A new power-based method to determine the first arrival information of an acoustic emission wave

Abstract

Acoustic emission is a powerful experimental structural health monitoring technique for determining the location of cracks formed in a member. Pinpointing wave arrival time is essential for accurate source location. Conventional arrival detection technique’s accuracy deteriorates rapidly in low signal to noise ratio (5–40 dB) region, thus unsuitable for source location due to this inaccuracy. A new technique to pinpoint the arrival time based on the power of the wave is proposed. We have designed an adaptive filter based on the power characteristics of acoustic emission wave. After filtration of the acoustic emission wave, sliding window is employed to accurately identify the region of wave arrival based on the change in transmitted power. The results from various experimental and numerical arrival time detection experiments consistently show that the proposed methodology is stable and accurate for a wide range of signal to noise ratio values (5–100 dB). Particularly, in signal to noise ratio region (5–40 dB), the method is significantly more accurate as compared to the other methods described in the literature. The method was then employed to study the localized damage progression in a steel fiber–reinforced beam under four-point bending. The results suggest that calculated source location using the new method is consistent with that from visual inspection of the member at failure and more accurate than the localization results from existing method.

A new non-linear framework for localization of acoustic sources

“…Once the source and sensor locations are known, the TOA can be calculated from the numerical simulation, which accounts for various physical phenomena such as dispersion, energy loss through absorption using any TOA detection methodology. 16,33,34 A simple alternative to obtain the TOA is the ray tracing method, but its accuracy needs to be checked. Using the same slowness field and Cartesian grid, the TOA calculated from the numerical method and ray tracing method (using equation (14)) are found to be the same.…”

“…A positive correlation exists between accuracy of detection accuracy of TOA and SNR of AE signal. 16,33 In other words, the accuracy in TOA detection would be high if SNR value is high conversely if SNR value is low. 16 To accurately introduce such error in TOA calculated from equation (14), we have added a random TOA error between the range µ ± 2 σ .…”

“…16,33 In other words, the accuracy in TOA detection would be high if SNR value is high conversely if SNR value is low. 16 To accurately introduce such error in TOA calculated from equation (14), we have added a random TOA error between the range µ ± 2 σ . Here, the average error µ is taken to be 18 sample points (with each point representing a difference of 0.2 µs on the time history of a wave), while the standard deviation of the error ( σ ) is taken to be 26 sample points.…”

“…Various factors, such as the use of adequate sensors, appropriate sensor configuration, environmental noise, accurate detection of arrival time, 16 relative orientation of source and sensors, source mechanism, and material inhomogeneity, 17,18 significantly affect stable and accurate source localization. Specifically, it is highly desirable to have a source location method that can effectively manage errors.…”

Impact Localization in Composites Using Time Reversal, Embedded PZT Transducers, and Topological Algorithms

“…However, TOA-based techniques require a relatively large number of receiver transducers measuring the coherent part of the wave field (ballistic wave). Advanced signal processing methods such as peak detection (Castro et al, 2018;Das and Leung, 2018;Zhou et al, 2019), cross-correlation (Kim et al, 2015;Li et al, 2018), Hilbert (Chen et al, 2018;Kim and Yuan, 2018), and wavelet transformation (Bianchi et al, 2015;Zhu et al, 2017) have been employed to extract physical parameters from measured data in order detect AE waves. Nevertheless, the dispersive nature of guided waves, as well as boundary reflections and mode conversion in geometrically complex components can all alter the acquired signal resulting in incorrect TOA estimations (Ciampa and Meo, 2011).…”