Dr. Wei Li Co-Authors Paper in Journal PNAS

 

 

 

 

Dr. Wei Li, assistant professor of civil engineering, recently published a paper in Proceedings of the National Academy of Sciences, one of the most prestigious and highly cited multidisciplinary research journals. This paper introduces a new tomographic imaging technique to study granular media called Interference Optical Projection Tomography (IOPT), which was developed during Dr. Li’s postdoc years in Professor Ruben Juanes’ laboratory at MIT. 

 

We civil engineers work with granular media all the time, from the soils we build our houses upon to the crushed rocks we add to our concrete. We all know that a granular medium composed of angular particles is more robust than that composed of round particles. Yet, the grain-scale interactions among the particles that lead to these dramatically different behaviors are not always clear. Dr. Li and Dr. Juanes provide a new grain-scale perspective on this phenomenon using IOPT to reconstruct the force chains—the chains of contacts among grains where forces are transmitted—in 3D packs of angular particles and round particles. They show that in response to an increasing vertical load, the pack of round particles forms intensifying vertical force chains, while the pack of angular particles forms more interconnected force-chain networks, which are more resistant to shear failure. 

 

Dr. Li's IOPT can help us better understand the grain-scale underpinnings of landslides and earthquakes and better engineer granular material used in construction in the future. This work was featured in MIT News and MIT Spotlight.