Physical Investigation on Robust Algorithms for Inverse Problems of Heterogeneous Metastructures

A typical inverse problem, identifying the wavespace for metastructures from measurements of displacement fields, is crucial to understanding the dynamic properties of metastructures and the optimal design of vibroacoustic performance. The validity examination of inverse methods for heterogeneous metastructures is still an open question, especially for those showing wave coupling effects. The present study examines the robustness and accuracy of different inverse methods for extracting the complex wavespace. We compare the nonlinear Inhomogeneous Wave Correlation (IWC) method and its extension, the Green’s Function Correlation (GFC) framework, with the linear Algebraic Wavenumber Identification (AWI) framework. Direct wave-based methodologies are employed to assess both the precision of these techniques and the influence of wave coupling on the inverse methods’ robustness. The study starts by evaluating the precision of all methods through Highly Contrasted Dissipative Structures (HCDS) with rheological viscoelastic material. Then, the limitation of GFC due to the assumption of the elastic formulation is demonstrated by the sandwich plate with thick soft cores.