【摘要】：鋼纖維混凝土（SFRC）是一種復(fù)雜的非均質(zhì)復(fù)合材料，宏觀力學(xué)模型將其視作均質(zhì)材料來研究其力學(xué)性能，并通過一系列試驗(yàn)得出參數(shù)以指導(dǎo)工程實(shí)踐，從某種程度而言，均質(zhì)的簡(jiǎn)化很難描述鋼纖維混凝土材料在外荷載下裂紋形成、發(fā)展及連通的損傷破壞過程。本文將從細(xì)觀層次上將鋼纖維增強(qiáng)混凝土(SFRC)材料看作是由鋼纖維增強(qiáng)體、混凝土基體所組成的非均質(zhì)兩相復(fù)合材料，對(duì)其力學(xué)性能進(jìn)行數(shù)值模擬，模擬時(shí)暫不考慮二者的界面粘結(jié)性能。 抗拉強(qiáng)度和抗壓強(qiáng)度是鋼纖維混凝土材料的基本力學(xué)性能指標(biāo)，是研究復(fù)雜應(yīng)力狀態(tài)的基礎(chǔ)�；炷潦堑湫偷亩嘞鄰�(fù)合材料，摻入鋼纖維之后，強(qiáng)度提高程度不大，但其力學(xué)性能得到改善。和混凝土材料相比，脆性顯著改善，應(yīng)力應(yīng)變曲線有較緩的下降段，不會(huì)出現(xiàn)典型的脆性破壞。本文結(jié)合MATLAB數(shù)學(xué)計(jì)算軟件產(chǎn)生偽隨機(jī)數(shù)的功能與ABAQUS有限元分析軟件的非線性計(jì)算功能，建立不同體積含量的鋼纖維隨機(jī)分布于代表體積單元(Representative Volume Element，RVE)的三維數(shù)值模型，將鋼纖維看作桁架（truss）單元嵌入基體中，不考慮二者的界面粘結(jié)。采用均勻化方法，，首先通過與文獻(xiàn)中試驗(yàn)進(jìn)行對(duì)比，調(diào)試部分參數(shù)，計(jì)算由隨機(jī)分散的鋼纖維、混凝土基體兩相復(fù)合材料的抗壓應(yīng)力應(yīng)變曲線和抗拉應(yīng)力應(yīng)變曲線，以驗(yàn)證細(xì)觀數(shù)值模擬的可行性和準(zhǔn)確性，然后進(jìn)行參數(shù)化分析，考慮隨機(jī)鋼纖維的長(zhǎng)徑比、體積含量變化對(duì)復(fù)合材料力學(xué)行為的影響。 針對(duì)鋼纖維和混凝土基體之間的界面粘結(jié)性能，出于計(jì)算時(shí)間和計(jì)算精度的考慮，分別建立混凝土基體、鋼纖維以及二者粘結(jié)層的二維平面應(yīng)變有限元模型，運(yùn)用基于斷裂力學(xué)的內(nèi)聚力模型，合理設(shè)置參數(shù)，首先與文獻(xiàn)中單根鋼纖維拉拔試驗(yàn)進(jìn)行對(duì)比，驗(yàn)證采用該模型的正確性，進(jìn)而考慮鋼纖維類型、嵌入基體的長(zhǎng)度變化對(duì)界面粘結(jié)性能的影響。
[Abstract]:Steel fiber reinforced concrete (SFRC) is a kind of complex heterogeneous composite material, which is considered as homogeneous material by macroscopic mechanical model to study its mechanical properties, and parameters are obtained through a series of tests to guide engineering practice. Homogenization is difficult to describe the damage and failure process of steel fiber reinforced concrete (SFRC) under external loading. In this paper, the steel fiber reinforced concrete (SFRC) material is regarded as a heterogeneous two-phase composite composed of steel fiber reinforcement and concrete matrix at the mesoscopic level, and its mechanical properties are numerically simulated. The interfacial bond properties of the two are not considered in the simulation. Tensile strength and compressive strength are the basic mechanical properties of steel fiber reinforced concrete (SFRC) and are the basis of studying complex stress state. Concrete is a typical multiphase composite material. After adding steel fiber, the strength of concrete is improved little, but its mechanical properties are improved. Compared with the concrete material, the brittleness is obviously improved, the stress-strain curve has a slow descending section, and there is no typical brittle failure. Combined with the function of generating pseudorandom numbers by MATLAB and the nonlinear calculation of Abaqus finite element analysis software, a three-dimensional numerical model of steel fibers with different volume contents distributed randomly to Representative Volume element (RVE) is established in this paper. The steel fiber is regarded as a truss (truss) element embedded in the matrix without considering the interface bond between them. By using homogenization method, the compressive stress-strain curves and tensile stress-strain curves of randomly dispersed steel fiber and concrete matrix two-phase composites are calculated by comparing with the experiments in literature and adjusting some parameters. In order to verify the feasibility and accuracy of mesoscopic numerical simulation, parameterized analysis was carried out to consider the influence of the aspect ratio and volume content of random steel fiber on the mechanical behavior of composites. According to the interfacial bond behavior between steel fiber and concrete matrix, a two-dimensional plane strain finite element model of concrete matrix, steel fiber and bond layer is established for the consideration of calculation time and accuracy. The cohesive force model based on fracture mechanics is used to reasonably set the parameters. Firstly, compared with the single steel fiber drawing test in literature, the correctness of the model is verified, and the type of steel fiber is considered. The influence of the length of the embedded matrix on the interfacial adhesion.
【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】：2014
【分類號(hào)】：TU528.572

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本文編號(hào)：2118962