The internal structure of composite materials is usually composed of a continuous matrix with dispersed particles. To simulate the spatial distribution of particles, the random sequential addition algorithm (RSA) is commonly used. The RSA using continuous geometric function is difficult to achieve a high packing density in allowable computer time and time-consuming in the case of irregularly shaped aggregates, such as in mortar and concrete systems. In this work, a geometrical model, named as VOX, is introduced to deal with 3D irregularly shaped particles. The model applies the voxel-based overlap determination in the RSA to improve the efficiency and packing density. Also, the model is applicable to the complex boundary conditions of any geometry and provides high-quality triangle meshes valuable for finite element analysis. The mortar and concrete cubes with real-shape particles are simulated, in which the packing density is increased to 65% and 51%, respectively. The VOX model successfully packs over 150,000 real-shape aggregates into the steel cage in a full-size reinforced concrete beam model on a desktop machine. Particle shape significantly affects the packing density in the RSA and the sphericity is recommended as an indicator. The particles with higher sphericity can achieve denser packing under the same effort of attempts. Real-shape gravel used in this study behaves similarly with regular octahedron because of the similar sphericity.

中文翻译：

---

VOX 模型：基于体素的填充算法在具有 3D 不规则形状颗粒的水泥基复合材料上的应用

复合材料的内部结构通常由具有分散颗粒的连续基体组成。为了模拟粒子的空间分布，通常使用随机顺序加法算法（RSA）。在不规则形状的骨料的情况下，例如在砂浆和混凝土系统中，使用连续几何函数的 RSA 难以在允许的计算机时间和耗时内实现高填充密度。在这项工作中，引入了一个名为 VOX 的几何模型来处理 3D 不规则形状的粒子。该模型在 RSA 中应用了基于体素的重叠确定，以提高效率和包装密度。此外，该模型适用于任何几何的复杂边界条件，并提供对有限元分析有价值的高质量三角形网格。模拟了具有实形颗粒的砂浆和混凝土立方体，其中填充密度分别增加到 65% 和 51%。VOX 模型在台式机上的全尺寸钢筋混凝土梁模型中成功地将 150,000 多个实形骨料装入钢笼中。颗粒形状显着影响 RSA 中的堆积密度，建议将球形度作为指标。在同样的努力下，具有更高球形度的颗粒可以实现更致密的堆积。由于相似的球形度，本研究中使用的实形砾石与正八面体的行为相似。在台式机上的全尺寸钢筋混凝土梁模型中，将 000 个实形骨料放入钢笼中。颗粒形状显着影响 RSA 中的堆积密度，建议将球形度作为指标。在同样的努力下，具有更高球形度的颗粒可以实现更致密的堆积。由于相似的球形度，本研究中使用的实形砾石与正八面体的行为相似。在台式机上的全尺寸钢筋混凝土梁模型中，将 000 个实形骨料放入钢笼中。颗粒形状显着影响 RSA 中的堆积密度，建议将球形度作为指标。在同样的努力下，具有更高球形度的颗粒可以实现更致密的堆积。由于相似的球形度，本研究中使用的实形砾石与正八面体的行为相似。