Lamb Wave Wireless Communication Through Healthy and Damaged Channels With Symmetrical and Asymmetrical Steps and Notches.

Data transmission through solid metallic channels is recommended in certain industries where no other options are proposed, such as nuclear, aerospace, and smart vehicles. In addition to the Faraday shielding effect of electromagnetic waves, another issue related to damage presence due to mechanical loads exists. Severe damage in the transmission channel leads to signal loss at the receiver.

Semi-analytical discontinuous Galerkin finite element method for the calculation of dispersion properties of guided waves in plates.

The development of reliable guided waves inspection systems is conditioned by an accurate knowledge of their dispersive properties. The semi-analytical finite element method has been proven to be very practical for modeling wave propagation in arbitrary cross-section waveguides. However, when it comes to computations on complex geometries to a given accuracy, it still has a major drawback: the high consumption of resources.

Reverberation of flexural waves scattered by a local heterogeneity in a plate.

A statistical model is proposed to relate the scattering properties of a local heterogeneity in a plate to the statistical properties of scattered and reverberated flexural waves. The contribution of the heterogeneity is isolated through the computation of differential signals consisting of a subtraction of the signals recorded after and before introduction of the heterogeneity. The theoretical expression of the average reverberation envelope of these differential signals is obtained as a function of the scattering cross-section of the heterogeneity.

Experimental study of passive defect localization in plates using ambient noise.

Passive listening methodology has been shown to be a practical and effective method for passive structural health monitoring. In this work, this approach is applied experimentally to monitor the occurrence of defects in thin aluminum plates. A correlation matrix is estimated from noise vibrations recorded on a transducer array.

Extraction of statistical properties of the point source response of a reverberant plate and application to parameter estimation (L).

The point source response of a reverberant solid plate is modeled through a nonstationary Poisson process based on the image-source method. The theoretical expectation of the envelope is then derived, taking into account the dispersive nature of plate waves, and validated by numerical results. Least-square curve-fitting applied to an ensemble average over N realizations can then be used to identify useful parameters such as wave velocity, plate surface, or source-receiver distance.

Modeling a surface-mounted Lamb wave emission-reception system: applications to structural health monitoring.

The work described in this paper is intended to present a simple and efficient way of modeling a full Lamb wave emission and reception system. The emitter behavior and the Lamb wave generation are predicted using a two-dimensional (2D) hybrid finite element-normal mode expansion model. Then the receiver electrical response is obtained from a finite element computation with prescribed displacements.

Experimental study of the A0 and S0 Lamb waves interaction with symmetrical notches.

The aim of this work is to study the fundamental Lamb modes interaction with defects in isotropic plates. For these experimental investigations, symmetrical notches with various depths milled in aluminum plates are considered. Moreover, the incident Lamb wave of a specific mode is generated by means of two identical thin piezoceramic transducers placed at the opposite sides of the plate.

Design of optimal configuration for generating A0 Lamb mode in a composite plate using piezoceramic transducers.

This work concerned a technique for a health monitoring system based on the generation and sensing of Lamb waves in composite structures by thin surface-bonded piezoceramic transducers. The objective was to develop transducers that are adapted for the damage detection in orthotropic composites. The key problem with the investigated Lamb waves was to select a mode to be sensitive to the damage.