Ken Kamrin

Abstract: Granular media are common in industry, the natural world, and our day-to-day lives, but have been historically resistant to modeling.  While grain-by-grain discrete element methods (DEM) exist, these are often far too costly at the length- and time-scales of real-life problems. This talk progressively develops continuum-based tools for granular media with the aim of realistic but computationally tractable full-scale flow simulation.  We begin with a discussion of dry granular rheology and its essential ingredients.  We provide a brief discussion of what sorts of problems can be solved accurately with a basic granular flow model, and discuss a meshless numerical method, the Material Point Method (MPM), which can be used to simulate these models up to huge deformations.  We then discuss a relatively new way to exploit this capability to tackle more advanced problems where simple continuum models are not accurate enough.  In problems where regions of the flow may be too complex for the basic continuum model, we extend the framework into a DEM-continuum hybrid simulation method, which allows the problem domain to be split adaptively into MPM and DEM subdomains so as to provide grain-scale precision only where needed.  This hybridized, multi-scale approach is shown capable of delivering results that match full-scale DEM simulations but in far less computation time.  We will discuss the various aspects of the framework needed to hybridize DEM and continuum simulations. 

Bio: Ken Kamrin received a BS in Engineering Physics with a minor in Mathematics at UC Berkeley in 2003, and a PhD in Applied Mathematics at MIT in 2008.  Kamrin was an NSF Postdoctoral Research Fellow at Harvard University in the School of Engineering and Applied Sciences before joining the Mechanical Engineering faculty at MIT in 2011, where he was appointed the Class of 1956 Career Development Chair and later received a second faculty appointment in Applied Mathematics.  After 13 years as a professor at MIT, Ken joined the UC Berkeley Mechanical Engineering faculty in 2024.  Kamrin’s research focuses on constitutive modeling and computational mechanics for large deformation processes, with interests spanning elastic and plastic solid modeling, granular mechanics, amorphous solid mechanics, and fluid-structure interaction.  Kamrin’s honors include the 2010 Nicholas Metropolis Award from APS, the NSF CAREER Award in 2013, the 2015 Eshelby Mechanics Award for Young Faculty, the 2016 ASME Journal of Applied Mechanics Award, and the 2022 MacVicar Faculty Fellowship from MIT.  He sat for three years on the Board of Directors of the Society of Engineering Science and serves as an associate editor for the International Journal of Solids and Structures, Granular Matter, and Computational Particle Mechanics.