A DCAMM seminar will be presented by
Professor Lorenzo Bardella
Department of Civil, Environmental, Architectural Engineering and Mathematics
University of Brescia, Italy
Abstract:
Ionic polymer metal composites (IPMCs) consist of an electroactive polymeric membrane plated with metal electrodes and including a fluid phase, constituted by ions dispersed in a solvent, whose motion allows for actuation and sensing applications.
Here, the IPMC behaviour is studied through a finite-deformation electrochemo-poromechanical theory that couples the linear momentum balance, the mass balances of solvent and mobile ions, and the Gauss law. This provides the capability to model peculiar IPMC features, such as the back-relaxation in actuation and the discharge under a sustained mechanical stimulus in short-circuit sensing, both phenomena being aided by the cross-diffusion of solvent and ions. The proposed formulation, with respect to other recent efforts, abandons the assumption that the fluid phase is a dilute solution, leading to significant benefits on both the modelling and the computation.
A reliable finite element (FE) implementation of theories suitable to capture the IPMC multiphysics is particularly challenging because the IPMC behaviour is governed by boundary layers (BLs) occurring in very thin membrane regions adjacent to the electrodes, where steep gradients of ion and solvent concentrations occur. To address this issue, the generalized FE (GFE) method is adopted to discretise the BLs. The GFE implementation allows both the application of large external actions compatible with experiments (e.g., up to 3 V drop across the electrodes in actuation) and the achievement of accurate predictions in a reasonable computational time.
Finally, the modelling of some experimental results from the literature demonstrates the potential of the proposed theory to be an effective tool for the thorough analysis and design of IPMCs.
Danish pastry, coffee and tea will be served 15 minutes before the seminar starts.
All interested persons are invited