本文關(guān)鍵詞： 混凝土粗糙接觸界面 W-M函數(shù)法 微凸體 剪切力 摩擦因子　出處：《華南理工大學(xué)》2015年碩士論文　論文類(lèi)型：學(xué)位論文

【摘要】：通常情況下,混凝土構(gòu)件產(chǎn)生裂縫后會(huì)沿最不利位置開(kāi)展,混凝土構(gòu)件產(chǎn)生裂縫后并非完全不能繼續(xù)承受荷載,開(kāi)展裂縫的兩側(cè)接觸面因其表面是粗糙和不規(guī)則的,能夠產(chǎn)生一定大小的摩擦力�；炷林g的滑動(dòng)能形成剪切力的傳遞,它與抗剪鋼筋共同作用抵抗荷載。至于混凝土構(gòu)件開(kāi)裂后,剪切力到底能傳遞多少?剪力傳遞的系數(shù)有沒(méi)有固定的數(shù)理統(tǒng)計(jì)規(guī)律?現(xiàn)行研究還尚無(wú)確切數(shù)值。本文對(duì)此提出了混凝土開(kāi)裂面的力學(xué)行為分析命題,旨在解決兩配的混凝土開(kāi)裂后粗糙接觸界面的力學(xué)行為,從而為混凝土構(gòu)件裂縫開(kāi)展區(qū)域的剪切力計(jì)算提供一定的力學(xué)理論基礎(chǔ)。本文以接觸力學(xué)為理論基礎(chǔ),通過(guò)比較分析發(fā)現(xiàn)混凝土開(kāi)裂后的粗糙輪廓表現(xiàn)出的自仿射相似性特征與分形接觸模型相吻合,因此可以運(yùn)用分形學(xué)理論研究混凝土粗糙接觸界面。本文通過(guò)采用分形學(xué)理論里的修正中點(diǎn)位移法和W-M函數(shù)法分別生成了混凝土粗糙接觸的界面,再根據(jù)G-W模型對(duì)其界面進(jìn)行簡(jiǎn)化。然后借助非線性有限元軟件ABAQUS,建立以混凝土材料為分析對(duì)象的接觸模型,對(duì)其進(jìn)行數(shù)值分析。本文接觸模型采用了“球帽”形的微凸體接觸對(duì)。文中首先分析了一對(duì)微凸體接觸對(duì)的接觸壓力與接觸面積關(guān)系,得到了非線性關(guān)系曲線。然后給出了接觸壓力-接觸面積關(guān)系曲線圖和接觸壓力-位移關(guān)系曲線圖,和Hertz理論預(yù)算結(jié)果進(jìn)行對(duì)比,發(fā)現(xiàn)本文預(yù)算結(jié)果與Hertz理論結(jié)果非常接近,從而驗(yàn)證了模型的正確性。為了驗(yàn)證表面粗糙形貌對(duì)接觸面積的影響,在模型里采用不同摩擦系數(shù)試算,最后發(fā)現(xiàn)單個(gè)微凸體里的摩擦因子對(duì)接觸面積影響并不大。為了進(jìn)一步驗(yàn)證微凸體接觸對(duì)的力學(xué)行為特性,本文擴(kuò)大了接觸模型。將一對(duì)微凸體接觸對(duì)擴(kuò)展到了七對(duì)接觸對(duì),14個(gè)球帽高度按修正的指數(shù)分布擬合高斯分布。通過(guò)ABAQUS分析計(jì)算后,得到了擴(kuò)大后接觸壓力與接觸面積關(guān)系,結(jié)果表明考慮了多個(gè)接觸對(duì)后的接觸壓力與接觸面積關(guān)系呈線性關(guān)系,多個(gè)接觸對(duì)之間互相關(guān),多個(gè)微凸體接觸對(duì)所產(chǎn)生的摩擦因子是穩(wěn)定的。切向力與豎向力的比值系數(shù)符合線性遞減規(guī)律,與W-M模型理論相吻合。
[Abstract]:In general, concrete members will develop along the most unfavorable position after cracks, and concrete members will not be completely unable to bear the load after cracks. The contact surfaces on both sides of the cracks are rough and irregular because their surfaces are rough and irregular. Can produce a certain size of friction. The slip between the concrete can form shear force transmission, it and shear reinforcement act together to resist the load. As for concrete members after cracking, how much shear force can be transferred? Is there a fixed mathematical statistical rule for the coefficient of shear transfer? In this paper, a proposition of mechanical behavior analysis of concrete cracking surface is put forward, which aims at solving the mechanical behavior of rough contact interface after cracking of two concrete. This provides a certain theoretical basis for the calculation of shear force in the crack area of concrete members. This paper takes contact mechanics as the theoretical basis. Through the comparative analysis, it is found that the self-affine similarity of the cracked rough contour is consistent with the fractal contact model. Therefore, the fractal theory can be used to study the rough contact interface of concrete. In this paper, the interface of rough contact of concrete is generated by using the modified midpoint displacement method and W-M function method in fractal theory. Then the interface is simplified according to the G-W model, and then the contact model of concrete material is established with the help of the nonlinear finite element software Abaqus. In this paper, a "ball cap" contact pair of microconvex body is used in the contact model. The relation between contact pressure and contact area of a pair of microconvex contact pairs is first analyzed in this paper. The nonlinear relation curve is obtained, and the curves of contact pressure-contact area relation and contact pressure-displacement relationship are given, and compared with the results of Hertz theory, it is found that the results of this paper are very close to those of Hertz theory. In order to verify the effect of rough surface topography on contact area, different friction coefficients were used in the model. Finally, it is found that the friction factor in a single microconvex body has little effect on the contact area. In this paper, the contact model is expanded. The contact pair of a pair of microconvex bodies is extended to seven pairs of contact pairs, and 14 spherical cap heights fit the Gao Si distribution according to the modified exponential distribution. The relationship between the expanded contact pressure and the contact area is obtained by ABAQUS analysis and calculation. The results show that the relationship between the contact pressure and the contact area is linear, and the relationship between the contact pressure and the contact area is correlated with each other. The ratio coefficient of tangential force to vertical force is in accordance with the law of linear decline, which is consistent with the theory of W-M model.
【學(xué)位授予單位】：華南理工大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類(lèi)號(hào)】：TU528

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