Geometric similarity on interparticle force evaluation for scaled-up DEM particles
Geometric similarity on interparticle force evaluation for scaled-up DEM particles
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DOI：
10.1016/j.powtec.2022.117483
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发表时间：
2022-05
影响因子：
5.2
通讯作者：
Yuze Hu;Ei L. Chan;T. Tsuji;Toshitsugu Tanaka;Kimiaki Washino
中科院分区：
文献类型：
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作者：
Yuze Hu;Ei L. Chan;T. Tsuji;Toshitsugu Tanaka;Kimiaki Washino
在离散元法中，为了减少计算量，常采用按比例放大的颗粒模型，也称为粗颗粒模型或离散块模型。在直接力缩放方法中，首先估计作用在原始颗粒上的力，然后直接缩放以应用于按比例放大的颗粒。因此，适当地评估原始颗粒的变量是至关重要的，例如，重叠和分离距离，从按比例放大的颗粒，特别是在估计复杂的颗粒间力时。本工作提出了使用几何相似性的评价原始颗粒的重叠和分离距离。它表明，所提出的方法可以提供一个几乎相同的应力-应变曲线之间的原始和放大的颗粒在单轴压缩的填充颗粒床，而在文献中的传统方法给出了显着高估的应力。此外，放大后的颗粒可以合理地复制原来的速度分布的粘性颗粒的液体桥和JKR表面粘附力在动态流动系统（垂直混合器）。模拟结果表明，所提出的方法可以适用于任何类型的颗粒间的力。本文还从理论上导出了时间步长极限的标度，并进行了讨论。
The scaled-up particle model, which is also commonly known as the coarse grain model or discrete parcel model, is frequently used to reduce the computational cost in Discrete Element Method (DEM). In the direct force scaling approach, the forces acting on original particles are first estimated and then directly scaled to apply to scaled-up particles. It is therefore crucial to appropriately evaluate the variables of the original particles, e.g. overlap and separation distance, from the scaled-up particles particularly when estimating complex interparticle forces. The present work proposes the use of geometric similarity for the evaluation of the original particle overlap and separation distance. It is demonstrated that the proposed method can provide an almost identical stress-strain curve between the original and scaled-up particles during uniaxial compression of a packed particle bed, whilst the conventional method in the literature gives significant overestimation of the stress. In addition, the scaled-up particles can reasonably replicate the original velocity distributions of cohesive particles with both liquid bridge and JKR surface adhesion forces in a dynamic flow system (vertical mixer). The simulation results suggest that the method proposed can be applied to any type of interparticle forces. A scaling of time step limit is also derived theoretically and discussed.