Thermoelastic generation of ultrasound by line-focused laser irradiation

Author (s): Arias, I., Achenbach, J. D.
Journal: International Journal of Solids and Structures

Volume: 40, Issue 25
Pages: 6917 – 6935
Date: 2003

A two-dimensional theoretical model for the field generated in the thermoelastic regime by line-focused laser illumination of a homogeneous, isotropic, linearly elastic half-space is presented. The model accounts for the efiects of thermal difiu- sion and optical penetration, as well as the finite width and duration of the laser source. The model is obtained by solving the thermoelastic problem in plane strain, rather than by integrating available solutions for the point-source, leading to a lower computational efiort. The well-known dipole model follows from appropriate lim- its. However, it is shown that, by simple elasticity arguments, the strength of the dipole can be related a-priori to the heat input and certain material properties. The strength is found to be smaller than that of the dipoles equivalent to a buried source due to the efiect of the free surface. This fact has been overlooked by some previous researchers. Excellent quantitative agreement with experimental observa- tions provides validation for the model. Some representative results are presented to illustrate the generated field and provide insight into the relevance of the difierent mechanisms taken into account in the model.



title = "Thermoelastic generation of ultrasound by line-focused laser irradiation ",
journal = "International Journal of Solids and Structures ",
volume = "40",
number = "25",
pages = "6917 - 6935",
year = "2003",
note = "Special issue in Honor of George J. Dvorak ",
issn = "0020-7683",
doi = "http://dx.doi.org/10.1016/S0020-7683(03)00345-7",
url = "http://www.sciencedirect.com/science/article/pii/S0020768303003457",
author = "Irene Arias and Jan D. Achenbach",
keywords = "Laser-generation",
keywords = "Thermoelastic regime",
keywords = "Line-source",
keywords = "Modelling",
keywords = "Non-destructive testing "