Simulated Macro-Properties of Sintered Spherical Particles by Random Structure Model and Experiments

为了更好地利用多孔材料并对其性能进行评价，有必要了解多孔材料的拓扑结构与宏观、细观性能之间的关系。在本研究中，我们提出了一种方法来模拟的宏观性质（有效弹性常数和导热系数）的烧结球形颗粒，并考虑了宏观性质，通过原始随机填料的统计特性。作为新的统计参数，我们引入了横截面上出现的圆的直径的累积分布和分支（连接接触的球体中心的线段）的取向的角分布。到目前为止，人们已经知道，通过将球体顺序引入虚盒中所产生的随机堆积的结构不受重力的影响，并且它们的结构是各向同性的。然而，目前的分析的方位角和顶点分布的分支的取向显示横观各向同性的包装结构和各向异性的弹性和导电性。另一方面，由于重力对堆积的影响，烧结玻璃珠集料是横观各向同性的。这意味着球形颗粒的顺序引入在真实的盒子中产生了类似于玻璃珠填充的颗粒填充结构;因此本模拟方法是有效的。

In order to utilize porous materials and estimate their properties, it is necessary to understand relations between their topology and meso-scale properties and macro ones. In the present research, we proposed a method to simulate macro-properties (effective elastic constants and themal conductivity) of sintered spherical particles and considered the macro-properties through statistical characteristics of original random packings. As new statistical parameters, we introduced cumulative distribution of diameter of circles appearing on a cross-section and angular distribution of the orientations of branchs (line segments connecting the centers of spheres in contact).It had been so far understood that the random packings generated by sequential introduction of spheres into a virtal box were not affected in their structure by gravity and that their structure was isotropic. However, the present analysis of the azimuthal and zenithal distributions of the orientation of branches showed transaverse isotropy of the packing structures and the anisotropy in elasticity and conductivity. On the other hand, it followed from the experiment that sintered glass-bead agregates were transversely isotropic due to the gravity effect on packing. This means that the sequential introduction of spherical particles creates the structure of particle packing similar to glass-bead packing into a real box ; thus the present simulation method is validated.