Location

La Jolla, CA

Start Date

1980 12:00 AM

Description

The theory of acoustoelasticity predicts that a plane longitudinal acoustic wave passing through a solid which is already in a deformed state will propagate with a velocity (v) which is different from the (v0) of the same wave propagating through the undeformed medium. It may be shown that Δv/v0 = (v-v0)/v0 = B(σ12) where σ1 and σ2 are the principal stress in the plane normal to the wave propagation direction and B is the acoustoelastic constant. Wave transit time measurements allow the relative velocity change Δv/v0 to be determined, so that contours of constant principal stress sum (σ12) may be mapped by acoustically scanning a stressed solid. We have used the technique described above to characterize the states of stress in cracked and notched aluminum panels. A method for extracting crack stress intensity factors from the acoustic data is proposed and illustrated for center-cracked panel specimens. The results indicate that the technique may offer a promising method for nondestructive testing and evaluation.

Book Title

Proceedings of the ARPA/AFML Review of Progress in Quantitative NDE

Chapter

11. Ultrasonics, Material Properties

Pages

422-428

Language

en

File Format

application/pdf

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Jan 1st, 12:00 AM

The Use of Acoustoelastic Measurements to Characterize the Stress States in Cracked Solids

La Jolla, CA

The theory of acoustoelasticity predicts that a plane longitudinal acoustic wave passing through a solid which is already in a deformed state will propagate with a velocity (v) which is different from the (v0) of the same wave propagating through the undeformed medium. It may be shown that Δv/v0 = (v-v0)/v0 = B(σ12) where σ1 and σ2 are the principal stress in the plane normal to the wave propagation direction and B is the acoustoelastic constant. Wave transit time measurements allow the relative velocity change Δv/v0 to be determined, so that contours of constant principal stress sum (σ12) may be mapped by acoustically scanning a stressed solid. We have used the technique described above to characterize the states of stress in cracked and notched aluminum panels. A method for extracting crack stress intensity factors from the acoustic data is proposed and illustrated for center-cracked panel specimens. The results indicate that the technique may offer a promising method for nondestructive testing and evaluation.