Elastomers filled with liquid inclusions: Theory, numerical implementation, and some basic results

Abstract:

Over the past few years, a series of experimental and theoretical investigations have pointed to elastomers filled with liquid inclusions -- ranging from ionic liquids, to liquid metals, to ferrofluids -- as a promising new class of materials with unique combinations of mechanical and physical properties. The reason behind such novel properties is twofold. On one hand, the addition of liquid inclusions to elastomers increases the overall deformability. This is in contrast to the addition of conventional fillers, which, being typically made of stiff solids, decreases deformability. On the other hand, the mechanics and physics of the interfaces separating a solid elastomer from embedded liquid inclusions, while negligible when the inclusions are ''large'', may have a significant and even dominant impact on the macroscopic response of the material when the inclusions are ''small''.

In this talk, I will present a general continuum framework and associated numerical implementation that describes the macroscopic mechanical behavior of elastomers filled with liquid inclusions directly in terms of their microscopic behavior. The focus will be on the non-dissipative case when the elastomer is a hyperelastic solid, the liquid making up the inclusions is a hyperelastic fluid, the interfaces separating the solid elastomer from the liquid inclusions feature their own hyperelastic behavior, which may possibly include the presence of initial interfacial forces such as surface tension, and the inclusions are initially spherical in shape. Within this case, in particular, I will present results for random isotropic suspensions of monodisperse liquid spherical inclusions and discuss their unique mechanical properties.

Bio:

Oscar Lopez-Pamies is the Colonel Harry F. & Frankie M. Lovell Professor in the Department of Civil and Environmental Engineering at the University of Illinois Urbana-Champaign, which he joined in 2011. He received his B.A. degree in Mathematics and B.S. and M.S. degrees in Mechanical Engineering from the University of Maryland Baltimore County in 2001 and 2002, and his Ph.D. degrees in Applied Mechanics from the University of Pennsylvania and Ecole Polytechnique (France) in 2006. His research focuses on the development of mathematical theories and associated numerical methods to describe, explain, and predict the mechanical and physical behavior, stability, and failure of highly deformable heterogeneous solids. He is the recipient of a number of academic honors, including the Young Scientist Prize from the European Mechanics Society in 2009, the NSF CAREER award in 2011, the Journal of Applied Mechanics award in 2014, and the Young Investigator Medal from the Society of Engineering Science in 2017.