Benjamin Vial from Imperial College London will give a seminar for the « Electromagnetic Modeling » theme entilted « Quasi-Normal Modes for Elastic Wave Manipulation in Thin Plates » on Friday January 17th 2025 at 10h30 in Pierre Cotton’s room.
Abstract : In our latest work, we explore how we can better control elastic waves using large arrays of resonators, a key challenge in modern wave manipulation. To tackle this, we use a framework based on quasi-normal modes (QNMs), focusing on thin elastic plates. Using the well-established Green’s function formalism, we address multiple scattering
problems and develop a dispersive QNM expansion. This creates a reduced-order model that simplifies forced response computations while offering deeper physical insights into resonant mode excitation.
I will present this framework and also the derivation of sensitivities (i.e. how eigenvalues change with resonator parameters) and their use with gradient-based optimization to design quasi-bound states in the continuum and precisely tune eigenfrequencies in the complex plane. Simulations of structures like graded line arrays and quasi-crystals validate these methods. Inspired by QNM concepts in electromagnetism, this work demonstrates new possibilities for tailoring elastic wave behaviour, paving the way for advances in elastic metamaterials.
