【摘要】：混凝土作為一種典型的多相非均質(zhì)復(fù)合材料,在土木工程領(lǐng)域有著非常廣泛的應(yīng)用,其材料性能與混凝土結(jié)構(gòu)的耐久性和安全性等有著密切的聯(lián)系�；炷羶�(nèi)部各相材料的力學(xué)性能差距很大,加之微裂紋、孔隙和其它初始缺陷的存在導(dǎo)致混凝土的基本性能變化規(guī)律有待進(jìn)一步研究。數(shù)值分析方法作為研究混凝土劣化機(jī)理的重要手段,可以在各項(xiàng)試驗(yàn)數(shù)據(jù)和理論研究的支持下對混凝土的各項(xiàng)力學(xué)性能進(jìn)行模擬和預(yù)測,是當(dāng)下混凝土材料性能研究的熱點(diǎn)之一。混凝土在細(xì)觀層次上可以看作是由粗細(xì)骨料、水泥漿體和各種初始缺陷點(diǎn)等組成的復(fù)合材料。基于細(xì)觀分析方法的混凝土數(shù)值模型,在參數(shù)選擇合理的情況下不僅可以直觀的反映出混凝土各相組成對其性能的影響以及持續(xù)變化荷載作用下的整個(gè)損傷斷裂過程,而且可以避免實(shí)體試驗(yàn)中環(huán)境因素和人為失誤等客觀原因?qū)υ囼?yàn)結(jié)果的影響。本文基于混凝土細(xì)觀隨機(jī)骨料模型,將損傷力學(xué)理論應(yīng)用到數(shù)值分析中,模擬研究了混凝土試件在單軸荷載作用下的的損傷破壞過程,并在數(shù)值模型的建立過程中引入等效化方法的概念,通過等效前后模擬結(jié)果的對比驗(yàn)證了等效化方法在混凝土的細(xì)觀損傷模型中應(yīng)用的合理性。具體工作如下:1.闡述了等效化方法及混凝土損傷斷裂力學(xué)的基本概念,并研究了等效化方法在混凝土細(xì)觀力學(xué)分析中的具體應(yīng)用。2.在數(shù)值軟件中運(yùn)用蒙特卡洛方法,通過編寫程序化語言實(shí)現(xiàn)了圓形骨料顆粒在指定的區(qū)域和骨料級配范圍內(nèi)的隨機(jī)分布。然后對生成的骨料坐標(biāo)數(shù)據(jù)進(jìn)行處理,添加界面單元最終生成二維混凝土試件的幾何模型。3.對有限元軟件進(jìn)行二次開發(fā),將雙折線損傷模型引入到混凝土試件的單軸受拉、單軸受壓的數(shù)值模擬中去,通過設(shè)置狀態(tài)變量判斷單元是否失效刪除,進(jìn)而模擬出混凝土內(nèi)部裂紋的擴(kuò)展規(guī)律,并得到相應(yīng)的應(yīng)力應(yīng)變曲線。4.將等效化方法應(yīng)用到數(shù)值模型中去,即把砂漿基質(zhì)與界面過渡區(qū)等效為一種材料,通過與原三相材料模型的試驗(yàn)結(jié)果進(jìn)行對比,驗(yàn)證方法的可靠性,并在子程序中創(chuàng)建損傷變量輸出模塊,較為直觀地反映等效后模型的損傷斷裂過程。5.討論了混凝土的界面厚度、骨料粒徑選取范圍和孔隙率對其性能的影響。本文運(yùn)用等效化方法簡化了模型的建立過程,而且開發(fā)出了模型的損傷變量輸出模塊,在提高模型計(jì)算效率的同時(shí)可以更真實(shí)和直觀地表達(dá)混凝土在單軸荷載作用下的損傷斷裂過程。為進(jìn)行混凝土基本性能的細(xì)觀分析提供技術(shù)支持,為對混凝土結(jié)構(gòu)進(jìn)行結(jié)構(gòu)分析與優(yōu)化設(shè)計(jì)奠定理論基礎(chǔ)。
[Abstract]:As a typical heterogeneous heterogeneous composite, concrete is widely used in the field of civil engineering. The properties of concrete are closely related to the durability and safety of concrete structures. The mechanical properties of various phases in concrete are very wide, and the existence of micro cracks, pores and other initial defects is guided. The basic performance changes of concrete need to be further studied. As an important means to study the deterioration mechanism of concrete, numerical analysis method can be used to simulate and predict the mechanical properties of concrete under the support of experimental data and theoretical research. It is one of the hot spots in the study of the performance of the concrete. At the meso level, it can be seen as a composite material consisting of coarse aggregate, cement paste and various initial defect points. The numerical model of concrete based on the meso analysis method can not only directly reflect the effect of each phase composition of concrete on its performance and the continuous changing load under the reasonable selection of parameters. In this paper, the damage mechanics theory is applied to the numerical analysis, and the damage and damage process of the concrete specimen under uniaxial load is simulated and studied. The concept of equivalent method is introduced in the process of establishing the numerical model, and the rationality of the application of the equivalent method in the meso damage model of concrete is verified through the comparison of the equivalent simulation results before and after the equivalent simulation. The concrete work is as follows: 1. the equivalent method and the basic concepts of the damage fracture mechanics of concrete are expounded, and the equivalence is studied. The concrete application of method in the analysis of concrete meso mechanics.2. uses Monte Carlo method in the numerical software. Through programming language, the random distribution of circular aggregate particles in the specified area and aggregate gradation is realized. Then the generated aggregate coordinate data are processed and the interface unit is added to the final generation. The geometric model.3. of concrete specimen is developed two times for the finite element software, and the double line damage model is introduced to the single axis tension of the concrete specimen and the numerical simulation of the single axis compression. By setting the state variable to judge whether the unit is invalid and deleted, then the law of the expansion of the concrete internal crack is simulated and the corresponding stress is obtained. The strain curve.4. applies the equivalent method to the numerical model, that is, the mortar matrix and the interface transition zone are equivalent to a kind of material. By comparing with the experimental results of the original three phase material model, the reliability of the method is verified and the damage variable output die block is created in the subprogram, which is more intuitively reflected the damage fracture of the equivalent model. The cracking process.5. discusses the interface thickness of concrete, the selection range of aggregate size and the effect of porosity on its performance. In this paper, the establishment process of the model is simplified by using the equivalent method, and the damage variable output module of the model is developed. The concrete can be more truly and intuitively expressed in the same time as the model calculation efficiency is raised. The damage and fracture process under the axial load provides a technical support for the meso analysis of the basic properties of concrete, which lays a theoretical foundation for the structural analysis and optimization of the concrete structure.
【學(xué)位授予單位】：河南工業(yè)大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：TU528

【參考文獻(xiàn)】

相關(guān)期刊論文 前10條

1 程書懷;任志剛;李培鵬;上官瑾瑜;;基于LS-DYNA的混凝土三維隨機(jī)凹凸型骨料數(shù)值建模[J];武漢理工大學(xué)學(xué)報(bào);2014年12期

2 武亮;王菁;糜凱華;何修偉;武世倩;;一種生成橢球形骨料的混凝土細(xì)觀模型方法[J];混凝土;2014年11期

3 于孝民;任青文;;凍融循環(huán)作用下普通混凝土斷裂能試驗(yàn)[J];河海大學(xué)學(xué)報(bào)(自然科學(xué)版);2010年01期

4 曲曉東;丁鑄;宋玉普;;復(fù)雜應(yīng)力下大骨料混凝土與二級配混凝土強(qiáng)度對比試驗(yàn)研究[J];大連理工大學(xué)學(xué)報(bào);2009年06期

5 趙吉坤;;混凝土四相復(fù)合模型的三維細(xì)觀破壞模擬[J];土木建筑與環(huán)境工程;2009年04期

6 田佳琳;李慶斌;;混凝土Ⅰ型裂縫的靜力斷裂損傷耦合分析[J];水利學(xué)報(bào);2007年02期

7 陳惠蘇;孫偉;STROEVEN Piet;;水泥基復(fù)合材料界面過渡區(qū)體積分?jǐn)?shù)的定量計(jì)算[J];復(fù)合材料學(xué)報(bào);2006年02期

8 張子明,趙吉坤,吳昊,姚朋士;混凝土單軸荷載下細(xì)觀損傷破壞的數(shù)值模擬[J];河海大學(xué)學(xué)報(bào)(自然科學(xué)版);2005年04期

9 張子明,趙吉坤,倪志強(qiáng);混凝土拉伸斷裂的細(xì)觀力學(xué)模擬[J];河海大學(xué)學(xué)報(bào)(自然科學(xué)版);2005年03期

10 鄭建軍,周欣竹,姜璐;混凝土楊氏模量預(yù)測的三相復(fù)合球模型[J];復(fù)合材料學(xué)報(bào);2005年01期

相關(guān)博士學(xué)位論文 前1條

1 金瀏;細(xì)觀混凝土分析模型與方法研究[D];北京工業(yè)大學(xué);2014年

相關(guān)碩士學(xué)位論文 前4條

1 蔣寶庫;再生混凝土細(xì)觀力學(xué)及氯離子擴(kuò)散數(shù)值模擬[D];濟(jì)南大學(xué);2015年

2 龔正爐;基于隨機(jī)骨料模型的混凝土性能多尺度數(shù)值模擬研究[D];浙江大學(xué);2013年

3 鄭麗華;考慮細(xì)觀的水泥混凝土養(yǎng)生變異性研究[D];長安大學(xué);2010年

4 曹慶堅(jiān);基于網(wǎng)格模型的混凝土細(xì)觀結(jié)構(gòu)數(shù)值模擬[D];大連理工大學(xué);2006年

，

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