Structural health monitoring strategy for detection of interlaminar delamination in composite plates

Quaegebeur, Nicolas; Micheau, Philippe; Masson, Patrice; Maslouhi, A.

doi:10.1088/0964-1726/19/8/085005

Cited by 27 publications

(22 citation statements)

References 20 publications

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“…The A 0 mode and S 0 mode have respectively a group velocity of approximately 1000 m/s and 4500 m/s (Figure 7a) at low frequencies (non-dispersive region), which is in good agreement with the values expected from the literature [3,7,10,13,27,30]. However, higher velocities were expected according to the theoretical dispersion curves plotted in Figure 2.…”

supporting

confidence: 89%

“…These new generated modes can come from cracks or debonding or from structural discontinuity observed in C, I, or T shaped composite structures used in helicopter rotor blades, aircraft wings, or wind turbines [8][9][10]. Both A 0 and S 0 modes exhibit mode conversion to S 0 mode and A 0 mode respectively when interacting with a discontinuity [8,[11][12][13]. Lamb waves are used for SHM because they can inspect large structures in a short time, following their curvature.…”

Section: Introductionmentioning

confidence: 99%

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Damage Detection in a Composite T-Joint Using Guided Lamb Waves

et al. 2018

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Low velocity impact induces barely visible damage in the form of matrix cracking or delamination that can grow under hydro-thermo-mechanical loading and possibly lead to catastrophic failure if not detected at an early stage. A network of piezoelectric transducers can be used to monitor a structure over time for life prognosis through generation and sensing of guided ultrasonic waves. The aim of this study is to design and develop such a sensing method for damage assessment in a composite T-joint subjected to mechanical impacts. In this context, monitoring of Lamb waves in a carbon fibre reinforced polymer (CFRP) T-joint has been completed where dispersion and tuning curves have been obtained. Guided waves are transmitted into the structure through different specified pairs of surface-bonded lead-zirconate-titanate (PZT) transducers in a pitch-catch active structural health monitoring (SHM) approach. With these experiments, Lamb wave fundamental modes (A 0 and S 0 ) are identified for monitoring impact damage by signal comparison with a prior obtained baseline. Detecting 4J and 10J inner impacts within the central region of the specimen is challenging when using conventional non-destructive techniques (NDT) because of the complex geometry and interference with the web. Signals are compared for the same selected sensing path; and amplitude differences have been observed in tuning curves after the 10J impact, which implies the occurrence of a structural change related to the impact.

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confidence: 89%

Section: Introductionmentioning

confidence: 99%

Damage Detection in a Composite T-Joint Using Guided Lamb Waves

et al. 2018

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“…The transmitting PZT injected an impulse signal with a 2 μs duration into the specimen which was received by the opposite PZT. The Reassigned Short Time Fourier Transform (ReSTFT) algorithm was calculated from the receiving PZT signal to obtain the short-time experimental dispersion curves from the measured data as described by Niethammer and Jacobs [9] and Quaegebeur et al [10]. The theoretical dispersion curves were compared to the experimental results shown in Figure 2.…”

Section: Theoretical and Experimental Dispersion Curvesmentioning

confidence: 99%

“…The theoretical dispersion curves were compared to the experimental results shown in Figure 2. The A 0 mode can be followed on the experimental curves from theoretical calculations and thus an excitation frequency of 250 KHz was chosen such that a non-dispersive A 0 Lamb wave was injected and measured in the carbon fibre specimens for its known sensitivity to impact damage [10]. …”

Section: Theoretical and Experimental Dispersion Curvesmentioning

confidence: 99%

Assessment of PZT transducer bonding techniques under drop-weight impact loading in composites

et al. 2011

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This paper describes the robustness of a structural health monitoring system (SHM) that utilizes lead-zirconatetitanate (PZT) transducers tested on carbon fibre composite coupons under drop-weight impact loading. Four PZT transducers are attached to the surface of 10.16 cm x 15.24 cm aerospace grade carbon fibre coupons using four types of adhesives: cyanoacrylate, epoxy, methyl methacrylate, and silicon. Each PZT transducer is tuned to excite preferentially an A0 mode guided wave burst into each composite coupon prior to and following an impact. The output from a PZT transducer, the amplitude of the propagating guided waves measured using a laser vibrometer on the coupon surface and the RMS velocity is plotted. The cycle is repeated for the three remaining transducers. The electrical admittance is also measured using an impedance analyzer prior to and following impact. This paper illustrates how a robustness metric expressed in terms of admittance can be used to infer the ability of the SHM system to generate guided waves and to detect damage following impact. The robustness metric is a measure of the adhesive strength and the mechanism to provide accurate damage detection results. It is shown that transducers attached using silicon provide accurate damage detection results based on pre-attached adhesive yielding difference of <0.5% obtained from electrical admittance measurements before and after impact.

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“…1 Among the various techniques available, a SHM system based on Lamb wave propagation with piezoelectric transducers seems to be a cost-effective method for a quick and continuous inspection of thin-wall metallic 2 or composite structures. 3 Classically, sparse transducers arrays are mounted on the structure and interrogation is performed using Pitch and Catch 4 approach, electro-mechanical impedance changes 5 or Pulse-Echo measurements. 6 In order to minimize the footprint of sensors required for embedded damage detection, compact sensing strategies 7 have been proposed for pulse-echo configurations, with various array configurations.…”

Section: Introductionmentioning

confidence: 99%

A novel imaging technique for structural health monitoring using sparse and compact arrays

2011

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In the present paper, a technique called Excitelet is presented for the imaging of damages in thin-walled structures using the correlation of the measured signals with dispersed versions of the excitation signal. Piezoceramic (PZT) actuators are used to generate burst Lamb waves which interact with defects in metallic structures and the measurement is taken using sparse and compact array configurations of PZT sensors. The sparse sensing configuration consists of individual circular PZT elements distributed over the plate while the compact array configuration consists of a linear arrangement of sensors micro-machined on a single piece of bulk PZT wafer. This approach is presented as an extension of the classical imaging techniques and takes advantage of the chirplet-based matching pursuit algorithm. The approach is investigated experimentally on a 1.54 mm thick aluminum plate and comparison with existing Embedded Ultrasonic Structural Radar (EUSR) algorithm is performed for A0 and S0 modes for two frequency ranges of interest (centered at 150 kHz and 550 kHz). Damages are simulated using stacked magnets at different locations on the plate. Significant improvement of imaging quality is demonstrated with respect to existing imaging techniques based on group velocity and Time-of-Flight (ToF), for both sparse and compact PZT array configurations. Multimodal imaging strategies are presented to improve the imaging results. Moreover, it is shown that the proposed imaging technique provide accurate results in the case of dispersive propagation, while existing imaging techniques are no longer applicable.

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Structural health monitoring strategy for detection of interlaminar delamination in composite plates

Cited by 27 publications

References 20 publications

Damage Detection in a Composite T-Joint Using Guided Lamb Waves

Damage Detection in a Composite T-Joint Using Guided Lamb Waves

Assessment of PZT transducer bonding techniques under drop-weight impact loading in composites

A novel imaging technique for structural health monitoring using sparse and compact arrays

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