Apparent and effective physical properties of heterogeneous materials: Representativity of samples of two materials from food industry
Apparent and effective physical properties of heterogeneous materials: Representativity of samples of two materials from food industry
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DOI：
10.1016/j.cma.2005.07.022
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发表时间：
2006-01-01
影响因子：
7.2
通讯作者：
Singleton, Scott
中科院分区：
文献类型：
--
作者：
Kanit, Toufik;N'Guyen, Franck;Singleton, Scott
采用三维共焦图像对食品工业中两种材料A和B的有效弹性和热性能进行了研究，这两种材料由两种具有高度对比特性的组分组成，具有相同的体积分数但不同的形貌。为此，基于显式网格的微观结构的有限元模拟进行了六个样品的材料，不同的边界条件：运动均匀（KUBC），应力均匀（SUBC）和周期性的边界条件。对整个样品的直接模拟表明，KUBC和SUBC提供了强烈不同的表观性质，这引起了样品的代表性的问题。在[Kanit et al.，Determination of the size of the representative volume element for random composites：statistical and numerical approach，Int. J. Solids Struct.40（2003）3647-3679]在此扩展到真实的微结构的情况，以便估计两种材料的代表性体积元（RVE）的尺寸。材料A的样品被发现是有代表性的，而至少两倍大的样品体积将是必要的，以预测材料B的性能，精度为5%。从周期性边界条件的样品中提取的大量子域上使用模拟的有效性能的数值预测与现有的实验结果是令人满意的协议。特别地，材料A的硬度是材料B的两倍。这是由于材料中硬相的不同渗流行为，这在文章的最后一节中进行了研究。几何和机械渗流指标，特别是相关的连接微结构，提出和估计使用3D图像分析。(c)2005 Elsevier B. V.保留所有权利。
Three-dimensional confocal images of two materials A and B from food industry made of two constituents with highly contrasted properties, having the same volume fraction but different morphologies, are used to estimate their effective elastic and thermal properties. For that purpose, finite element simulations based on explicit meshing of the microstructures are performed on six samples of the materials, with different boundary conditions: kinematic uniform (KUBC), stress uniform (SUBC) and periodic boundary conditions. Direct simulations on the entire samples show that KUBC and SUBC provide strongly different apparent properties, which rises the question of the representativity of the samples. A numerical and statistical computational homogenization methodology first proposed for random models of microstructures in [Kanit et al., Determination of the size of the representative volume element for random composites: statistical and numerical approach, Int. J. Solids Struct. 40 (2003) 3647-3679] is extended here to the case of real microstructures in order to estimate the size of representative volume elements (RVE) for both materials. The samples of material A are found to be representative, whereas at least twice as large sample volumes would be necessary to predict the properties of material B with a precision of 5%. Numerical predictions of the effective properties using simulations on a large number of subdomains extracted from the samples with periodic boundary conditions are in satisfactory agreement with available experimental results. In particular, material A is twice as stiff as material B. This is due to a different percolation behaviour of the hard phase in the materials, which is investigated in the last section of the article. Indicators of geometrical and mechanical percolation, especially relevant for connected microstructures, are proposed and estimated using 3D image analysis. (c) 2005 Elsevier B.V. All rights reserved.