P4G-3 An Efficient Measurement Strategy for Plate Wave Diffraction Tomography

Rohde, A.; Veidt, Martin

doi:10.1109/ultsym.2007.516

Cited by 3 publications

(2 citation statements)

References 10 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Based on the identified damage location in phase one, the damage characterisation image can then be generated using Lamb wave diffraction tomography [5][6] . Based on Mindlin plate theory and assuming the damage is a weak inhomogeneity occupying a finite region Σ , the scattering of a flexural wave can be approximated by Born approximation as 5…”

Section: Phase Two: Damage Characterisation Imagingmentioning

confidence: 99%

Integrated piezoceramic transducers for imaging damage in composite laminates

Veidt

Rajic

2009

SPIE Proceedings

Self Cite

View full text Add to dashboard Cite

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.

show abstract

Section: Phase Two: Damage Characterisation Imagingmentioning

confidence: 99%

Integrated piezoceramic transducers for imaging damage in composite laminates

Veidt

Rajic

2009

SPIE Proceedings

Self Cite

View full text Add to dashboard Cite

show abstract

“…Then the performance of PWDT has been demonstrated by imaging simple laminar damages in plate-like structures [19,141,143]. Based on the analytical framework in [41,140], Rose and Wang [17] further developed a ltered back-propagation (FBP) reconstruction formula and demonstrated its performance by imaging delamination damages of two dierent congurations.…”

Section: Introductionmentioning

confidence: 99%

Applications of diffraction tomography on quantitative imaging using ultrasonic guided plate waves

Su¹

View full text Add to dashboard Cite

Critical infrastructures in transport and civil engineering applications can suer from structural damages such as fatigue cracks and corrosion due to extreme loading or environmental conditions. Under the commonly used damage tolerant design philosophy, structures will not fail if damages are limited in size and severity. However, if damages are not detected at the early stage and properly controlled, they may grow in terms of their sizes and severities, which can eventually lead to catastrophic failures. Therefore, it is important to monitor the onset and progression of structural damages to ensure the safety of critical infrastructure assets.Structural health monitoring (SHM) technologies have shown potential to improve the management of key structural components. Among the possible SHM techniques, guided wave testing using piezoelectric transducers as transmitter and receiver elements is an attractive methodology, because it enables fast scanning of large areas. To assess the structural integrity, a quantitative imaging method is required. One of the methods that has attracted major attention is guided wave or plate wave diraction tomography (PWDT) because it enables quantitative characterization of damages including location, size as well as severity. Although the performance of PWDT has been demonstrated to characterize, for example remaining plate thickness for corrosion damages, its reliability and versatility using dierent system congurations have not yet been systematically evaluated.This thesis aims to evaluate the performance of PWDT, and to understand the underlying physical mechanisms aecting its performance. It also investigates the feasibility of extending PWDT to other fundamental plate wave modes beyond the rst exural wave mode. Hence, the three major objectives of the thesis are: i) to quantitatively identify the applicable range of PWDT for reliable and accurate damage reconstructions for dierent wave modes; ii) to understand the physical mechanisms that aect the performance of PWDT reconstruction; and iii) to investigate the feasibility of developing a baseline-free imaging technique by considering mode conversion eects in the framework of PWDT.To achieve this comprehensive and fundamental understanding of PWDT and systematically evaluate its imaging quality, its performance to image circular blind hole damages in isotropic plates is evaluated. This requires the calculation of the scatter elds corresponding to the three fundamental plate wave modes using analytical models and including all possible mode conversion eects. In the case of incoming and scattered fundamental exural waves the damage characteristics, including size and severity are accurately estimated as long as the fundamental i limitations of the imaging algorithm are fullled, i.e. Born approximation and diraction limit.Hence the accuracy is generally lower for larger and deeper defects. For the fundamental symmetric Lamb wave mode, the imaging quality is superior for large and severe damages.However, the quality of the i...

show abstract