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| Naji, M. |
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| Motta, Antonella |
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| Aletan, Dirar |
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| Mohamed, Tarek |
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| Ertürk, Emre |
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| Taccardi, Nicola |
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| Kononenko, Denys |
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| Petrov, R. H. | Madrid |
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| Alshaaer, Mazen | Brussels |
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| Bih, L. |
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| Casati, R. |
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| Muller, Hermance |
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| Kočí, Jan | Prague |
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| Šuljagić, Marija |
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| Kalteremidou, Kalliopi-Artemi | Brussels |
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| Azam, Siraj |
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| Ospanova, Alyiya |
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| Blanpain, Bart |
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| Ali, M. A. |
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| Popa, V. |
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| Rančić, M. |
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| Ollier, Nadège |
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| Azevedo, Nuno Monteiro |
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| Landes, Michael |
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| Rignanese, Gian-Marco |
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Schagerl, Martin
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Topics
Publications (12/12 displayed)
- 2024Damage monitoring of pinned hybrid composite–titanium joints using direct current electrical resistance measurementcitations
- 2024Simultaneous laser ultrasonic measurement of sound velocities and thickness of plates using combined mode local acoustic spectroscopycitations
- 2023Composite Structures / Local residual random forest classifier for strain-based damage detection and localization in aerospace sandwich structurescitations
- 2022Journal of Composite Materials / A framework for physics-driven generation of feature data for strain-based damage detection in aerospace sandwich structurescitations
- 2022Polymers and Polymer Composites / Correction factors for in-plane shear strength and stiffness testing of flat angle-ply composite laminates with high Poisson’s ratios
- 2022Additive Manufacturing / Shear property measurement of additively manufactured continuous fibre reinforced plastics by in-plane torsion testingcitations
- 2021Continuum Mechanics and Thermodynamics / Enhanced characterization of the yield behavior of sheet metal at torsional load using digital image correlation methodscitations
- 2021Journal of Composite Materials / Implications of free-edge effect at thin plain-woven carbon fiber reinforced plastic laminates with out-of-plane waviness under cyclic loadingcitations
- 2021Applied Sciences / Vibration-based thermal health monitoring for face layer debonding detection in aerospace sandwich structurescitations
- 2021Engineering Failure Analysis / Structural health monitoring of aerospace sandwich structures via strain measurements along zero-strain trajectoriescitations
- 2020Structural Health Monitoring / Improved current injection pattern for the detection of delaminations in carbon fiber reinforced polymer plates using electrical impedance tomographycitations
- 2020Materials Science & Engineering Technology / On the fatigue and fracture behavior of necked double shear lugs for aircraft applications : Zum Ermüdungs‐ und Bruchverhalten von verjüngten doppelschnittigen Augenverbindungen für Anwendungen im Flugzeugbaucitations
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article
Simultaneous laser ultrasonic measurement of sound velocities and thickness of plates using combined mode local acoustic spectroscopy
Abstract
Standard ultrasonic thickness measurements require the sound velocity of the sample to be known and vice versa. We present a method, which we have termed combined mode local acoustic spectroscopy (CoMLAS) for simultaneously determining a plate’s thickness and sound velocities without requiring such a priori knowledge. It is based on a combination of three guided wave modes sustained by a plate at discrete frequencies, which we generate and detect using laser ultrasound. We use a pulsed laser that is shaped into a periodic line pattern on the sample’s surface to generate elastic waves and measure the response at the pattern’s center with a vibrometer. The surface acoustic wave mode produces an interference peak in the response spectrum at the frequency corresponding to the wavelength matching the pattern line spacing. By limiting the total size of the excitation pattern, we can simultaneously generate two zero-group-velocity plate resonances, providing two additional peaks in the spectrum. The plate’s local thickness and longitudinal and transverse sound velocities are calculated from the peak frequencies. We demonstrate the feasibility of CoMLAS on steel and aluminum sheets with a thickness of around 2 mm by resolving thickness steps and temperature-induced changes in the sound velocities. Using numerical simulations and control experiments, we provide insights into the method’s accuracy and limitations. The choice of excitation pattern, the method’s sensitivity, and the influence of sample inhomogeneity and anisotropy are discussed. CoMLAS does not require scanning mechanics and provides local plate properties. The results shown are achieved with low-energy lasers and signal averaging. Considerations on signal-to-noise ratio indicate that a realization with available lasers of higher energy will enable single-shot measurements. This qualifies the method for use on moving samples in an industrial environment.