The Biot-Allard poro-elasticity system: equivalent forms and well-posedness
Jakob S. Stokke, Markus Bause, Nils Margenberg, Florin A. Radu
TL;DR
The paper addresses poroelasticity with memory (the Biot--Allard model) by converting the convolution-based memory term into an auxiliary differential equation (ADE) framework through a frequency-domain series approximation of the dynamic permeability. It proves well-posedness within the abstract Picard framework for evolutionary problems, first for a single ADE and then generalizing to an $N$-pole expansion, establishing per-term positivity conditions that ensure stability. This convolution-free reformulation yields a coupled first-order evolutionary system that preserves memory effects while enabling efficient time-domain numerical schemes. The approach promises reduced memory requirements and faster simulations for dynamic poroelastic problems across geophysical and bio-mechanical contexts.
Abstract
We consider the fully dynamic Biot-Allard model, which includes memory effects. Convolution integrals in time model the history of the porous medium. We use a series representation of the dynamic permeability in the frequency domain to rewrite the equations in a coupled system without convolution integrals, suitable for the design of efficient numerical approximation schemes. The main result is the well-posedness of the system, proved by the abstract theory of R. Picard for evolutionary problems.
