Location

Brunswick, ME

Start Date

1-1-1997 12:00 AM

Description

Laser generation and detection of ultrasound has the obvious advantage of requiring no mechanical contact with the materials under investigation. Detection systems based on confocal Fabry-Perot interferometers can be used on surfaces that are rough, moving, and at elevated temperatures. This work describes the use of a laser-ultrasonic system for investigation of surface acoustic waves (SAWs) in composite laminates. SAWs in thick samples, also called Rayleigh waves, have displacement components both parallel and perpendicular to the surface. These components decay exponentially with distance from the surface, thus the wave motion is confined to a layer with thickness equal to about one wavelength. Because the wave propagation is mainly dependent upon material properties (including defects) near the surface, SAWs are an excellent tool for testing materials near the surface. Lamb waves are the counterparts of Rayleigh waves in thin samples with two free surfaces. A detailed discussion of Rayleigh and Lamb waves can be found in the treatise by Viktorov [1].

Book Title

Review of Progress in Quantitative Nondestructive Evaluation

Volume

16B

Chapter

Chapter 5: Engineered Materials

Section

Composites

Pages

1123-1126

DOI

10.1007/978-1-4615-5947-4_146

Language

en

File Format

application/pdf

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Jan 1st, 12:00 AM

Laser Generation and Detection of Lamb Waves in Graphite/Polymer Composite Laminates

Brunswick, ME

Laser generation and detection of ultrasound has the obvious advantage of requiring no mechanical contact with the materials under investigation. Detection systems based on confocal Fabry-Perot interferometers can be used on surfaces that are rough, moving, and at elevated temperatures. This work describes the use of a laser-ultrasonic system for investigation of surface acoustic waves (SAWs) in composite laminates. SAWs in thick samples, also called Rayleigh waves, have displacement components both parallel and perpendicular to the surface. These components decay exponentially with distance from the surface, thus the wave motion is confined to a layer with thickness equal to about one wavelength. Because the wave propagation is mainly dependent upon material properties (including defects) near the surface, SAWs are an excellent tool for testing materials near the surface. Lamb waves are the counterparts of Rayleigh waves in thin samples with two free surfaces. A detailed discussion of Rayleigh and Lamb waves can be found in the treatise by Viktorov [1].