摘要

Granular materials (sand, powders, etc.,) behave quite differently from traditional continuous medium such as elastic solids and simple liquids. This is since granular materials are by nature out of equilibrium systems because of the inelastic collisions and nonlinear friction between the particles. Despite the great need to have an accurate theoretical description of granular materials for engineering and geotechnical applications, there exist so far only empirical macroscopic descriptions of these materials. Therefore it is of fundamental importance to develop a theory for granular materials starting from its microscopic dynamics and structure.

In the present talk, I will first talk about the recent work about microscale relaxation dynamics of hard granular ellipsoids subject to an oscillatory shear, which demonstrate that the relaxation dynamics of such "frictional" systems is qualitatively different from that of "thermal" systems and that granular materials are "marginal solids", i.e. stable if unperturbed but fluid under the slightest external perturbation.
 

报告人简介

王宇杰，beat365中文版官方网站beat365中文版官方网站研究员，博士生导师。1995年在清华大学物理系获学士学位，2001年在麻省理工学院获物理学博士学位。博士毕业后在美国阿贡国家实验室从事博士后和助理研究员研究。2009年底在beat365中文版官方网站beat365中文版官方网站任职。教育部新世纪优秀人才支持计划、上海市浦江人才计划等，近年来主要从事同步辐射影像及以颗粒物质为代表的软物质物理研究。过去总共发表Nature，Nature Phys.，Nature Commun.，PRL在内文章50余篇，近五年以通讯作者身份以交大为第一单位发表Nature 1篇，Nature Commun. 2篇， PRL1篇等论文。