Defect detection in thin plates by ultrasonic lamb wave techniques

Edalati, Kaveh; Kermani, A.; Seiedi, M.; Amir, Mohammad

doi:10.1504/ijmpt.2006.011268

Cited by 11 publications

(5 citation statements)

References 15 publications

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“…The behavior of Lamb waves generation and propagation and the transducer influence on such behavior, applying numerical methods and experimentation, was investigated [9]. Lamb wave emission experiments in aluminum plates proved that these high frequency waves were sensitive to damage presence, especially when small distances between damage and probe were considered [10]. Several of these experiments proved that more than one mode could be efficiently excited and applied in damage detection.…”

Section: Lamb Waves -Backgroundmentioning

confidence: 99%

Structural Health Monitoring System Using Piezoelectric Networks with Tuned Lamb Waves

Rocha

Silva

Suleman

2010

Shock and Vibration

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Abstract. The paper presents a structural health monitoring system based on propagation of tuned Lamb waves and their interference with discontinuities. The dispersion curves are studied to determine the appropriate type and dimension of transducers and to select the optimum scanning frequencies and relevant propagation modes. A piezoelectric sensor network was implemented in an aluminum plate in order to generate and to sense the wave propagation and associated reflections. The algorithm developed for damage detection relies on the comparison of undamaged and damaged responses of the structure. Combinations of filters and statistical methods were applied to detect differences in the sensor signals acquired for the two different states (damaged and undamaged), corresponding to damage reflections. In order to eliminate the false positives due to noise, a probability analysis is performed to obtain the final damage position. The software designed for the current application allows the automatic calculation of dispersion curves, it executes the scans, performs data processing, executes the detection algorithm and presents the probable damages and their positions in a graphical form. Experiments were performed with the introduction of cumulative damages in the plate such as surface and through-the-thickness holes and cuts, ranging from 7 mm to 1 mm in diameter. Additionally, a stringer was attached to the plate by a single rivet line to simulate an aircraft skin structure. Cuts originating from rivet holes and connecting adjacent rivets, as well as loosened rivets were detected by the system. The introduction of the stringer resulted in a loss of precision in the determination of the radial position of the damages near it. Also, the network revealed significant difficulties in the detection of damages beyond the stringer.

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Section: Lamb Waves -Backgroundmentioning

confidence: 99%

Structural Health Monitoring System Using Piezoelectric Networks with Tuned Lamb Waves

Rocha

Silva

Suleman

2010

Shock and Vibration

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“…In comparison to other UGW testing methods, Lamb wave testing is fast and more sensitive to the surface and internal defects over the thickness of the structure. [ 3 , 4 , 5 ]. Although UGW testing is an effective technique for the inspection of defects a few meters away from the transmitting transducers, defects may be located at longer distances [ 6 , 7 ].…”

Section: Introductionmentioning

confidence: 99%

2D Analytical Model for the Directivity Prediction of Ultrasonic Contact Type Transducers in the Generation of Guided Waves

Tiwari

Raišutis

Mažeika

et al. 2018

Sensors

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In this paper, a novel 2D analytical model based on the Huygens’s principle of wave propagation is proposed in order to predict the directivity patterns of contact type ultrasonic transducers in the generation of guided waves (GWs). The developed model is able to estimate the directivity patterns at any distance, at any excitation frequency and for any configuration and shape of the transducers with prior information of phase dispersive characteristics of the guided wave modes and the behavior of transducer. This, in turn, facilitates to choose the appropriate transducer or arrays of transducers, suitable guided wave modes and excitation frequency for the nondestructive testing (NDT) and structural health monitoring (SHM) applications. The model is demonstrated for P1-type macro-fiber composite (MFC) transducer glued on a 2 mm thick aluminum (Al) alloy plate. The directivity patterns of MFC transducer in the generation of fundamental guided Lamb modes (the S0 and A0) and shear horizontal mode (the SH0) are successfully obtained at 80 kHz, 5-period excitation signal. The results are verified using 3D finite element (FE) modelling and experimental investigation. The results obtained using the proposed model shows the good agreement with those obtained using numerical simulations and experimental analysis. The calculation time using the analytical model was significantly shorter as compared to the time spent in experimental analysis and FE numerical modelling.

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“…In paper [ 20 ], the detection and estimation of the cutting depth of artificial defects in a 2 mm thick metal plate is evaluated, using guided modes that are antisymmetric A 1 in pulse-echo and symmetric S 1 in pitch-catch, of a notch defect 0.5 mm wide and deep 10%, 30% and 60% of the plate thickness equal to 2 mm. Angled probes at a frequency of 2 MHz are used and the distance from the defect is approximately 75 mm, thus highlighting the importance of operating in a short-range condition.…”

Section: Analysis Of Scattering From Artificial Defects In Metal Lami...mentioning

confidence: 99%

Detection of a Submillimeter Notch-Type Defect at Multiple Orientations by a Lamb Wave A0 Mode at 550 kHz for Long-Range Structural Health Monitoring Applications

Capineri,

Taddei,

Marino Merlo

2024

Sensors

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The early detection of small cracks in large metal structures is a crucial requirement for the implementation of a structural health monitoring (SHM) system with a low transducers density. This work tackles the challenging problem of the early detection of submillimeter notch-type defects with a semielliptical shape and a groove at a constant width of 100 µm and 3 mm depth in a 4.1 mm thick aluminum plate. This defect is investigated with an ultrasonic guided wave (UGW) A0 mode at 550 kHz to investigate the long range in thick metal plates. The mode selection is obtained by interdigital transducers (IDTs) designed to operate with a 5 mm central wavelength. The novel contribution is the validation of the detection by pulse-echo and pitch and catch with UGW transducers to cover a distance up to 70 cm to reduce the transducers density. The analysis of scattering from this submillimeter defect at different orientations is carried out using simulations with a Finite Element Model (FEM). The detection of the defect is obtained by comparing the scattered signals from the defect with baseline signals of the pristine laminate. Finally, the paper shows that the simulated results are in good agreement with the experimental ones, demonstrating the possible implementation in an SHM system based on the efficient propagation of an antisymmetric mode by IDTs.

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Defect detection in thin plates by ultrasonic lamb wave techniques

Abstract: ABSTRACT

Cited by 11 publications

References 15 publications

Structural Health Monitoring System Using Piezoelectric Networks with Tuned Lamb Waves

Structural Health Monitoring System Using Piezoelectric Networks with Tuned Lamb Waves

2D Analytical Model for the Directivity Prediction of Ultrasonic Contact Type Transducers in the Generation of Guided Waves

Detection of a Submillimeter Notch-Type Defect at Multiple Orientations by a Lamb Wave A0 Mode at 550 kHz for Long-Range Structural Health Monitoring Applications

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