Multiscale Computational Modeling and Design of New Classes of Electroactive and Magnetoactive Materials

Since the turn of the millennium, driven by the advent of new synthesis and additive manu-facturing processes capable of delivering materials with highly controllable nano- and micro-structures, increasing efforts have been devoted to the investigation and design of advanced materials with unprecedented multifunctional properties. In this context, I will begin this talk by presenting two new classes of numerical methods capable to describe the macroscopic elec-tromechanical and magnetomechanical behaviors -- under arbitrarily large deformations, elec-tric fields, and magnetic fields -- of materials directly in terms of their (random or periodic) microstructure and microscopic behavior. The first method is based on a high-order WENO finite-difference scheme for Hamilton-Jacobi equations, while the second one is based on a conforming hybrid finite element discretization of Crouzeix-Raviart type. All the solutions generated by these methods share key functional features that lead in turn to a simple closed-form approximation for the coupled and nonlinear macroscopic response of these classes of materials.

By deploying the aforementioned methods, I will then present results that shed light on exper-imental findings on the response of emerging dielectric elastomer composites and magnetorhe-ological elastomers that had remained challenging to interpret for more than a decade. What is more, the results also suggest two new paradigms for the bottom-up design of materials with a myriad of extreme macroscopic behaviors: (i) the presence of interphasial space charges in di-electric elastomer composites to achieve deformable dielectrics with unusually large permittiv-ities and electrostriction coefficients as well as metamaterial-type behaviors featuring negative permittivities, and (ii), ferrofluid inclusions as superior fillers in lieu of the more conventional iron particle for magnetorheological elastomers with giant magnetostriction capabilities.

Victor Lefevre, PhD

Assistant Professor

Northwestern University