Li Research Group
Mechanics and physics of complex material systems
Welcome!
We are a multidisciplinary team studying the (complex) mechanics and physics of (seemingly simple) material systems, especially those involving multi-body contact, friction, and fracture. We explore fundamental questions such as: What role does frictional contact play in controlling the macroscopic behavior of granular media? How (and why) does a fast crack behave (the way it does) in the presence of material heterogeneity?​
Our overarching goal is to quantitatively characterize their macroscopic behaviors, understand the underlying small-scale processes, and harness this knowledge for novel engineering applications that enhance the resilience and sustainability of our built environment. To this end, we develop and apply computational and experimental techniques that integrate concepts from solid mechanics, soft matter physics, and optical diagnostics. ​
Rearrangement
Phase transition
Frictional slip
Macro scale
Particle scale
Contact scale
Solid mechanics
Soft matter physics
Optical diagnostics
Our current research areas include the physics of nonlocality in disordered granular media, mechanics of granularity-inspired meta-materials, and multi-modal characterization of dynamic (brittle) fracture in natural and engineered materials.
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Event: A fast crack initiates and propagates in a notched glass-ceramic sample
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Crack speed: ~ 1500 m/s
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Observation length scale: ~1 mm
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Observation time scale: ~1 us
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Framing rate: 5 Mfps
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Technique: Synchrotron-sourced time-resolved X-ray phase contrast imaging (XPCI)​​​