Location

Brunswick, ME

Start Date

1-1-1997 12:00 AM

Description

Laser generated ultrasound has been used to determine material properties and to characterize material defects [1–3]. To a large extent, the success of laser ultrasonics has been the researcher’s ability to correctly predict the temporal evolution of the displacement waveform resulting from pulsed laser irradiation. Theories that assume isotropic elastic properties work well for crystalline materials that have grain sizes that are small compared to the wavelength of the interrogating ultrasonic wave [4–5]. For single crystal samples or carbon epoxies, the elastic anisotropic nature must be taken into account. Royer and Dieulesaint [6] have shown, using a plane wave analysis, that the behavior of single crystal materials in the presence of an ultrasonic disturbance differ markedly from their isotropic counterparts. In particular for cubic and tetragonal systems, Royer and Dieulesaint [6] demonstrated that the decay rate of the Rayleigh wave disturbance varies strongly as a function of the anisotropy factor.

Book Title

Review of Progress in Quantitative Nondestructive Evaluation

Volume

16A

Chapter

Chapter 2: Emerging Inspection Technologies

Section

Laser Based Ultrasonics

Pages

475-481

DOI

10.1007/978-1-4615-5947-4_63

Language

en

File Format

application/pdf

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Jan 1st, 12:00 AM

Investigation of the Anisotropic Nature of Laser Generated Ultrasound in HCP Crystals and Unidirectional Carbon Epoxy Composites

Brunswick, ME

Laser generated ultrasound has been used to determine material properties and to characterize material defects [1–3]. To a large extent, the success of laser ultrasonics has been the researcher’s ability to correctly predict the temporal evolution of the displacement waveform resulting from pulsed laser irradiation. Theories that assume isotropic elastic properties work well for crystalline materials that have grain sizes that are small compared to the wavelength of the interrogating ultrasonic wave [4–5]. For single crystal samples or carbon epoxies, the elastic anisotropic nature must be taken into account. Royer and Dieulesaint [6] have shown, using a plane wave analysis, that the behavior of single crystal materials in the presence of an ultrasonic disturbance differ markedly from their isotropic counterparts. In particular for cubic and tetragonal systems, Royer and Dieulesaint [6] demonstrated that the decay rate of the Rayleigh wave disturbance varies strongly as a function of the anisotropy factor.