Predicting how macroscale particles self-assemble

Prof. Corey S. O’Hern is an Associate Professor of Mechanical Engineering & Materials Science, Applied Physics, and Physics at Yale, whose research group employs computational techniques, such as molecular dynamics and discrete element modeling, Monte Carlo simulations, and Markov chains to study soft materials, biological systems, and particulate media.

Along with co-PIs Prof. Bulbul Chakraborty from Brandeis University and Robert Berhinger from Duke University, Prof. O’Hern was recently awarded a prestigious $1 million grant from the W.M. Keck Foundation to develop the first comprehensive theoretical framework for predicting how macroscale particles—from grains of sand to coffee beans—self-assemble into large collections with mechanical properties that resemble, but are distinct from traditional solids.

In microscale and nanoscale systems, thermal fluctuations govern the self-assembly process. In contrast, assemblies of macroscale particles do not experience thermal fluctuations and instead become trapped in a variety of unpredictable states that depend on the precise process used to create them.

Studies of macroscale particulate media are extremely computationally demanding because one must generate and characterize all possible particle configurations that can be generated by a given process and then consider all relevant processes. With funding from the W.M. Keck Foundation, Yale High Performace Computing has provided the O’Hern group with more than 128 computer processors to generate and characterize hundreds of millions packings composed of spherical and nonspherical frictional particles.

These studies of macroscale assemblies will have significant impact in systems that span erosion, earthquake faults, and industrial flows.