An ultrasonic theoretical and experimental approach to determine thickness and wave speed in layered media

Sousa, Ana V. G.; Pereira, Wagner Coelho de Albuquerque; Machado, João Carlos

doi:10.1109/tuffc.2007.252

Cited by 10 publications

(5 citation statements)

References 23 publications

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“…Of the many available NDT techniques, ultrasonic measurements are the most widely accepted method for evaluating adhesive joints. [18][19][20] In De Sousa et al 20 study, a multilayered system was investigated to extract the layer thickness between acoustically dissimilar materials, and the authors found a typical error of less than 7% for their isotropic materials. In the present study, acoustically similar materials are utilized, a fiber-filled thermoset bonded with an unfilled thermoset, causing difficulty in signal interpretation.…”

Section: Introductionmentioning

confidence: 99%

“…Extensive studies have been conducted on various nondestructive testing (NDT) techniques to evaluate and analyze the adhesive bond quality. Of the many available NDT techniques, ultrasonic measurements are the most widely accepted method for evaluating adhesive joints 18–20 . In De Sousa et al 20 study, a multilayered system was investigated to extract the layer thickness between acoustically dissimilar materials, and the authors found a typical error of less than 7% for their isotropic materials.…”

Section: Introductionmentioning

confidence: 99%

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Automated bondline thickness quantification in adhesively joined composites and metals using ultrasound

Pulipati,

Kokkada Ravindranath,

Jack

2023

Polymer Composites

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The use of adhesively bonded joints between composite panels, metal panels, or between composites and metals are used in the aerospace and automotive industries to avoid stress concentrations due to fasteners while reducing weight. Quantifying the bond thickness allows for confidence that loading is being properly transferred. This study presents a methodology to measure bondline thickness using the data obtained from an immersion quality ultrasound scan using an out‐of‐tank, field‐portable, utlrasonic testing (UT) scanner. Eighteen bonded coupons were fabricated using a paste‐type adhesive filling a range of gaps between substrates of 0.254 and 1.27 mm. Three adhesively bonded coupon types were investigated: carbon fiber laminates, fiber glass laminates, and aluminum plates. A semiautomated algorithm is presented to quantify bondline thickness from the ultrasound data for each coupon type, generating a spatially varying 3D point cloud of adhesive thickness. Bondline measurements obtained using ultrasound are then validated over two orthogonal planes against measurements taken from x‐ray computed tomography reconstructions. Results indicate a typical accuracy of 0.081 mm for bondline thickness quantification for all samples studied, with the results from the inspection of the composite coupons yielding an error of 0.078 mm, whereas the accuracy when scanning the aluminum coupons yielded an error of 0.086 mm.Highlights Field‐portable, inspection station is presented for full waveform ultrasonics. Mathematical procedure to characterize adhesive bondline thickness. Results are presented for a variety of material systems and adhesive thicknesses. Results are validated against x‐ray computed tomography with a typical accuracy of 0.081 mm.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Automated bondline thickness quantification in adhesively joined composites and metals using ultrasound

Pulipati,

Kokkada Ravindranath,

Jack

2023

Polymer Composites

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“…Although it can be found a lot of techniques in literature for frequency dependent parameters measurement [1][2][3][4][5][6][7][8][9], Ping He's method [10][11][12][13] is one of the most used due to its ease and because it does not need any a priori knowledge of the material characteristics. Using simultaneous pulse-echo and through-transmission immersion measurements, it is able to provide the frequency dependent thickness and phase velocity.…”

Section: Introductionmentioning

confidence: 99%

Automatic simultaneous measurement of phase velocity and thickness in composite plates using iterative deconvolution

Rodríguez-Martínez

Svilainis

Dumbrava

et al. 2014

NDT & E International

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Svilainis, L.; V. Dumbrava; Dumbrava, V.; Salazar Afanador, A. (2014). Automatic simultaneous measurement of phase velocity and thickness in composite plates using iterative deconvolution. NDT and E International. 66:117-127. doi:10.1016/j.ndteint.2014 AbstractA new method for the automatic and simultaneous measurement of phase velocity and thickness for thin composite plates was developed based on Ping He's method, without any need of a priori knowledge of the material parameters. Two composites were analyzed: a block of clean epoxy and a thin specimen of glass-fiber reinforced plastic produced by Resin TransferMolding. The proposed method combines cross-correlation functions and iterative deconvolution for accurate measurement of times of flight and gating. The new method has demonstrated to be more accurate than conventional Ping He's method, and can be implemented automatically thus saving processing time and increasing accuracy.

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“…The algorithms discussed above make assumptions about the interrogated media, 11 lack resolution, 7,8,10 or become less accurate as the medium increases in complexity. 14 To handle more complex media with a less stringent assumption about the nature of the medium, a new method was recently proposed that is less affected by inhomogeneity and can find a localized sound speed measurement between arbitrary points within the influence of the transducer’s geometry.…”

mentioning

confidence: 99%

“…Greco de Sousa et al 11 have also recently presented a sound speed algorithm. Their algorithm’s intent is specifically to measure the sound speeds and thicknesses in multilayered media.…”

mentioning

confidence: 99%

A Method for Direct Localized Sound Speed Estimates Using Registered Virtual Detectors

2012

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Accurate sound speed estimates are desirable in a number of fields. In an effort to increase the spatial resolution of sound speed estimates, a new method is proposed for direct measurement of sound speed between arbitrary spatial locations. The method uses the sound speed estimator developed by Anderson and Trahey. Their least squares fit of the received waveform’s curvature provides an estimate of the wave’s point of origin. The point of origin and the delay profile calculated from the fit are used to arrive at a spatially registered virtual detector. Between a pair of registered virtual detectors, a spherical wave is propagated. By beamforming the data, the time-of-flight between the two virtual sources can be calculated. From this information, the local sound speed can be estimated. Validation of the estimator is made using phantom and simulation data. The set of test phantoms consisted of both homogeneous and inhomogeneous media. Several different inhomogeneous phantom configurations were used for the physical validation. The simulation validation focused on the limits of target depth and signal-to-noise ratio on virtual detector registration. The simulations also compare the impact of two- and three-layer inhomogeneous media. The phantom results varied based on signal-to-noise ratio and geometry. The results for all cases were generally less than 1% mean error and standard deviation. The simulation results varied somewhat with depth and F/#, but primarily, they varied with signal-to-noise ratio and geometry. With two-layer geometries, the algorithm has a worst-case spatial registration bias of 0.02%. With three-layer geometries, the axial registration error gets worse with a bias magnitude up to 2.1% but is otherwise relatively stable over depth. The stability over depth of the bias in a given medium still allows for accurate sound speed estimates with a mean relative error less than 0.2%.

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An ultrasonic theoretical and experimental approach to determine thickness and wave speed in layered media

Cited by 10 publications

References 23 publications

Automated bondline thickness quantification in adhesively joined composites and metals using ultrasound

Automated bondline thickness quantification in adhesively joined composites and metals using ultrasound

Automatic simultaneous measurement of phase velocity and thickness in composite plates using iterative deconvolution

A Method for Direct Localized Sound Speed Estimates Using Registered Virtual Detectors

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