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，有必要了解其拓扑结构与细观性能和宏观性能之间的关系。在本研究中，我们提出了一种方法来模拟烧结球形颗粒的宏观性质(有效弹性常数和导热系数)，并通过原始随机堆积的统计特性来考虑宏观性质。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(连接球体中心的线段)取向的角度分布。到目前为止，人们已经理解，通过将球体顺序引入虚拟盒子而产生的随机堆积在结构上不受重力的影响，并且它们的结构是各向同性的。然而，目前对树枝取向的方位分布和天顶分布的分析表明，堆积结构的横向各向同性以及弹性和导电性的各向异性。另一方面，实验表明，由于重力对堆积的影响，烧结玻璃微珠骨料呈横观各向同性。这意味着，球形颗粒的顺序引入创造了类似于玻璃珠填充到真实盒子中的颗粒填充结构，从而验证了本文的模拟方法。

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.