报告题目：         

Nonlinear dynamics of contact breaking in jammed solids

报告人:                 Prof. Corey S. O’Hern

Department of Mechanical Engineering & Materials Science, Department of Applied Physics, and Department of Physics, Yale University

时间：2016年8月10日(周三)  10:00—11:00  

地点：中国科学院力学研究所1号楼344会议室

报告摘要：

We perform computational studies of the response of mechanically stable packings of spherical particles near the onset of jamming to weak vibrations. Vibrations are added by displacing the packing along a single or a combination of eigenmodes of the dynamical matrix of the mechanically stable packing.  The frequency content of the vibrated system can be obtained from the Fourier transform of the particle displacements.  We first calculate and then confirm numerically the characteristic amplitude of the vibrations required to break the first interparticle contact in the packing as a function of overcompression Δϕ and system size N.  The characteristic amplitude at which the first interparticle contact breaks depends strongly on the frequency content of the initial perturbation and its subsequent evolution.   In addition, in overcompressed systems with m = > 0 contacts above the isostatic number, we measure the characteristic amplitude required to break m+1 interparticle contacts at which the system transitions from a solid-like to a liquid-like behavior.  Finally, we show preliminary studies of the thermal conductivity of the packings as a function of the amplitude and frequency content of the vibrations.  We find that the thermal conductivity is sensitive to the breaking and reforming of interparticle contacts.

报告人简介：

Corey is an Associate Professor with Tenure in the Departments of Mechanical Engineering & Materials Science, Applied Physics, and Physics and Graduate Program in Computational Biology & Bioinformatics at Yale. Before joining the faculty at Yale, he was a postdoctoral fellow working with Prof. Andrea Liu (UPenn, Physics) who was then at UCLA and Prof. Sidney Nagel (UChicago, Physics) on computational studies of jamming transitions in frictionless granular materials and glass transitions in model glass-forming liquids. Corey received his Ph.D. in Physics from the University of Pennsylvania in 1999; his dissertation focused on developing elasticity theories for liquid crystalline systems with biological importance such as DNA-cationic lipid complexes. Corey was an undergraduate at Duke University and graduated in 1994 with a B.S. in Physics. Corey has about 100 publications in archival journals covering topics in jamming, and many of appearing in PRL as classics in this field. These works receive more than 4000 times citations.