Prof. Berkin Dortdivanlioglu, Department of Civil, Architectural, and Environmental Engineering, Oden Institute for Computational Engineering and Sciences UT Austin

"Computational aspects of complex surface stresses in soft materials"

Abstract: To date, the mechanics of interfaces of soft solids, e.g., polymeric gels, remain elusive. Mechanical properties of the bulk gel can differ from those of the boundary due to the fundamental role of surface tension and other lowerdimensional energetics at small length scales. The energetic balance between surface and bulk deformations ascribes a physical length scale. A central challenge in understanding the behaviors of soft solids at small scales is elucidating the nonlinear effects due to complex surface stresses, e.g., viscous effects, curvature resistance, stiffening, and instability behavior. In this presentation, I will develop a 3D computational framework for modeling complex surface stresses and elucidate how they enrich the nonlinear solid-surface coupled deformation behavior. The developed size-dependent model proves to be useful in quantifying the surface and bulk energies in competition at highly nonlinear finite deformations. Extensions of this work toward hydrogels are promising in that surface and bulk can show distinctive mechanical, diffusional, and other multiphysical behaviors. The couplings between surface and bulk and the couplings between different fields can lead to a wide range of exciting properties and applications yet to be explored.