Location

La Jolla, CA

Start Date

1-1-1993 12:00 AM

Description

One of the challenges in the acoustoelastic measurement of stress is the achievement of high spatial resolution. Since stress induced velocity shifts are generally small (~0.01%), the required precision of time and distance measurements can be quite high for the short propagation distances required. This paper presents a set of design criteria which can guide the experimentalist in choosing the most suitable measurement configuration for Rayleigh wave techniques. Three approaches for measuring the acoustic velocity are considered: measurement of arrival time versus transducer separation for several discrete positions, measurement of arrival time for a pair of transducers at a fixed separation, and inference of the velocity from the V(z) response of an acoustic microscope. For each case, analytical formulae are developed which relate the precision of velocity measurement to the experimental parameters and the expected uncertainty in the data. These formulae are confirmed by comparison to experiment.

Book Title

Review of Progress in Quantitative Nondestructive Evaluation

Volume

12B

Chapter

Chapter 7: Nonlinearity, Deformation and Fracture

Section

Stress and Fatigue Cracks

Pages

2121-2128

DOI

10.1007/978-1-4615-2848-7_270

Language

en

File Format

application/pdf

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Jan 1st, 12:00 AM

The Spatial Resolution of Rayleigh Wave, Acoustoelastic Measurement fo Stress

La Jolla, CA

One of the challenges in the acoustoelastic measurement of stress is the achievement of high spatial resolution. Since stress induced velocity shifts are generally small (~0.01%), the required precision of time and distance measurements can be quite high for the short propagation distances required. This paper presents a set of design criteria which can guide the experimentalist in choosing the most suitable measurement configuration for Rayleigh wave techniques. Three approaches for measuring the acoustic velocity are considered: measurement of arrival time versus transducer separation for several discrete positions, measurement of arrival time for a pair of transducers at a fixed separation, and inference of the velocity from the V(z) response of an acoustic microscope. For each case, analytical formulae are developed which relate the precision of velocity measurement to the experimental parameters and the expected uncertainty in the data. These formulae are confirmed by comparison to experiment.