Prediction of frequency and spatially dependent attenuation of guided waves propagating in mounted and unmounted A380 parts made up of anisotropic viscoelastic composite laminates

Abstract

Monitoring damage in composite structures using guided wave-based techniques is particularly effective due to their excellent ability to propagate over relatively long distance and hence to cover a large area with few testing time and equipment. The industrialization of this method is highly tributary of the number and placement of the active elements. Yet, the optimal sensorization of a structure relies on the decrease in amplitude of guided waves over propagation distance. A reliable prediction of attenuation of guided waves is still a challenge especially for anisotropic viscoelastic composite materials which exhibit complex changes of attenuation with propagation direction and thus a spatial dependency of attenuation. In this paper, the damped global matrix method (dGMM), having stable and efficient merits, is developed to predict the frequency and spatially dependent attenuation of waves propagating in anisotropic composite materials. dGMM integrates three damping models (Hysteretic, Kelvin-Voigt, and Biot models) into the conventional undamped GMM to consider viscoelasticity of composite laminates. The proposed dGMM is first theoretically validated by numerical comparison with the semi-analytical finite element method. In addition, two industrial case studies, parts of an A380 nacelle at scale one, are employed to experimentally validate the proposed attenuation prediction method. The first one is a fan cowl structure and the second one is an inner fixed structure, both either unmounted or mounted on an actual instrumented A380 plane. This makes the validation extremely valuable for both the scientific and industrial communities. The proposed attenuation prediction method thus paves the way to optimally deploy sensor network for structural health monitoring of anisotropic viscoelastic composite structures.

Cross-structures Deep Transfer Learning through Kantorovich potentials for Lamb Waves based Structural Health Monitoring.

“…The reversibility of the piezoelectric effect allows using the patches alternatively as sensors or actuators. LWs propagate at high velocity with low attenuation in thin layers [2][3][4], thus an inspection of large parts can be achieved with a relatively low number of PZTs and very rapidly. However, LWs propagation in the host structure is hard to analyze: several symmetric and antisymmetric modes can propagate simultaneously in the composite structures at the same frequency, LWs interact with the interfaces, they reflect on the borders, etc.…”

Guided waves propagation in arbitrarily stacked composite laminates: Between-layers incompatibility issue resolution using hybrid matrix strategy

“…10 Multi-layered sandwich plate is generally made up of arbitrarily oriented CFRP skins and aluminum alloy honeycomb core, where the core layer is considered as isotropic material. For instance, the IFS plate of A380 nacelle in [60] having stacking angles [0/-45/45/0/Al/0/45/-45/0]. For such a complex structure, when 𝜃 = 0 • , both the honeycomb core and the 0 • CFRP layers should be handled with HMS.…”

Topological Data Analysis for Lamb Waves Based SHM Method in Operational Conditions

“…These information about the health of the structure are the first step to computed an estimated Remaining Useful Life (RUL) [1] and to predict maintenance processes needs [2] . Current and previous works show the efficiency of frequency analysis to resolve SHM problems [1,2,3,4] . These methods use physical understanding of the behavior of the structure.…”