Our research interests are in the broad area of multi-physics theoretical, computational, and experimental mechanics of materials, with a focus on the development of continuum mechanics theories. In energy-storage materials, our work focuses on investigating two important concepts:
– How the mechanical behavior of a systems affects its energy storage behavior, and vice versa; and
– How the coupling between mechanics and chemistry can be harnessed to improve the energy storage performance of a material system.
Chemo-Mechanics of Nano-Architected Electrodes
This research project aims to develop the necessary numerical tools for modeling the electro-chemical performance of nano-architected electrodes, including their performance when undergoing elastic instabilities such as buckling. Our fully-coupled diffusion-deformation theory — and numerical implementation — is used to predict the electrochemical performance of a given nano-architecture as well as predict its mechanical performance and resilience during lithiation. Info/Videos/Publications.
Collaborators: The Greer Group at Caltech who perform all of the experiments.
Funding: National Science Foundation, CMMI, Mechanics of Materials and Structures (MOMS) Program.
Environmental Induced Degradation of Al-Mg Alloys
This research project aims to develop an experimentally validated numerical framework for understanding and predicting microstructural effects on environmental induced cracking (EIC) of Aluminum Magnesium alloys. We are developing a fully-coupled deformation-diffusion theory for hydrogen migration within the microstructure of the alloys accounting both for bulk grain and grain boundary chemo-mechanical behavior. Along with detailed experiments the framework will be numerically validated and used to analyze the relevant microstructural descriptors which yield alloys with improved EIC behavior.
Collaborators: The Kacher Lab at Georgia Tech is performing all of the experimental work.
Funding: US Air Force Academy’s Center for Aircraft Structural Life Extension (CAStLE)
Robotic Landing Gear for Rotorcraft
This project involves the design, manufacturing, and flight testing of a robotic landing gear (RLG) concept for rotorcraft. In collaboration with Boeing, the RLG system is being developed for a ~400lb Unmanned Aerial Vehicle. Through this project the team developed a novel four-bar cable-driven leg mechanism as well as novel ground contact sensors based on rubber encapsulated pressure sensors. Both technologies which are currently being patented. Info/Videos/Publications.
Collaborators: Mark Costello (GT), Julian J. Rimoli (GT).
Funding: DARPA Tactical Technology Office (TTO), Air Force Research Laboratory (Concluded),
Air Force STTR (Current).
In this work we formulate, numerically implement, and calibrate, a fully-coupeld diffusion-deformation theory for amorphous Silicon anodes. The theory accounts for transient diffusion of Li and accompanying large elastic-plastic deformations. We show that our numerical simulations are in good agreement with expereimntally-measured voltage vs. state-of-charge (SOC) behavior. Info/Videos/Publications
Unified framework of balance laws and thermodynamically-consisten constituve equations which couple Cahn-Hilliard-type species diffusion with large elastic deformations of a body. The developed numerical tool is used to study the combined effects of diffusion and stress on the lithiation of spheroidal-shaped particles. Info/Videos/Publications
We formulated a thermo-chemo-mechanically coupled-theory which accounts for diffusion of hydrogen and large elastic-plastic deformations of metals. The theory accounts for the trapping of hydrogen at microstructural defects and places the notion of an equilibrium between trapped and diffusing hydrogen within a thermodynamically-consistent framework. Info/Videos/Publications
Characterizing Interfacial Failure in Thermal Barrier Coatings (TBCs)
In this work, we developed an experimental-plus-simulation approach to determine the relevant material parameters appearing in a traction-separation-type law for modeling delamination failures in TBCs. Info/Videos/Publications.