Campus Units

Aerospace Engineering, Center for Nondestructive Evaluation (CNDE)

Document Type

Article

Publication Version

Published Version

Publication Date

2015

Journal or Book Title

The Journal of the Acoustical Society of America

Volume

137

Issue

2

First Page

617

Last Page

624

DOI

10.1121/1.4906165

Abstract

This paper presents the study of non-classical nonlinear response of fiber-reinforced composites. Nonlinear elastic wave methods such as nonlinearresonant ultrasound spectroscopy (NRUS) and nonlinear wave modulation spectroscopy have been used earlier to detect damages in several materials. It was observed that applying these techniques to composites materials becomes difficult due to the significant inherent baseline nonlinearity. Understanding the non-classical nonlinear nature of the composites plays a vital role in implementing nonlinear acoustic techniques for material characterization as well as qualitative nondestructive testing of composites. Since fiber reinforced composites are orthotropic in nature, the baseline response variation with fiber orientation is very important. This work explores the nature of the inherent nonlinearity by performing nonlinear resonant spectroscopy (NRS) in intact unidirectional carbon/epoxy samples with different fiber orientations with respect to major axis of the sample. Factors such as frequency shifts, modal damping ratio, and higher harmonics were analyzed to explore the non-classical nonlinear nature of these materials. Conclusions were drawn based on the experimental observations.

Comments

This article is published as Chakrapani, Sunil Kishore, Daniel J. Barnard, and Vinay Dayal. "Influence of fiber orientation on the inherent acoustic nonlinearity in carbon fiber reinforced composites." The Journal of the Acoustical Society of America 137, no. 2 (2015): 617-624. DOI: 10.1121/1.4906165. Posted with permission.

Copyright Owner

Acoustical Society of America

Language

en

File Format

application/pdf

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