Focusing aspects of delayed Time Reversal based Nonlinear Elastic Wave Spectroscopy methods

Lints, Martin; Santos, Serge Dos; Salupere, Andrus

doi:10.1109/ultsym.2016.7728831

Cited by 1 publication

(2 citation statements)

References 34 publications

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“…The aforementioned linear acoustic methods have been successfully applied to detecting surface breaking cracks, but for contact damages (fatigue cracks, debondings, delaminations, etc.) they are not as sensitive as nonlinear elastic wave spectroscopy (NEWS) methods [28]- [30]. Experimental results demonstrate that the nonlinear effect of materials remarkably increases when the contact damages occur [31]- [35].…”

Section: Introductionmentioning

confidence: 99%

“…By combining the high sensitivity to defects of nonlinear acoustic and the self-focusing characteristic of the time-reversal (TR), many studies investigate novel methods to accurately detect contact damages without the need for accurate reference signals [54]. Two different integration schemes [55] are defined and well used: NEWS-TR, with nonlinear analysis as a pre-treatment of time-reversal; TR-NEWS, with nonlinear analysis as a post-treatment of traditional TR responses [30]. Many works demonstrated that compared with TR-NEWS, NEWS-TR shows significant improvements and effectiveness in diagnosing and localizing various types of contact damage in metal [56], [57], e.g.…”

Section: Introductionmentioning

confidence: 99%

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Detection of Surface Breaking Cracks Filled With Solid Impurities Using a Baseline-Free NEWS-TR Method

Qin

Zhang

et al. 2020

IEEE Access

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The use of piezoceramic transducers for cracks identification via guided wave has attracted significant attention recently. Most studies assume that the medium in surface breaking cracks is only air. However, it is common that such cracks are filled with impurities (e.g. dust, grease) due to its exposure to the operational environment. The impurities may affect the propagation of the ultrasonic guided wave and hence it is of practical interest to develop detection methods for surface breaking cracks filled with impurities. This work investigates the possible effect of contact acoustic nonlinearity (CAN) on detecting surface breaking cracks filled with solid impurities. A baseline-free method is proposed to detect surface breaking cracks filled with solid impurities using the nonlinear elastic wave spectroscopy (NEWS) as a pre-treatment of time-reversal (TR). This method involves three key issues: selecting low-frequency swept signal modulated by Hanning window as an excitation signal, comparing the initial filtered response with the nonlinear time reversal response to determine the nonlinear feature related to such cracks, and determining the recommended low cutoff frequency to extract such nonlinear feature. The feasibility of the proposed method is experimentally and numerically verified using aluminum beams with surface breaking cracks. Results show that due to the existence of solid impurities, the crack interacts with low-frequency ultrasonic waves, which leads to nonlinear components in the response signal. It also indicates that after the time-reversal processing, the shifting of the maximum peak frequency from the second harmonic range to the third harmonic range can be used as a damage-sensitive nonlinear feature for detecting such cracks. The proposed method provides a promising way to identify surface breaking cracks filled with solid impurities without reference signal. INDEX TERMS Baseline-free damage detection, contact acoustic nonlinearity (CAN), nonlinear elastic wave spectroscopy (NEWS), piezoelectric transducers, surface breaking cracks filled with solid impurities, structural health monitoring (SHM), time reversal (TR). GUOMING CHEN received the B.S. and M.S. degrees in petroleum mechanical engineering and the Ph.D. degree in mechanical design and theory from the

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Section: Introductionmentioning

confidence: 99%