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Volume 8, Number 3, September 2023 , pages 219-236 DOI: https://doi.org/10.12989/acd.2023.8.3.219 |
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Finite element modeling of laser ultrasonics nondestructive evaluation technique in ablation regime |
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Salman Shamsaei and Farhang Honarvar
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| Abstract | ||
| In this paper, finite element modeling of the laser ultrasonics (LU) process in ablation regime is of interest. The momentum resulting from the removal of material from the specimen surface by the laser beam radiation in ablation regime is modeled as a pressure pulse. To model this pressure pulse, two equations are required: one for the spatial distribution and one for the temporal distribution of the pulse. Previous researchers have proposed various equations for the spatial and temporal distributions of the pressure pulse in different laser applications. All available equations are examined and the best combination of the temporal and spatial distributions of the pressure pulse that provides the most accurate results is identified. This combination of temporal and spatial distributions has never been used for modeling laser ultrasonics before. Then by using this new model, the effects of variations in pulse duration and laser spot radius on the shape, amplitude, and frequency spectrum of ultrasonic waves are studied. Furthermore, the LU in thermoelastic regime is simulated by this model and compared with LU in ablation regime. The interaction of ultrasonic waves with a defect is also investigated in the LU process in ablation regime. Good agreement of the results obtained from the new finite element model and available experimental data confirms the accuracy of the proposed model. | ||
| Key Words | ||
| ablation regime; finite element modeling; laser ultrasonics; nondestructive evaluation; pressure pulse | ||
| Address | ||
| Salman Shamsaei and Farhang Honarvar: NDE Lab, Faculty of Mechanical Engineering, K. N. Toosi University of Technology, 7 Pardis St., Mollasadra Ave., Vanak Sq., Tehran, Iran | ||
