Collaborative Proposal: Rheology and Flow of Geometrically Cohesive Granular Materials

1133722 PI：Franklin 1133722 PI：Teitel该项目研究一类几何上有粘性的颗粒材料，例如抵抗张力的颗粒的集合堆。 几何粘性颗粒材料（GCGM）的实例包括细长杆（例如干草堆）和凹形颗粒（半圆形或U形斯台普斯）。这些材料为基础研究以及新的实际应用提供了丰富的机会，其中结构刚度，重量轻，和多孔性是理想的。计算机模拟和各种颗粒形状的实验-棒，半圆形，U形斯台普斯-将进行颗粒形状如何影响GCGM流化和固化提供更好的微观和宏观的理解。以前进行的实验，以表征球形颗粒介质？基本流变学、翻滚、坍塌和流动？将对上述复杂形状的颗粒重复上述步骤。使用离散元方法的数值模拟将被用来探测几何凝聚力发生的颗粒级机制。将开发涉及图形处理单元（GPU）的新并行化技术，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凝聚力的可能普适性、临界长度的缩放以及这种凝聚力发生的基本机制。这项工作将有助于加深对由复杂形状颗粒组成的颗粒材料的理解，这在许多工业过程中很常见。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获得丰富的教育经验，强调实验学家和计算研究人员之间的沟通。 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.