本文關(guān)鍵詞：基于細(xì)觀力學(xué)方法的混凝土多尺度損傷力學(xué)行為研究　出處：《大連理工大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

  更多相關(guān)文章： 混凝土 Mori-Tanaka方法 等效彈性模量 孔隙率 損傷本構(gòu)

【摘要】：目前混凝土結(jié)構(gòu)是世界上應(yīng)用最廣泛的建筑結(jié)構(gòu)之一,其中混凝土是重要的建筑材料,混凝土結(jié)構(gòu)的破壞實(shí)際上是混凝土材料損傷積累的結(jié)果�；炷潦怯伤�、水泥、粗細(xì)骨料、孔隙及裂紋等組成的復(fù)合材料,混凝土在使用時(shí)隨著外界荷載的增大或者環(huán)境溫度的變化,其內(nèi)部大量存在的微裂紋和微孔洞逐漸延伸、擴(kuò)展直至貫通,使得混凝土材料損傷不斷積累,承載力逐漸降低直至完全喪失,進(jìn)而結(jié)構(gòu)主體喪失承載力,引起混凝土結(jié)構(gòu)的破壞,嚴(yán)重威脅到人身安全和財(cái)產(chǎn)安全�；诨炷恋牧W(xué)性質(zhì),本文主要研究混凝土材料細(xì)觀到宏觀損傷力學(xué)行為。在細(xì)觀層次上混凝土視為是由粗骨料、水泥砂漿及兩者之間的界面過(guò)渡區(qū)組成的三相非勻質(zhì)復(fù)合材料,首先對(duì)混凝土靜態(tài)力學(xué)性能進(jìn)行研究,采用Mori-Tanaka細(xì)觀力學(xué)理論分析方法,建立三相介質(zhì)力學(xué)特性與混凝土等效彈性模量之間的數(shù)值關(guān)系,分析細(xì)觀各因素對(duì)混凝土等效力學(xué)特性的影響。在砂漿和界面過(guò)渡區(qū)中引入大量隨機(jī)分布的微孔隙,研究微缺陷對(duì)混凝土等效彈性模量的影響,定義混凝土的初始損傷,著眼于細(xì)觀尺度上微裂紋萌生、延伸及貫通等整個(gè)損傷過(guò)程的物理形態(tài)演化,建立孔隙率與混凝土損傷變量的數(shù)值關(guān)系。在混凝土等效彈性模量的時(shí)變特性的研究下,進(jìn)一步探討三相介質(zhì)和混凝土等效損傷模型的建立�；炷脸休d的應(yīng)力應(yīng)變并非三相介質(zhì)承載的應(yīng)力應(yīng)變簡(jiǎn)單加和,對(duì)Mori-Tanaka理論公式推導(dǎo),建立三相介質(zhì)應(yīng)力應(yīng)變場(chǎng)間,及和混凝土應(yīng)力應(yīng)變場(chǎng)的數(shù)值關(guān)系,并對(duì)本文提出的方法與Voigt并聯(lián)模型進(jìn)行算例對(duì)比分析,以三相介質(zhì)的簡(jiǎn)單損傷本構(gòu)模型建立混凝土復(fù)雜的損傷本構(gòu)模型,研究混凝土多尺度損傷力學(xué)行為。
[Abstract]:At present, concrete structure is one of the most widely used building structures in the world, in which concrete is an important building material, the damage of concrete structure is actually the result of concrete material damage accumulation. Cement, coarse aggregate, pore and crack composite materials, concrete in use with the increase of external load or environmental temperature changes, a large number of internal microcracks and micropores gradually extend. The damage of concrete material is accumulated and the bearing capacity is gradually reduced until it is completely lost, and then the main body of the structure loses its bearing capacity, which causes the destruction of concrete structure. Based on the mechanical properties of concrete, this paper mainly studies the macroscopic damage mechanical behavior of concrete materials. In the meso level, concrete is regarded as coarse aggregate. In this paper, the static mechanical properties of cement mortar and its interfacial transition zone are studied, and the Mori-Tanaka method is used to analyze the static mechanical properties of concrete. The numerical relationship between the mechanical properties of three-phase medium and the equivalent elastic modulus of concrete is established. The influence of various factors on the equivalent mechanical properties of concrete is analyzed. A large number of randomly distributed micropores are introduced into the mortar and interfacial transition zone to study the effect of microdefects on the equivalent elastic modulus of concrete. The initial damage of concrete is defined, focusing on the physical morphology evolution of the whole damage process, such as the initiation, extension and penetration of microcracks on a meso-scale. The numerical relationship between porosity and concrete damage variables is established, and the time-varying characteristics of the equivalent elastic modulus of concrete are studied. This paper further discusses the establishment of equivalent damage model of three-phase medium and concrete. The stress-strain of concrete is not the simple sum of stress and strain of three-phase medium. The theoretical formula of Mori-Tanaka is deduced. The numerical relationship between the stress and strain fields of three-phase medium and concrete is established, and the method proposed in this paper is compared with the Voigt parallel model. Based on the simple damage constitutive model of three-phase medium, the complex damage constitutive model of concrete is established, and the multi-scale damage mechanics behavior of concrete is studied.
【學(xué)位授予單位】：大連理工大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：TU528

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