Multiphysics modelling of advanced multifunctional porous materials for sustainable energy applications

Urgent challenges are posed by climate change in today’s world. Extreme weather conditions, such as floods, wildfires, and droughts, are among the most devastating consequences of global warming, and their frequency and intensity are increasing. This situation underscores the pressing need for a rapid transition toward sustainable energy systems and climate friendly engineering choices. The present dissertation spans through different topics across three climate-relevant porous-media systems. The first consider salt rocks, where the viscoelastic behavior in coupled hydro-mechanical settings is investigated, using both standard and fractional viscoelasticity, with motivation drawn from underground energy storage. The second focuses on Proton Exchange Membrane Water Electrolyzers (PEMWE), where a fully coupled electro-chemo-hydro-mechanical (ECHM) model of catalyst layers and membranes is developed to better understand degradation mechanisms and improve hydrogen production. The third concerns metal foams, examining finite-strain plasticity of open-cell/closed-cell structures under coupled hydro-mechanical loading, linking microstructure to macroscopic response. Building on this, the present work provides a modelling framework capable of capturing the complex multi-physics electro-chemical-hydro-mechanical processes involved in such applications. It relies on the Theory of Porous Media (TPM), to establish a continuum-based approach suitable for the efficient simulation of the coupled interactions in porous multiphase materials. This macroscopic perspective enables the accurate representation of the local interactions among the immiscible phases, as well as the application of Theory of Mixture for the miscible ones. The phenomena accounted for include solid deformation, water transport, nanopore pressure dynamics, proton diffusion, gas distribution and chemical reactions, all of which are essential for the functionality of the modern sustainable systems. Finally numerical simulations in two- and three-dimensional domains are presented to verify the capabilities of the model and to address key numerical stability challenges of the strongly coupled problems. The numerical implementations are carried out using the open-access finite element package FEniCSx, the well-known commercial software ABAQUS via suitable UMAT subroutines and Matlab scripts.