SMSD SEMINAR SERIES : Multiphysics Mechanics of Polymeric Gels
Thursday, September 19, 2019 at 4:00pm
Professor Shawn Chester, New Jersey Institute of Technology
Many new and exciting phenomena in mechanics are inherently multiphysics. A few examples include, thermally responsive shape-memory polymers, Joule heating causing creep, and pore pressure effects in geo-materials, to name just a few. Because so many technologically important phenomena are inherently multiphysics, constitutive models and associated simulation tools must also include all relevant physics to capture the primary features of the materials response to be predictive. In this talk, I will discuss recent and ongoing research on the multiphysics response of polymeric materials, specifically polymeric gels.
A gel is a polymeric material swollen by a fluid, and the fluid does not degrade or chemically modify the polymer network. The talk begins with recent experimental observations on the mechanical behavior of polymeric gels. Then a continuum level model for the coupled deformation-diffusion response of gels that incorporates anisotropy and inelasticity is summarized. That is followed by model calibration and attempts for validation on relatively simple gels. Results have shown that the behavior of polymeric gels is even more dependent on fluid uptake than previously thought.
Next, if time allows, the talk changes gears slightly and moves onto the topic of light activated polymer gels. The underlying mechanism that controls the swelling/deswelling in these materials is a photochemical reaction driven by UV irradiation. The light induced chemical reaction alters the configuration of photo-sensitive side groups, which in turn modifies the interaction between the polymer network and fluid. A continuum level model is proposed and a numerical capability overviewed that qualitatively describes the behavior of these materials.
Bio: Shawn Chester is currently an Associate Professor in Mechanical Engineering at the New Jersey Institute of Technology. Shawn was previously a postdoctoral researcher at Lawrence Livermore National Laboratory. Prior to that he obtained his PhD in solid mechanics from the Mechanical Engineering at MIT, and obtained both his BS and MS in Mechanical Engineering from NJIT.
Shawn's research focus in the past few years has been the development of experimentally validated continuum level constitutive theories for large-deformation multiphysics behavior of polymeric materials and the associated numerical implementation. His work spans most aspects of mechanics; experimental characterization, theoretical modeling, numerical implementation, and experimental validation. Shawn has been recognized by young investigator awards through an NSF CAREER, and an ASME award.