MAE Seminar – Fluid-mediated Impact of Soft Solids

Details

Dear Undergraduate and Graduate Students, Faculty, and Staff,
You are invited! UF Department of Mechanical and Aerospace Engineering’s Seminar Series
This is a perfect opportunity to enjoy some coffee, cookies, and captivating talks! These sessions feature amazing guest speakers, from academic trailblazers and industry movers to our very own faculty candidates showing off their expertise and fresh perspectives.
Come for the treats, stay for the engaging discussions, and connect with fellow MAE enthusiasts. Everyone is welcome!

Fluid-mediated Impact of Soft Solids

October 9, 2025, at 12:50pm
Location: MAE-A 303

Dr. Antonio Joaquin Garcia Suarez
Scientist
Computational Solid Mechanics Laboratory

Abstract
A viscous, lubrication-like response can be triggered in a thin film of fluid squeezed between a rigid and flat surface and the tip of an incoming projectile. In this talk, I will present a comprehensive theory for this viscous approach stage of fluid-mediated normal impact, applicable to soft impactors. Under the assumption of mediating fluid being incompressible, the impacting solid displays two limit regimes: one dominated by elasticity and the other by inertia. The transition between the two is predicted by a dimensionless parameter, which can be interpreted as the ratio between two time scales that are the time that it takes for the surface waves to warn the leading edge of the impactor of the forthcoming impact, and the characteristic duration of the final viscous phase of the approach. Additionally, I will assess the role of solid compressibility and elucidate why nearly-incompressible solids feature (a) substantial “gliding” prior to contact at the transition between regimes, (b) the largest size of entrapped bubble between the deformed tip of the impactor and the flat surface, and (c) a sudden drop in entrapped bubble radius past the transition between regimes. Finally, I will argue that the above time scale ratio (a dimensionless number) can govern the different dynamics reported experimentally for droplets. These results are directly relevant to applications ranging from hydrogel and capsule delivery to bioprinting, protective coatings, and soft robotics.

Biography
Joaquin earned his engineering diploma from University of Seville in 2013 and a PhD in Aeronautics (minor in Applied Mathematics) from the California Institute of Technology in 2020, then joined Prof. Molinari’s group at EPFL, Lausanne, Switzerland, as a postdoc in 2021. In 2023, he was awarded a Swiss National Science Foundation (SNSF) Ambizione Fellowship (PI status, project funding CHF 830k~US $1M), to conduct independent research (with supervised graduate students) at EPFL on data-driven models for friction.

MAE Faculty Host: Dr. Ghatu Subhash