Collaborative Proposal: Rheology and Flow of Geometrically Cohesive Granular Materials

这个项目研究了一类几何上有凝聚力的颗粒材料，例如一堆能抵抗拉力的颗粒。几何粘性颗粒材料（GCGM）的例子包括长而细的棒（如干草堆）和凹形颗粒（半圆或u形订书钉）。这些材料为基础研究和新的实际应用提供了丰富的机会，这些应用需要结构刚性、轻质和多孔性。计算机模拟和实验的各种颗粒形状-棒状，半圆形，和u形钉-将进行提供一个更好的微观和宏观的理解颗粒形状如何影响流化和凝固在GCGM。以前进行的表征球形颗粒介质的实验？基本流变学、翻滚、崩塌和流动？对于上述形状复杂的颗粒，将重复上述步骤。使用离散元方法的数值模拟将用于探测几何内聚发生的粒子级机制。涉及图形处理单元（gpu）的新的并行化技术将被开发用于模拟数千个粒子。这些实验和计算研究将用于探索几何内聚的可能普遍性，临界长度的缩放，以及这种内聚发生的基本机制。这项工作将增加对由复杂形状颗粒组成的颗粒材料的理解，这是许多工业过程中常见的现象。该项目还启动了两个机构之间的合作：一个主要的本科学院，罗切斯特理工学院和一个R1研究型大学，罗切斯特大学。该合作将使本科生和研究生参与丰富的教育体验，强调实验家和计算研究人员之间的交流。模拟和桌面实验将允许本科生在这两个机构从事前沿研究。

1133722 PI: Franklin1133722PI: TeitelThis project investigates a class of granular materials that are geometrically cohesive, e.g. a collective pile of particles that resists tensile forces. Examples of geometrically cohesive granular materials (GCGM) include long, thin rods (e.g. haystacks) and concave-shaped particles (semi-circles or U-shaped staples). These materials present a rich opportunity for basic research as well as new practical applications where structural rigidity, lightweight, and porosity are desired.Computer simulations and experiments for a variety of particle shapes - rods, semi-circles, and U-shaped staples - will be carried out to provide a better micro and macroscopic understanding of how particle shape affects fluidization and solidification in GCGM. Experiments previously carried out to characterize spherical granular media?basic rheology, tumbling, collapse, and flow ? will be repeated for the above complex-shaped particles. Numerical simulations using the Discrete Element Method will be used to probe the particle-level mechanism by which geometric cohesion occurs. New parallelization techniques involving graphics processing units (GPUs) will be developed for simulating thousands of particles. These experimental and computational studies will be used to explore the possible universality in geometric cohesion, the scaling of critical lengths, and the fundamental mechanism by which this cohesion occurs.This work will lead to increased understanding of granular materials consisting of complex shaped particles, a common occurrence in many industrial processes. The project also initiates collaboration between two institutions: a primarily undergraduate institute, Rochester Institute of Technology, and an R1 research university, University of Rochester. The collaboration will engage undergraduate and graduate students in a rich educational experience that emphasizes communication between experimentalists and computational researchers. Simulations and table-top experiments will allow undergraduates to engage in cutting edge research at both institutions.