Application of a two-layer semi-analytical model for the improvement of laser-ultrasonic generation

Lafond, Emmanuel; Coulette, R.; Grand, Christine; Nadal, Marie-Hélène; Dupont, Bruno; Lepoutre, F.; Balageas, D.; Pétillon, Odile

doi:10.1016/s0963-8695(97)00030-3

Cited by 8 publications

(2 citation statements)

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“…Only, the modeling of the displacement field which allows a two-dimensional ͑2D͒ description of the acoustic field and has been validated by the experiment for a lot of configurations. 34 In the present work, the thermoelastic model takes into account the following assumptions:…”

Section: Thermoelastic Modelingmentioning

confidence: 99%

“…The interferometric response can be modeled following, for example, the elastic model developed in the case of laser ultrasonic probing of a paint layer on an aluminum substrate. 34 In some experiments, the specific time profile of the epicentral displacement generated by laser irradiation of a constraining layer consisting of a transparent material placed over the irradiated face of the target, 35 or a polymer coating, 22 has been clearly exhibited, but the relation between the propagation of the waves and the normal displacement at the epicenter has not been determined except for transparent layers having the same elastic and thermal properties as the metallic substrate. 36,37 The aim of the present study is to propose an alternative method using laser ultrasonics devoted to assess the practical adhesion of transparent coatings.…”

Section: Introductionmentioning

confidence: 99%

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Evaluation of the coating–substrate adhesion by laser-ultrasonics: Modeling and experiments

Rosa

Oltra

Nadal

2002

Journal of Applied Physics

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The aim of the present study is to investigate a laser-ultrasonic method to determine the oxide-coating's adhesion strength on a metallic substrate. In order to demonstrate this method a completely contactless system is used, combining laser generation and detection of ultrasonic waves. A nanosecond pulsed Nd:YAG laser is used to irradiate the transparent oxide coatings, while the normal displacement of the rear surface of the metallic substrate is detected at the epicenter by a laser heterodyne interferometer. Increasing the laser beam energy, the generated acoustic wave forms are correlated with the thermoelastic regime, the fracture of the coating-substrate interface, and finally the expulsion of the coating. The generation of ultrasonic signals in the thermoelastic regime is described by a two-dimensional model suitable to calculate the in-and out-of-plane components of the mechanical displacement versus time. The values of the so-called practical adhesion found are in agreement with those obtained by classic contact techniques ͑tensile adhesion test, indentation, bending test͒. This work demonstrates the suitability of this quantitative and contactless test to evaluate the coating-substrate adhesion.

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Section: Thermoelastic Modelingmentioning

confidence: 99%