Share Email Print

Proceedings Paper

A comparative study of fatigue damage sensing in aluminum alloys using electrical impedance and laser ultrasonic methods
Author(s): Lindsey Channels; Debejyo Chakraborty; Brad Butrym; Narayan Kovvali; James Spicer; Antonia Papandreou-Suppappola; Mana Afshari; Daniel Inman; Aditi Chattopadhyay
Format Member Price Non-Member Price
PDF $14.40 $18.00
cover GOOD NEWS! Your organization subscribes to the SPIE Digital Library. You may be able to download this paper for free. Check Access

Paper Abstract

Fatigue damage sensing and measurement in aluminum alloys is critical to estimating the residual useful lifetime of a range of aircraft structural components. In this work, we present electrical impedance and ultrasonic measurements in aluminum alloy 2024 that has been fatigued under high cycle conditions. While ultrasonic measurements can indicate fatigue-induced damage through changes in stiffness, the primary indicator is ultrasonic attenuation. We have used laser ultrasonic methods to investigate changes in ultrasonic attenuation since simultaneous measurement of longitudinal and shear properties provides opportunities to develop classification algorithms that can estimate the degree of damage. Electrical impedance measurements are sensitive to changes in the conductivity and permittivity of materials - both are affected by the microstructural damage processes related to fatigue. By employing spectral analysis of impedance over a range of frequencies, resonance peaks can be identified that directly reflect the damage state in the material. In order to compare the impedance and ultrasonic measurements for samples subjected to tension testing, we use processing and classification tools that are matched to the time-varying spectral nature of the measurements. Specifically, we process the measurements to extract time-frequency features and estimate stochastic variation properties to be used in robust classification algorithms. Results are presented for fatigue damage identification in aluminum lug joint specimens.

Paper Details

Date Published: 17 April 2009
PDF: 10 pages
Proc. SPIE 7295, Health Monitoring of Structural and Biological Systems 2009, 72950Q (17 April 2009); doi: 10.1117/12.815980
Show Author Affiliations
Lindsey Channels, The Johns Hopkins Univ. (United States)
Debejyo Chakraborty, Arizona State Univ. (United States)
Brad Butrym, Virginia Polytechnic Institute and State Univ. (United States)
Narayan Kovvali, Arizona State Univ. (United States)
James Spicer, The Johns Hopkins Univ. (United States)
Antonia Papandreou-Suppappola, Arizona State Univ. (United States)
Mana Afshari, Virginia Polytechnic Institute and State Univ. (United States)
Daniel Inman, Virginia Polytechnic Institute and State Univ. (United States)
Aditi Chattopadhyay, Arizona State Univ. (United States)

Published in SPIE Proceedings Vol. 7295:
Health Monitoring of Structural and Biological Systems 2009
Tribikram Kundu, Editor(s)

© SPIE. Terms of Use
Back to Top