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报告题目：Jamming of Deformable Particles

报告人：Prof. Corey S. O'Hern

        Yale University，USA

时间：2019年7月11日下午14:00

地点：北京理工大学3号教学楼201会议室

报告人简介：

Corey O'Hern is a Full Professor in the Department of Mechanical Engineering and Materials Science at Yale University with secondary appointments in Applied Physics, Physics, and the Graduate Program in Computational Biology & Bioinformatics.  He received his Ph.D. in Physics from the University of Pennsylvania in 1999 and then was a postdoctoral fellow at the University of Chicago and UCLA until 2002. In 2017, he was selected as a Fellow of the American Physical Society.

Corey is an expert in computational studies of granular media, which are composite materials made up of macroscopic grains with frictional interactions. Examples include sand piles, powders, and animal nests. His research focuses on predicting when granular materials are jammed and behave as solids and when they are unjammed and behave as fluids. His research group is currently funded by seven active awards from the National Science Foundation, W. M. Keck Foundation, Army Research Office, and the National Institutes of Health and he has more than 115 published research articles.

报告摘要：

We introduce the deformable particle (DP) model for cells, foams, emulsions, and other soft particulate materials, which adds to the benefits and eliminates deficiencies of existing models. The DP model combines the ability to model individual soft particles with the shape-energy function of the vertex model, and adds arbitrary particle deformations. We focus on 2D deformable polygons with a shape-energy function that is minimized for area a_0 and perimeter p_0 and repulsive interparticle forces. We study the onset of jamming versus particle asphericity, A= p^_2 0=4/pi a0, and find that the packing fraction grows with A until reaching A^* /approx 1.16 of the underlying Voronoi cells at confluence. We find that DP packings above and below A^* are solidlike, which helps explain the solid-to-fluid transition at A in the vertex model as a transition from tension- to compression-dominated regimes.