Complete noncontact laser ultrasonic imaging for automated crack visualization in a plate

An, Yun‐Kyu; Park, Byeongjin; Sohn, Hoon

doi:10.1088/0964-1726/22/2/025022

Cited by 156 publications

(99 citation statements)

References 27 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The energy of all the waves comprises the forward and backward wave energies and the standing wave energy. In the total wave energy, the forward and backward waves retain their forms with the additional term due to the standing wave energy and hence the only standing wave energy can be simply extracted by subtracting the forward and backward wave energies from the total wave energy [11]. The damage can then be identified by extracting the standing wave energy.…”

Section: Process For Damage Visualizationmentioning

confidence: 99%

Delamination Visualization in CFRP Laminated Concrete Structures Using Pulsed Laser-Based Ultrasonic Propagation Images

Lee¹,

Park²

2016

Proceedings of the 9th International Conference on Fracture Mechanics of Concrete and Concrete Structures

View full text Add to dashboard Cite

Abstract:One of the most critical characteristics of concrete structures is the brittleness of the concrete and hence the concrete is vulnerable to tension force. To overcome this drawback, the use of carbon-fiber-reinforced polymer (CFRP) sheets and/or plates laminated on the surface of concrete structures has increased. However, the efficiency of the CFRP reinforcement to endure the tension force is reduced when the CFRP sheets and/or plates are delaminated from the concrete structures due to external loads and impacts during service. This study presents the application of a pulsed laser scanned ultrasonic wave propagation imaging technique for detecting delamination damage of the CFRP laminated concrete structures. For the experimental studies, the delamination was artificially formed when the CFRP sheets were attached on the concrete structures and scanned using the Nd: YAG pulsed laser scanning system. By applying a frequency-wavenumber filtering algorithm to the wave responses measured from the Nd: YAG pulsed laser scanning system, flaw images of the delamination of the CFRP sheets were successfully obtained. This result confirmed the feasibility of the pulsed laser scanned ultrasonic wave propagation imaging technique to serve as an effective structural health monitoring system for actual CFRP laminated concrete structures.

show abstract

Section: Process For Damage Visualizationmentioning

confidence: 99%

Delamination Visualization in CFRP Laminated Concrete Structures Using Pulsed Laser-Based Ultrasonic Propagation Images

Lee¹,

Park²

2016

Proceedings of the 9th International Conference on Fracture Mechanics of Concrete and Concrete Structures

View full text Add to dashboard Cite

show abstract

“…System A complete noncontact laser ultrasonic system is used in this study for generation and sensing of ultrasonic waves [14]. As shown in …”

Section: Description Of a Noncontact Laser Ultrasonicmentioning

confidence: 99%

Fatigue Crack Localization Using Laser Nonlinear Wave Modulation Spectroscopy (LNWMS)

Li¹,

Sohn²,

Kundu³

2014

Journal of the Korean Society for Nondestructive Testing

Self Cite

View full text Add to dashboard Cite

Nonlinear features of ultrasonic waves are more sensitive to the presence of a fatigue crack than their linear counterparts are. For this reason, the use of nonlinear ultrasonic techniques to detect a fatigue crack at its early stage has been widely investigated. Of the different proposed techniques, laser nonlinear wave modulation spectroscopy (LNWMS) is unique because a pulse laser is used to exert a single broadband input and a noncontact measurement can be performed. Broadband excitation causes a nonlinear source to exhibit modulation at multiple spectral peaks owing to interactions among various input frequency components. A feature called maximum sideband peak count difference (MSPCD), which is extracted from the spectral plot, measures the degree of crackinduced material nonlinearity. First, the ratios of spectral peaks whose amplitudes are above a moving threshold to the total number of peaks are computed for spectral signals obtained from the pristine and the current state of a target structure. Then, the difference of these ratios are computed as a function of the moving threshold. Finally, the MSPCD is defined as the maximum difference between these ratios. The basic premise is that the MSPCD will increase as the nonlinearity of the material increases. This technique has been used successfully for localizing fatigue cracks in metallic plates.

show abstract

“…An alternative approach is to generate waves with a scanned laser and receive with either a fixed piezoelectric transducer or a fixed LDV; the waves appear to originate at the fixed receiver location due to reciprocity of transmission and reception for linear elastodynamic systems. These techniques are described and compared in [6]. Yet another relatively common means of obtaining wavefield data is the use of air-coupled transducers, which have the advantage of low cost (compared to laser equipment) and fast scan speeds, but have several disadvantages, mainly related to data quality because of the large impedance mismatch between air and the specimen under test [7,8].…”

Section: Introductionmentioning

confidence: 99%

“…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.…”

Section: Introductionmentioning

confidence: 99%

Ultrasonic wavefield imaging: Research tool or emerging NDE method?

Michaels¹

2017

AIP Conference Proceedings

View full text Add to dashboard Cite

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.

show abstract

Complete noncontact laser ultrasonic imaging for automated crack visualization in a plate

Cited by 156 publications

References 27 publications

Delamination Visualization in CFRP Laminated Concrete Structures Using Pulsed Laser-Based Ultrasonic Propagation Images

Delamination Visualization in CFRP Laminated Concrete Structures Using Pulsed Laser-Based Ultrasonic Propagation Images

Fatigue Crack Localization Using Laser Nonlinear Wave Modulation Spectroscopy (LNWMS)

Ultrasonic wavefield imaging: Research tool or emerging NDE method?

Contact Info

Product

Resources

About