Location

La Jolla, CA

Start Date

1-1-1993 12:00 AM

Description

This paper presents a new technique to characterize the damage of a bonded component. The theoretical analysis models a damaged bond as a random distribution of small interphase cracks and cavities. Interaction of ultrasonic waves with these interfacial cracks are studied by a differential self-consistent scheme (DSS) in conjunction with the backscattering signal strength formula [1]. Here the multiple scattering problem from a distribution of interphase cracks is reduced to finding the crack opening displacement of a single interphase crack. Transmission coefficients are obtained explicitly in terms of the characteristic length, density of the interfacial defects and incident wave frequency, from the solution of a first order, ordinary differential equation. Experimental verification of the theoretical solution is performed on aluminum blocks joined by an epoxy layer with varying densities of interfacial cracks. Transmission coefficients from the epoxy layer are measured with a heterodyne interferometer. The measured transmission signals are compared to predicted values and information such as defect distribution and size is extracted.

Book Title

Review of Progress in Quantitative Nondestructive Evaluation

Volume

12B

Chapter

Chapter 5: Engineered Materials

Section

Bonded Joints

Pages

1587-1594

DOI

10.1007/978-1-4615-2848-7_202

Language

en

File Format

application/pdf

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Jan 1st, 12:00 AM

Nondestructive Characterization of Damaged Bonds

La Jolla, CA

This paper presents a new technique to characterize the damage of a bonded component. The theoretical analysis models a damaged bond as a random distribution of small interphase cracks and cavities. Interaction of ultrasonic waves with these interfacial cracks are studied by a differential self-consistent scheme (DSS) in conjunction with the backscattering signal strength formula [1]. Here the multiple scattering problem from a distribution of interphase cracks is reduced to finding the crack opening displacement of a single interphase crack. Transmission coefficients are obtained explicitly in terms of the characteristic length, density of the interfacial defects and incident wave frequency, from the solution of a first order, ordinary differential equation. Experimental verification of the theoretical solution is performed on aluminum blocks joined by an epoxy layer with varying densities of interfacial cracks. Transmission coefficients from the epoxy layer are measured with a heterodyne interferometer. The measured transmission signals are compared to predicted values and information such as defect distribution and size is extracted.