Wave-based SHM of sandwich structures using cross-sectional waves

Abstract

Summary The identification of structural damage in composite waveguides is a critical issue in aerospace and transportation industries. Frequently, these structures involve periodic patterns or dissipative components that considerably reduce the range, robustness, and available bandwidth of ultrasonic structural health monitoring techniques. On the other hand, wave‐based methods provide more accurate information on a defect's type, size, and location than modal analysis techniques. This paper focuses on a low‐frequency wave‐based method for structural integrity assessment of complex waveguides. The wave finite element method is employed to compute the dispersion curves of non‐standard cross‐sectional waves exhibiting increased strain energy. The spectral results are used to analyse the diffusion of guided elastic waves through representative localized defects in a laminated sandwich panel. To validate the diffusion model, reflection and transmission coefficients are determined for several wave pulses on typical defects using time‐domain virtual experiments and cross‐sectional energy acquisition. Results demonstrate that using cross‐sectional waves provides a sensitivity to damage up to 2.8× higher than flexural waves in the low‐frequency range. These results are explained by the presence of local resonances within the cross section, producing wavelengths in the transverse direction of propagation. These waves may prove suitable for cost‐effective structural health monitoring applications because they can travel long distances through heterogeneous and periodic structures.

Simulation and detection of blockage in a pipe under mean fluid flow using acoustic wave propagation technique

“…The first positive peaks seen in each of the graphs indicate the arrival of the pressure pulse to the corresponding pressure monitoring location. The compression pulse subsequently propagates past the respective pressure monitoring locations s 1 ,s 2 ,s 3 ,s 4 ,s 5 , and s 6 . The first negative peaks shown at the various pressure monitoring locations are the times taken by the wave to travel to the pipe outlet and back to the corresponding pressure monitoring locations.…”

“…They concluded that the classification resolution can reach a much as more than 99% for road cutters and 95% for overall. Droz et al proposed a way of using high‐order cross‐sectional waves (CSW) to increase the sensitivity of a low‐frequency guided wave method for structural health monitoring (SHM). They conducted a diffusion analysis through three types of defects, and they show that waveguide's finite section can be used to exploit the reflection characteristics of CSW.…”

Generalized Gaussian smoothing for baseline‐free debonding assessment of sandwich panels

“…This has led to the development of damage detection methods based on different and ample varied nondestructive techniques. For example, some recent techniques are based on the use of guide waves, 2 solitary waves, 3 Lamb waves, 4,5 the change of the plate electromechanical impedance, 6 or the ultrasonic dispersive properties, 7 exploring the flexural 8 and cross-sectional waves 9 or applying thermographic analysis. [10][11][12][13] Additionally, a recent concern has arisen regarding the reliability of nondestructive techniques to sizing and locating damage; see, for instance, Aldrin et al, 14 where a regression analysis is proposed to address the issue.…”

Diffusion based homogenization method for 1D wave propagation

“…In this paper, a dynamic homogenization technique is developed that exploits WFEM framework in a CPA context to create an equivalent media in order to overcome these issues. In the proposed technique, the Diffusion Matrix Model (DMM) [22,23,24], which is an highly effective numerical technique to determine the local scattering properties of Bloch waves propagating through a FE-modelled interface, is used.…”