Earthquake surface fault rupture poses a significant natural hazard to infrastructure safety. Predicting and mitigating this hazard has long been a central challenge in engineering. In this project, Discrete Element Modeling (DEM) is employed to simulate the influence of various embedded weak zones on the diversion of earthquake surface fault ruptures, including reverse, normal dip-slip, and strike-slip ruptures. DEM offers grain-scale insights that are often difficult to capture using continuum-based approaches. The spatial configurations of the weak zones were systematically analyzed, and the effectiveness of different arrangements in diverting fault ruptures was quantitatively assessed. The study also provides physical interpretations to explain the observed diversion mechanisms. The findings is a step forward to inform and guide industry practices in infrastructure retrofitting to enhance resilience against fault rupture hazards. 

Biomass-to-biofuel conversion holds significant promise for reducing carbon emissions. However, the handling of biomass particles, such as wood chips, often faces challenges like arching and clogging in processing equipment. Developing advanced simulation tools to model the complex flow behavior of these particles offers both scientific insights and industrial benefits. In this project, a GPU-accelerated Smoothed Particle Hydrodynamics (SPH) solver was developed to simulate this unconventional granular flow. A hypoplastic model, originally formulated for soils, was adapted to the SPH framework, and a predictor-corrector scheme was derived to accurately treat frictional boundary conditions. The solver was successfully validated against experimental data. It demonstrates strong capabilities in simulating biomass flow through hoppers and augers, providing new insights into clogging mechanisms. Beyond biomass handling, the code also shows promise for simulating landslides, debris flows, soil-structure interactions, and other large-deformation processes in geomaterials. The solver is available as open-source:  DualSPHysics-INL.

Drilling is essential for subsurface construction and accessing underground energy resources, ranging from conventional oil and gas to renewable geothermal energy. However, compared to the efficiency of natural drilling mechanisms found in organisms, human-made technologies still face challenges such as low penetration rates, rapid drill bit wear, and high operational costs. This project investigates Cyrtopleura costata, a unique bivalve clam capable of boring into rock. Through tomographic imaging, analytical modeling, and prototype testing, the morphological advantages of its shell—particularly the arrangement of surface denticles—were found to contribute to efficient rock cutting. Nano-mechanical testing and micro-imaging revealed that the shell’s microstructure offers protection against damage. Discrete Element Modeling (DEM) further demonstrated that the collective cutting action of the denticles reduces the overall cutting effort. These findings underscore the potential of biomimicry to inspire and advance next-generation drilling technologies. 

The swimming behavior of active bacteria can significantly alter fluid properties, sometimes in counterintuitive ways—such as the reduction of fluid viscosity by motile E. coli at low shear rates. This project investigates how motile E. coli influence fluid interfacial tension and droplet drying patterns through a series of controlled experiments. The bacteria were observed to preferentially attach to fluid interfaces, altering both interfacial tension and interfacial rheological behavior. Distinct crystallization patterns emerged in dried droplets depending on the presence of E. coli. These observations contribute to a deeper understanding of bacteria-fluid interactions, which are critical in biological flows through porous media and may inform future strategies for manipulating subsurface flows using active bacteria.