Nicole Dorcy of Northwestern University Wins Women in Focus 2024 R&D Award

ACI is delighted to announce Nicole Dorcy, Fourth Year PhD Candidate in Mechanical Engineering at Northwestern University, as the winner of our Women in Focus 2024 R&D Award.

Working with Professor Q. Jane Wang at the Center for Surface Engineering and Tribology, her work utilizes computational methods such as molecular dynamics and finite element analysis to study the solid mechanics and fluid dynamics at contact interfaces where asperities are present.

One tricky issue of mixed lubrication modeling is that once a contact is formed, the flow in the sliding direction is cut off. This causes a complicated fluid-solid interface that has never been addressed in computational tribology, suggesting that the existing numerical solutions for mixed lubrication (with co-existing asperity contact and fluid lubrication) is inaccurate at the vicinity of asperities. Because of liquid adsorption to surfaces, it is reasonable to assume that the no-slip boundary condition apples at the liquid-solid interface, and the liquid touching the surface should follow the motion status of the surface. This has been the essential condition for the Reynolds equation, and all modifications to the no-slip condition have been done for full-film lubrication without considering asperity contact. The asperity contact blocks the flow, and the flow has to be slowed down and stopped before it reaches the asperity-contact tip. This violates the no-slip boundary condition.

Nicole is working on this problem now through simulations. Nicole has helped draft a research proposal; she has developed a novel model using the MD simulation method and a math equation using a machine learning method. Her work has shown that 1) flow molecules next to the solid wall start with the wall velocity, but it slows down at a distance to the asperity contact tip and gradually reach full stop at the contact tip, and the change of velocity can be quantified as function of the distance to the asperity tip, 2) fluid density, the asperity wedge slope, and the strength of the fluid interaction with the border surface affect the range of the wall-slip region, and 3) an equation can be formulated to express the parameter correlation. She has recently presented her new findings at the 2024 STLE Annual Meeting and will further analyze how different lubricant molecules behave at the asperity tips.

Congratulations Nicole!