Location

Brunswick, ME

Start Date

1-1-1997 12:00 AM

Description

In the previous year, results were presented in which the viscosity of calibration liquids were determined by measuring the reflection coefficient of laser generated shear waves. [1] The shear waves were launched with a pulsed Nd: YAG laser into an aluminum wedge and detected using a piezoelectric transducer. This year results are presented from a totally noncontact system, generating the shear waves with a pulsed laser and detecting the reflected shear waves with a laser interferometer. The design of the wedge was modified so that the shear waves are incident to the solid-liquid interface at nearly normal incidence. They reflect off this interface and are incident on the surface of detection at greater than the critical angle. This allows for the largest possible out-of-plane displacement, which can then be detected with the interferometer. This type of arrangement has been used with both aluminum and graphite wedges.

Book Title

Review of Progress in Quantitative Nondestructive Evaluation

Volume

16A

Chapter

Chapter 2: Emerging Inspection Technologies

Section

Laser Based Ultrasonics

Pages

539-545

DOI

10.1007/978-1-4615-5947-4_71

Language

en

File Format

application/pdf

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Jan 1st, 12:00 AM

Viscosity Measurement with Laser Ultrasonics

Brunswick, ME

In the previous year, results were presented in which the viscosity of calibration liquids were determined by measuring the reflection coefficient of laser generated shear waves. [1] The shear waves were launched with a pulsed Nd: YAG laser into an aluminum wedge and detected using a piezoelectric transducer. This year results are presented from a totally noncontact system, generating the shear waves with a pulsed laser and detecting the reflected shear waves with a laser interferometer. The design of the wedge was modified so that the shear waves are incident to the solid-liquid interface at nearly normal incidence. They reflect off this interface and are incident on the surface of detection at greater than the critical angle. This allows for the largest possible out-of-plane displacement, which can then be detected with the interferometer. This type of arrangement has been used with both aluminum and graphite wedges.