Periodic Reporting for period 1 - WIDEA (Wave-based Inspection for Damage Evaluation in structurally-Advanced composites)
Période du rapport: 2019-06-01 au 2021-05-31
Guided waves are one of the most efficient techniques for Structural Health Monitoring (SHM) in large-scale or slender structures, as they provide damage detection, localization and characterization capabilities across a broad range of structures and materials. Progress in the field has a direct impact on EU transportation, aerospace and offshore industries, where safety is crucial given the potential human, economic or environmental consequences of failures. Despite some encouraging applications to lightweight structures, the implementation of vibration- or wave-based SHM strategies in advanced structures remains challenging. Indeed, in order to combine high stiffness-to-weight ratio with low vibro-acoustic signatures these structures frequently involve composites, dissipative materials or periodic patterns to produce desirable response within targeted bandwidths. These new lightweight designs, metamaterials, or meta-structures also produce more complex propagative behaviors, such as mode conversions or Bragg resonances, which result in highly scattering waves and increased noise-to-signal ratios. This project aims to develop the numerical framework and physical models able to support model-based SHM and guided wave testing solutions in complex media such as acoustic metamaterials and large-scale periodic structures.
A unified numerical framework has been developed to model the dynamic or transient behavior of piecewise periodic structures involving multiple interfaces, loads or coupling regions. The formulation is compatible with different physics (elastic, acoustic, piezoelectric) and can be used to compute the various relevant indicators, including wave dispersion characteristics, dynamic responses, damage or interface scattering coefficients and energy flows. Propagation and interface diffusion phenomena have been investigated in different topologies of lightweight structures and enriched materials for the definition of wave control and scattering features identification strategies. A numerical framework was proposed for the calculation of wave diffusion maps in damaged waveguides with multiple random inclusions. A transient multi-scale reduction method was developed to tackle Guided Wave Testing problems with non-linear interfaces and conduct time-domain virtual testing for the SHM of periodic metamaterials. A diffusion analysis method was proposed to achieve the identification of damage scattering features, allowing a fast quantification of parametrized coupling interfaces. Results have been published in top journals and conferences of the field and resulted in several scientific distinctions including a major science and engineering award.
The project made a step forward for generating fast virtual datasets in the context of physics-based Guided Wave Testing techniques, with a particular emphasis on metamaterials and periodic assemblies. The proposed modelling framework is able to combine the computational benefits of periodic structure theory with a multi-scale model order reduction strategy and the advantages of a transient modelling approach, hence is highly compatible with non-linear simulations, virtual sensing and real-time digital twin and Structural Health Monitoring. The research developments on wave propagation models for meta-structures and enriched media has shed new lights on the possibilities offered by meso-architectural tailoring, both in terms of vibro-acoustic performances’ control and its drawbacks for model-based structural assessment. Furthermore, the project has contributed to popularize wave-based sub-structuring strategies as a remarkably efficient modelling tool for piecewise periodic structures in the vibro-acoustic and structural health monitoring scientific communities.