本文選題：混凝土 + 多孔介質(zhì)��； 參考：《安徽工業(yè)大學(xué)》2014年碩士論文

【摘要】：混凝土的體積穩(wěn)定性也是影響混凝土材料及結(jié)構(gòu)耐久性的主要原因，混凝土變形開裂后滲透性增加而使碳化、化學(xué)侵蝕、鋼筋銹蝕等耐久性劣化過程更易進(jìn)行，，嚴(yán)重危害混凝土耐久性及結(jié)構(gòu)使用壽命。實(shí)際工程結(jié)構(gòu)混凝土的變形開裂是環(huán)境溫濕度變化和結(jié)構(gòu)外荷載共同作用的結(jié)果，對(duì)周期性溫濕度作用下混凝土內(nèi)部溫濕度場(chǎng)的模擬計(jì)算研究具有重要的實(shí)際意義。 本文圍繞周期性溫濕度作用下混凝土內(nèi)部溫濕度場(chǎng)的模擬計(jì)算，綜合利用多孔介質(zhì)力學(xué)、復(fù)合材料力學(xué)混凝土細(xì)觀力學(xué)均勻化方法，從水泥石-混凝土材料-混凝土構(gòu)件等不同尺度層次上，在水泥石內(nèi)部濕熱傳輸機(jī)理及模型、混凝土細(xì)觀力學(xué)變形機(jī)理及濕熱耦合變形數(shù)值模擬等方面，對(duì)濕-熱-力耦合作用下混凝土變形開裂多尺度模擬的相關(guān)機(jī)理、模型和數(shù)值模擬方法進(jìn)行研究。根據(jù)水泥石內(nèi)部典型孔分布情況，認(rèn)為在分析水泥石內(nèi)部濕熱傳輸時(shí)必須考慮濕度的Knudsen擴(kuò)散，并分析了考慮Knudsen擴(kuò)散的內(nèi)部濕傳輸機(jī)理，建立了相應(yīng)的濕傳輸模型；根據(jù)混凝土的三相（水泥石-過渡區(qū)-集料）組成模型、水泥石應(yīng)力應(yīng)變關(guān)系，利用復(fù)合材料力學(xué)原理研究了混凝土的應(yīng)力應(yīng)變關(guān)系；利用細(xì)觀力學(xué)均勻化方法，將混凝土的濕熱物理參數(shù)、基本力學(xué)參數(shù)看做均勻分布并通過水泥石、集料的相關(guān)參數(shù)進(jìn)行對(duì)算確定；參考熱膨脹系數(shù)的定義，考慮到實(shí)際應(yīng)用的方便性，初步提出了混凝土濕膨脹系數(shù)的概念、定義和理論計(jì)算公式的推導(dǎo)；基于多孔介質(zhì)濕熱傳輸原理和水泥石濕熱傳輸模型，研究了混凝土材料濕熱耦合變形數(shù)值模擬方法，并通過算例分析進(jìn)行了驗(yàn)證；對(duì)實(shí)際環(huán)境溫濕度變化特點(diǎn)、混凝土在實(shí)際溫濕度環(huán)境和受力條件下的變形開裂機(jī)理進(jìn)行了分析，并對(duì)混凝土構(gòu)件濕-熱-力耦合變形開裂數(shù)值模擬方法和可用軟件等進(jìn)行了討論和初步研究。 研究結(jié)果表明：考慮Knudsen擴(kuò)散影響的水泥石濕熱傳輸機(jī)理更為合理；提出的水泥基復(fù)合材料濕膨脹系數(shù)和理論計(jì)算公式及反演法確定方法具有可行性和實(shí)用性；基于多孔介質(zhì)濕熱傳輸原理的混凝土濕熱耦合變形模擬計(jì)算能夠反映混凝土內(nèi)部的濕熱耦合效應(yīng)，可以用于混凝土材料變形模擬分析；實(shí)際工程結(jié)構(gòu)混凝土變形開裂是濕-熱-力耦合作用的結(jié)果，且由于實(shí)際環(huán)境溫濕度變化的類周期性而存在類似疲勞損傷的作用；宜選用適合多物理場(chǎng)耦合分析的COMSOL Multiphysics軟件對(duì)濕-熱-力耦合作用下混凝土變形開裂行為進(jìn)行數(shù)值模擬。有關(guān)濕膨脹系數(shù)、濕-熱-力耦合作用下混凝土變形開裂機(jī)理等方面有待進(jìn)一步研究完善。
[Abstract]:The volume stability of concrete is also the main reason affecting the durability of concrete materials and structures . The durability deterioration process such as carbonation , chemical attack and reinforcement corrosion is more apt to be carried out after the concrete deformation and cracking , and the durability and service life of concrete are seriously damaged . The deformation cracking of concrete in practical engineering structure is the result of environmental temperature and humidity change and structural outer load , and it is of great practical significance for simulating calculation of temperature and humidity field in concrete under the action of periodic temperature and humidity .

In this paper , the relative mechanism , model and numerical simulation method of concrete deformation cracking multi - scale simulation under the action of wet - heat - force coupling are studied by simulating calculation of the temperature and humidity field in concrete under the action of periodic temperature and humidity , and the mechanism , model and numerical simulation method for the multi - scale simulation of concrete deformation cracking under the action of wet - heat - force coupling are studied .
According to the three - phase ( cement - transition zone - aggregate ) composition model of concrete , the stress - strain relation of cement stone is studied , and the stress - strain relation of concrete is studied by using the mechanics principle of composite material ;
The wet and heat physical parameters and basic mechanical parameters of the concrete are uniformly distributed and determined by the relevant parameters of the cement stone and aggregate by using the uniform method of the meso - mechanical homogenization ;
Referring to the definition of thermal expansion coefficient , considering the convenience of practical application , the concept , definition and calculation formula of concrete moisture expansion coefficient are preliminarily proposed .
Based on the principle of wet heat transfer of porous medium and the model of wet heat transfer of cement stone , the numerical simulation method of damp - heat coupling deformation of concrete is studied , and the example analysis is verified .
The deformation cracking mechanism of concrete under actual temperature and humidity environment and stress condition is analyzed , and the numerical simulation method and available software of wet - heat - force coupling deformation cracking of concrete members are discussed and studied .

The results show that the mechanism of wet heat transfer considering Knudsen diffusion is more reasonable .
The proposed method for determining the coefficient of wet expansion and theoretical calculation of the cement - based composite is feasible and practical .
The simulation calculation of concrete damp - heat coupling deformation based on the principle of wet heat transfer of porous medium can reflect the damp - heat coupling effect inside the concrete , and can be used for the simulation analysis of concrete material deformation ;
The concrete deformation cracking of the practical engineering structure is the result of the wet - heat - force coupling effect , and the effect of similar fatigue damage exists due to the periodicity of the temperature and humidity change of the actual environment .
The crack behavior of concrete under the action of wet - thermal - force coupling is numerically simulated by COMSOL Multiphysics software , which is suitable for multi - physical field coupling analysis .
【學(xué)位授予單位】：安徽工業(yè)大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2014
【分類號(hào)】：TU528

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