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Particuology 2019年第6期17卷 41-53页

作者： Jianjun Lin huisu chen Jiangsu Key Laboratory of Construction Materials School of Materials Science and EngineeringSoutheast UniversityNanjing 211189China

The influence of particle characteristics,such as shape,size,and volume fraction,on the permeability of porous media was investigated by combining the randomly packed beds of Platonic particles with the lattice Boltzmann *** solutions of the permeability as a function of these characteristic parameters in mono-sized particle packing structures were *** D3Q19 model is presented here,which was tested by three simple benchmark tests.A series of packed beds of Platonic particles as well as spherical particles were generated in a random *** studies on factors influencing the permeability of materials were carried out to comprehensively study their *** results revealed that the permeability significantly increased with increasing equivalent diameter of the particles(or decreasing volume fraction).At a fixed size and volume fraction of particles,the permeability of the Platonic particle packing structures was also influenced by particle morphology:permeability significantly reduced as the particle sphericity *** permeability of tetrahedral particle packing structures dropped by more than 40%compared with that of corresponding spherical particle systems.

关键词： Platonic particles Lattice Boltzmann method Granular media Fluid flow Particle characteristics

Continuum percolation of porous media via random packing of overlapping cube-like particles

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Theoretical & Applied Mechanics Letters 2018年第5期8卷 299-303,361页

作者： Jianjun Lin huisu chen Jiangsu Key Laboratory of Construction Materials School of Materials Science and EngineeringSoutheast University

The pore configuration in porous medium is assumed to be the randomly distributed cube-like particles which can overlap each other in the periodic cubic domain, and the impact of particle characteristics on the percolation property of these cube-like particle packing systems is ***, by combining the percolation models and finite-size scaling analysis, three numerical parameters(i.e., percolation transition width △L, local percolation threshold ψ_c(L), and correlation length exponent v) for the cube-like particle systems with shape parameter s in[1.0, +∞] are derived successively. Then, based on the relation between the percolation thresholdψ_c in infinite space and the local percolation threshold ψ_c(L), the corresponding ψ_c with s in[1.0, +∞] are further determined. It is shown from the study that the characteristics of cube-like particles have significant influence on the global percolation threshold ψ_c of the particle packing systems. As the parameter s increases from 1.0 to +∞, the percolation threshold ψ_c will go down persistently. When the surface of cube-like particles is cubical and spherical, respectively, the minimum and maximum thresholds ψ_c,min and ψ_c,max are obtained.

关键词： Cube-like particles Porous medium Percolation Finite-size scaling analysis Simulation and modeling

Effects of grain's shape-and size-polydispersities,orientation,and area fraction on tortuosity and permeability of 2D granular media

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Particuology 2024年第7期90卷 535-557页

作者： Ke Cao huisu chen Mohammad Iqbal Khan Mingqi Li Lin Liu Jiangsu Key Laboratory of Construction Materials School of Materials Science and EngineeringSoutheast UniversityNanjing 211189China Department of Civil Engineering College of EngineeringKing Saud UniversityP.O.Box 800Riyadh 11421Saudi Arabia School of Civil and Transportation Engineering Hebei University of TechnologyTianjin 300401China College of Civil and Transportation Engineering Hohai UniversityNanjing210098China

The microstructure of granular media, including grain's shape- and size-polydispersities, orientation, and area fraction can potentially affect its permeability. However, few studies consider the coupling effects of these features. This work employs geometrical probability and stereology to establish quantitative relationships between the above microstructural features and the geometric tortuosity of the two-dimensional granular media containing superellipse, superoval, and polygon grains. Then the lattice Boltzmann method (LBM) is used to determine the permeabilities of these granular media. By combining the tortuosity model and the LBM-derived permeabilities, modified K–C equations are formulated to predict the permeability and the shape factor, considering the grain's shape- and size-polydispersities, orientation, and area fraction. The reliability of these methods can be verified by comparing them with both our simulations and available experimental, theoretical, and numerical data reported in the literature. The findings implicate that the tortuosity and permeability of the granular media are strongly correlated with the grain's shape, orientation, and area fraction but unaffected by the size polydispersity and spatial arrangement of grains. Only circularity is not enough to derive a unified formula for considering the impact of grain shape on tortuosity and permeability, other shape parameters need to be explored in the future.

关键词： Geometric tortuosity Konzey-Carman equation Shape and size ploydispersities Grain orientation Lattice Boltzmann method Granular media

Numerical evaluation of overestimation of the interface thickness around ellipsoidal particle

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Theoretical & Applied Mechanics Letters 2013年第5期3卷 39-41页

作者： Wenxiang Xu huisu chen Wen chen Institute of Soft Matter Mechanics College of Mechanics and Materials Hohai University Jiangsu Key Laboratory of Construction Materials College of Materials Science and EngineeringSoutheast University

Abstract When interfacial layers are viewed as a separate phase, the interface thickness plays an essential role in assessing physico-mechanical properties of particulate materials. However, the interface thickness from sectional analysis is often overestimated, due to the irregularity of surface textures of grains in opaque materials that gives rise to the normal of a cross-sectional plane non-perpendicular to the surface of grains. Hence, the determination of the overestimation degree is very critical to precisely obtain the interface thickness. This article develops a numerical model for the overestimation degree of the interface thickness around an ellipsoidal grain with an arbitrary aspect ratio, by applying an accurate sectional analysis algorithm, and quantitative stereology and geometrical probability theories. Furthermore, on the basis of the developed numerical model, the influence of ellipsoidal particle shape on the overestimation degree is quantitatively charac-terized.

关键词： multiphase materials interface thickness ellipsoidal particle overestimation model

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引气混凝土气泡尺寸分布的三维重构

材料研究学报 2007年第6期21卷 613-621页

作者：陈惠苏孙伟东南大学江苏省土木工程材料重点实验室

基于体视学和几何概率理论给出了引气混凝土三维气泡尺寸重构方法,由二维平面上气泡截面圆的直径分布计算气孔的实际尺寸分布,并生成了一个多尺度分布的立方体模型结构验证了该三维重构方法的合理性.然后,使用邻近粒子表面最近间距的解... 详细信息

基于体视学和几何概率理论给出了引气混凝土三维气泡尺寸重构方法,由二维平面上气泡截面圆的直径分布计算气孔的实际尺寸分布,并生成了一个多尺度分布的立方体模型结构验证了该三维重构方法的合理性.然后,使用邻近粒子表面最近间距的解析解研究了气泡细度和混凝土含气量对邻近气泡表面最近间距平均值的影响,并与用传统方法得到的气泡间距因子进行了比较.结果表明,在含气量相同的条件下,用传统方法得到的气泡间距因子是邻近气泡表面最近间距平均值的3—4倍.该方法的给出,为从二维截面上获得的引气混凝土中的气泡截面圆信息获取实际气泡在三维空间中的气泡间距信息提供了依据.

关键词：无机非金属材料引气混凝土间距因子气泡尺寸分布三维重构

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多元水泥基系统的性能预测及优化设计

硅酸盐学报 2001年第2期29卷 97-103页

作者：陈惠苏孙伟东南大学材料科学与工程系南京210096

以水泥 -硅灰 -粉煤灰三元净浆系统的抗压强度为例 ,研究了单纯形 -格子设计方法在水泥基复合材料性能预测领域中的应用 ,并从统计学的角度 ,采用F检验方法分析了如何得到一个合理的性能预测回归方程 .此外 ,本工作还研究了最优化理论... 详细信息

以水泥 -硅灰 -粉煤灰三元净浆系统的抗压强度为例 ,研究了单纯形 -格子设计方法在水泥基复合材料性能预测领域中的应用 ,并从统计学的角度 ,采用F检验方法分析了如何得到一个合理的性能预测回归方程 .此外 ,本工作还研究了最优化理论在水泥基复合材料配合比设计领域中的应用 .研究结果表明 :(1)采用单纯形 -格子设计方法得到的三阶回归模型能够很好地预测混合材掺量不大于 30 %的水泥 -硅灰 -粉煤灰三元净浆系统中任意配合比点各龄期的抗压强度值 ;(2 )通过对兼有上、下界约束的非线性规划问题的求解 ,得到了各龄期最优抗压强度所在点的配合比及最优强度值 ;(3)单纯形

关键词：水泥基材料性能预测配比优化单纯形-格子设计非线性规划 F检验

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水泥基材料裂缝自主愈合研究进展

硅酸盐学报 2014年第2期42卷 156-168页

作者：吕忠陈惠苏安徽工业大学建筑工程学院安徽马鞍山243032 东南大学材料科学与工程学院江苏省土木工程材料重点实验室南京211189

评述了近年来国内外有关水泥基材料裂缝自主愈合的发展状况,从载体形貌的角度重点综述了管状载体和球形载体的破裂方式以及修复剂释放机理、修复效果的表征方法,特别是载体形貌对愈合行为的影响及有关载体掺量模型研究方面所取得的成果... 详细信息

评述了近年来国内外有关水泥基材料裂缝自主愈合的发展状况,从载体形貌的角度重点综述了管状载体和球形载体的破裂方式以及修复剂释放机理、修复效果的表征方法,特别是载体形貌对愈合行为的影响及有关载体掺量模型研究方面所取得的成果;分类阐述了常用修复剂的品种、性能和种类以及修复剂选取所需考虑的环境因素,简述了载体封装材料和载体制备方法等发展状况;分析了水泥基材料裂缝自主愈合研究所存在的问题,展望了其发展趋势和发展前景。

关键词：水泥基材料自主愈合裂缝载体修复剂

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冻融破坏下水泥基材料中裂缝连通行为的模拟

东南大学学报（自然科学版） 2010年第A2期40卷 126-132页

作者：袁海峰陈惠苏东南大学江苏省土木工程材料重点实验室南京211189 东南大学材料科学与工程学院南京211189

为了对水泥基复合材料在经受冻融破坏时其内部的损伤变量进行表征,提出了预测不同温度下,由于冻胀破坏造成的裂缝在基体中连通行为的方法.从温度以及孔隙尺寸对孔隙中水的冰点的影响出发,得到了在不同温度下基体中发生结冰行为的孔隙分... 详细信息

为了对水泥基复合材料在经受冻融破坏时其内部的损伤变量进行表征,提出了预测不同温度下,由于冻胀破坏造成的裂缝在基体中连通行为的方法.从温度以及孔隙尺寸对孔隙中水的冰点的影响出发,得到了在不同温度下基体中发生结冰行为的孔隙分布,进而利用计算机模拟产生由于这些结冰孔导致的裂缝,并对其联通行为进行了计算.模拟结果表明:在降温初期,裂缝的连通性变化很快;在后期虽然裂缝的数量增加,但裂缝的连通性变化不大;冻胀破坏对连通性的影响主要体现在大孔的体积分数上而小孔(小于10nm)的数量则在降温时对基体连通性的影响很小.

关键词：冻融破坏裂缝连通性计算机模拟

球形/球柱形微胶囊自修复水泥基复合材料修复效率数值模拟

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硅酸盐学报 2021年第2期49卷 357-364页

作者：吕忠熊庭倩陈惠苏安徽工业大学建筑工程学院安徽马鞍山243032 东南大学材料科学与工程学院南京211189

水泥基复合材料因其固有的脆性和较低的抗拉强度,在工程结构中不可避免会发生开裂。胶囊法自修复系统为水泥基材料基体开裂的修复和延缓潜在危害提供了一种可行的方法。借助扩展有限元方法,模拟了微胶囊自修复水泥基模型材料内微裂缝的... 详细信息

水泥基复合材料因其固有的脆性和较低的抗拉强度,在工程结构中不可避免会发生开裂。胶囊法自修复系统为水泥基材料基体开裂的修复和延缓潜在危害提供了一种可行的方法。借助扩展有限元方法,模拟了微胶囊自修复水泥基模型材料内微裂缝的产生、扩展、断裂过程及胶囊破裂行为,验证了裂缝迫使胶囊发生破裂的概率;应用复合材料理论,计算出了不同掺量下球形/球柱形微胶囊修复前后水泥基复合材料的有效弹性模量,表征了该复合材料的修复效率。

关键词：水泥基材料自修复微胶囊有效弹性模量扩展有限元

水泥基复合材料界面过渡区体积分数的定量计算

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复合材料学报 2006年第2期23卷 133-142页

作者：陈惠苏孙伟 STROEVEN Piet 东南大学材料科学与工程系南京210096 Faculty of Civil Engineering and Geosciences Delft University of Technology P.O.Box 50482600GA DelftThe Netherlands

借助邻近函数公式,给出了水泥基复合材料集料与浆体间界面过渡区体积分数的定量计算公式,并采用随机点采样方法验证采用该定量公式计算水泥基复合材料界面过渡区体积分数的可行性。在此基础上,预测了由符合Fuller分布的集料制备的混凝... 详细信息

借助邻近函数公式,给出了水泥基复合材料集料与浆体间界面过渡区体积分数的定量计算公式,并采用随机点采样方法验证采用该定量公式计算水泥基复合材料界面过渡区体积分数的可行性。在此基础上,预测了由符合Fuller分布的集料制备的混凝土中界面过渡区体积分数随集料体积分数和集料粒径范围的变化曲线。讨论了界面厚度变化、集料体积分数变化以及集料粒径分布变化对界面过渡区体积分数影响的差别,并给出了衡量界面过渡区重叠程度的定性和定量方法。结果表明:在常规集料体积分数下,三者中对界面过渡区体积分数以及界面过渡区重叠程度影响的主次顺序均为:界面过渡区厚度变化带来的影响>集料体积分数变化带来的影响>集料细度变化带来的影响。

关键词：界面过渡区体积分数最邻近表面分布函数 Fuller分布粒径分布混凝土