measured, and the experimental results were analyzed, and the development law and corresponding empirical formula of fatigue strain, fatigue modulus of elasticity and cyclic stress-strain curve of GFRC were obtained. 2. The fatigue life of GFRC is analyzed by statistical theory, and it is proved that the fatigue life of GFRC is from the Weibull distribution of two parameters and three parameters, and the three-parameter Weibull distribution is more suitable to describe the distribution law of GFRC bending fatigue life; The S-N curve which can be used to determine the fatigue life of GFRC under constant amplitude bending load is given. The P-S-N curve equation considering the survival rate is given. The fatigue strength of GFRC is obtained by the equation and compared with ordinary concrete and steel fiber reinforced concrete. The results show that GFRC has superior fatigue resistance. 3. According to the development rule of GFRC fatigue strain and deformation modulus with cyclic times, the strain and elastic modulus measurement methods of GFRC flexural fatigue failure criterion are proposed. Combined with the principle of energy balance and dissipation in fracture analysis, the internal damage mechanism of fatigue of GFRC is discussed, and the fatigue deformation law obtained by the study is explained reasonably. 4. Based on Miner's linear cumulative damage theory and energy release theory in continuum damage mechanics, the fatigue damage accumulation law of GFRC is studied by selecting the damage variables expressed by residual plastic strain, maximum fatigue strain and cyclic hysteresis energy, respectively. According to the fatigue test results, the model parameters are determined and the corresponding damage accumulation equation is obtained. 5. Based on the results of fatigue tests, the grey GM-1) model for fatigue strength prediction of GFRC is obtained by using the theory of grey system prediction. On this basis, a model parameter can be determined by S-N curve, which is convenient for engineering application. The model can be used to estimate the fatigue life of GFRC under single-stage cyclic load. The feasibility of the method is proved by comparing the predicted value with the experimental value.
【學(xué)位授予單位】：昆明理工大學(xué)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2013
【分類號】：TU528.572

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