Abstract:The continued and expanded use of composite materials in aerospace applications necessitates structural health monitoring and/or nondestructive evaluation techniques that can provide quantitative and detailed damage information for layered plate-like components (such as composite laminates). Guided wavefield methods are at the basis of a number of promising techniques for the detection and the characterization of damage in plate-like structures. Among the processing techniques that have been proposed for guide… Show more
“…Early efforts considered "snapshot" visualization [22] as well as accumulated energy plots [23]. Other approaches include standing wave analysis [6], wavenumber filtering [24], instantaneous wavenumber techniques [25][26][27], anomaly detection via dictionary learning [28], and a combined beamforming and wavenumber analysis technique [29], although this list is certainly not inclusive.…”
Multi-site delamination detection and quantification in composites through guided wave based global-local sensing AIP Conference Proceedings 1806, 020007 (2017) Abstract. Ultrasonic wavefield imaging refers to acquiring full waveform data over a region of interest for waves generated by a stationary source. Although various implementations of wavefield imaging have existed for many years, the widespread availability of laser Doppler vibrometers that can acquire signals in the high kHz and low MHz range has resulted in a rapid expansion of fundamental research utilizing full wavefield data. In addition, inspection methods based upon wavefield imaging have been proposed for standalone nondestructive evaluation (NDE) with most of these methods coming from the structural health monitoring (SHM) community and based upon guided waves. If transducers are already embedded in or mounted on the structure as part of an SHM system, then a wavefield-based inspection can potentially take place with very little required disassembly. A frequently-proposed paradigm for wavefield NDE is its application as a follow-up inspection method using embedded SHM transducers as guided wave sources if the in situ SHM system generates an alarm. Discussed here is the broad role of wavefield imaging as it relates to ultrasonic NDE, both as a research tool and as an emerging NDE method. Examples of current research are presented based upon both guided and bulk wavefield imaging in metals and composites, drawing primarily from the author's work. Progress towards wavefield NDE is discussed in the context of defect detection and characterization capabilities, scan times, data quality, and required data analysis. Recent research efforts are summarized that can potentially enable wavefield NDE.
“…Early efforts considered "snapshot" visualization [22] as well as accumulated energy plots [23]. Other approaches include standing wave analysis [6], wavenumber filtering [24], instantaneous wavenumber techniques [25][26][27], anomaly detection via dictionary learning [28], and a combined beamforming and wavenumber analysis technique [29], although this list is certainly not inclusive.…”
Multi-site delamination detection and quantification in composites through guided wave based global-local sensing AIP Conference Proceedings 1806, 020007 (2017) Abstract. Ultrasonic wavefield imaging refers to acquiring full waveform data over a region of interest for waves generated by a stationary source. Although various implementations of wavefield imaging have existed for many years, the widespread availability of laser Doppler vibrometers that can acquire signals in the high kHz and low MHz range has resulted in a rapid expansion of fundamental research utilizing full wavefield data. In addition, inspection methods based upon wavefield imaging have been proposed for standalone nondestructive evaluation (NDE) with most of these methods coming from the structural health monitoring (SHM) community and based upon guided waves. If transducers are already embedded in or mounted on the structure as part of an SHM system, then a wavefield-based inspection can potentially take place with very little required disassembly. A frequently-proposed paradigm for wavefield NDE is its application as a follow-up inspection method using embedded SHM transducers as guided wave sources if the in situ SHM system generates an alarm. Discussed here is the broad role of wavefield imaging as it relates to ultrasonic NDE, both as a research tool and as an emerging NDE method. Examples of current research are presented based upon both guided and bulk wavefield imaging in metals and composites, drawing primarily from the author's work. Progress towards wavefield NDE is discussed in the context of defect detection and characterization capabilities, scan times, data quality, and required data analysis. Recent research efforts are summarized that can potentially enable wavefield NDE.
“…In recent years, full time-space wavefields of guided waves, measured by non-contact laser Doppler vibrometers, have been extensively studied for use in damage detection [6][7][8][9][10][11][12]. The various methods developed to process full wavefield data for damage detection include: amplitude based imaging, wave filtering based imaging, and wavenumber based imaging, among others [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24]. Wavenumber based imaging uses intrinsic wavenumber information obtained from the full wavefields for quantitative evaluation of the defects in metals and laminated composites [18][19][20][21][22][23][24].…”
Section: Introductionmentioning
confidence: 99%
“…The various methods developed to process full wavefield data for damage detection include: amplitude based imaging, wave filtering based imaging, and wavenumber based imaging, among others [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24]. Wavenumber based imaging uses intrinsic wavenumber information obtained from the full wavefields for quantitative evaluation of the defects in metals and laminated composites [18][19][20][21][22][23][24]. It has been shown that wavenumber information can be used not only to detect the damage location, but also to quantify the damage size, shape and depth [18][19][20][21][22][23][24].…”
Abstract. This paper presents a guided wave based global-local sensing method for rapid detection and quantification of multi-site delamination damage in large composite panels. The global-local approach uses a hybrid system consisting of a piezoelectric transducer (PZT) for generating guided waves and a non-contact scanning laser Doppler vibrometer (SLDV) for acquiring guided wave data. The global-local method is performed in two steps. First, a phased array configured of a small number of SLDV scan points (for example 10×10 points in a rectangular grid array) performs inspection over the entire plate to detect and locate damage. Local areas are identified as potential damage regions for the second step. Then high density wavefield measurements are taken over the identified areas and wavefield analysis is performed to quantitatively evaluate the damage. For the proof of concept in case with multi-site damage, the global-local approach is demonstrated on a carbon fiber reinforced polymer (CFRP) composite plate with two sites of impact-induced delamination damage. In the first step, the locations of two delamination sites are detected by the phased array method. In the second step, the delamination size and shape are evaluated using wavefield analysis. The detected delamination location, size and shape agree well with those of ultrasonic C-scan and the method led to a 93% reduction in inspection time compared to a full SLDV dense grid scan.
“…These methods commonly address mapping flaws by recording the wave propagation over a finite span of the wavefield, rather than measurements at a single point. These methods reduce the wavefield through wavenumber filtering [11][12][13] to identify damage, or exploit changes in the propagating wave's characteristic over a delamination to locate the flaw [14,15].…”
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