Location

La Jolla, CA

Start Date

1-1-1993 12:00 AM

Description

A material may appear homogeneous and anisotropic when the scale of its fabric is smaller than the wavelengths that measure it. These structures can result from a variety of causes such as the thin layering in composites or stress resultant oriented microcracking. In the case of a stressed composite, the resultant anisotropy is a complex combination of the two component anisotropics. Hood and Schoenberg [1] showed theoretically that the effects of vertical fractures can be separated from a background that is already anisotropic. We propose an ultrasonic experiment designed to verify their theories. The vertical fracturing is scaled and simulated by the plate method of Hsu and Schoenberg [2] and superposed in a transversely isotropic (TI) material. The resultant material is presumed to have orthorhombic symmetry. Contact measurements are made to determine the elastic moduli. The results give the additional compliance that the fractures add to the system as well as the elastic properties of the original background material as if it had no vertical fractures.

Book Title

Review of Progress in Quantitative Nondestructive Evaluation

Volume

12B

Chapter

Chapter 5: Engineered Materials

Section

Composite Properties

Pages

1249-1256

DOI

10.1007/978-1-4615-2848-7_159

Language

en

File Format

application/pdf

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Jan 1st, 12:00 AM

Isolating Fracture-Induced Anisotropy from Background Anisotropy

La Jolla, CA

A material may appear homogeneous and anisotropic when the scale of its fabric is smaller than the wavelengths that measure it. These structures can result from a variety of causes such as the thin layering in composites or stress resultant oriented microcracking. In the case of a stressed composite, the resultant anisotropy is a complex combination of the two component anisotropics. Hood and Schoenberg [1] showed theoretically that the effects of vertical fractures can be separated from a background that is already anisotropic. We propose an ultrasonic experiment designed to verify their theories. The vertical fracturing is scaled and simulated by the plate method of Hsu and Schoenberg [2] and superposed in a transversely isotropic (TI) material. The resultant material is presumed to have orthorhombic symmetry. Contact measurements are made to determine the elastic moduli. The results give the additional compliance that the fractures add to the system as well as the elastic properties of the original background material as if it had no vertical fractures.