Integrated piezoceramic transducers for imaging damage in composite laminates

Abstract

This paper presents a two-phase imaging methodology to characterise damage in composite laminates utilising Lamb waves generated by integrated piezoceramic transducers. The proposed methodology uses the transducers to sequentially scan the composite laminates before and after the presence of damage by transmitting and receiving Lamb wave pulses. In phase one the damage localisation image is reconstructed by analysing the cross-correlation of the wavelet extracted information from scatter signals with the excitation pulse for each transducer pair. A potential damage area is then reconstructed by superimposing the image observed from each actuator and sensor signal path. In phase two Lamb wave diffraction tomography is used to reconstruct an image quantifying size and shape of the damage based on the same set of measurement data and identified damage location in phase one. The two-phase imaging approach together with the modified diffraction tomography reconstruction algorithm enables a significant reduction of the required number of transducers without the need to know the damage location in advance. Numerical and experimental results are presented to demonstrate the efficiency, accuracy and sensitivity of the proposed methodology.

Analytical and finite element prediction of Lamb wave scattering at delaminations in quasi-isotropic composite laminates

“…Following earlier investigations [13,15,[22][23][24][25], the A 0 Lamb wave is the focus in this study because of its sensitivity to small defects due to its shorter wavelength compared to S 0 and SH 0 Lamb waves at the same excitation frequency.…”

“…Different techniques [5][6][7][8] have been developed to ensure the safety and reduce maintenance costs of structures. Guided waves (GWs) have demonstrated great potential for damage detection in a wide range of structural elements, including beams [9], pipes [10], metallic plates [11], and, more recently, composite laminates [12][13][14][15].…”

On Accuracy of Analytical Modeling of Lamb Wave Scattering at Delaminations in Multilayered Isotropic Plates

“…A variety of research has been conducted in an effort to improve the understanding of Lamb wave propagation and scattering at defects [5][6][7][8][9][10][11][12] , and to develop innovative techniques for safety inspection of layered materials, such as adhesive and diffusion bonded isotropic plates [13][14][15] and composite laminates 16,17 . Among the developed damage inspection techniques, Lamb wave diffraction tomography (LWDT) 18,19 is proving attractive as it is not only able to determine the existence and location of defects, but can also provide quantitative information from the damage inspection, such as defect sizes and shapes. Recently a generic diffraction tomography framework was proposed for imaging damage in plates 20 .…”

A two-stage approach for quantitative damage imaging in metallic plates using Lamb waves

“…For the proposed method, the continuous Gabor wavelet transform is employed to enhance the accuracy of the cross-correlation analysis. Hence, the crosscorrelation C ab is defined as (Ng et al 2009b)…”

“…WT F is the wavelet coefficient of the excitation pulse at the excitation frequency. These wavelet coefficients can be calculated by continuous Gabor wavelet transform (Kishimoto et al 1995, Ng et al 2009b as…”