17 April 2009 A comparative study of fatigue damage sensing in aluminum alloys using electrical impedance and laser ultrasonic methods
Author Affiliations +
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.
© (2009) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Lindsey Channels, Lindsey Channels, Debejyo Chakraborty, Debejyo Chakraborty, Brad Butrym, Brad Butrym, Narayan Kovvali, Narayan Kovvali, James Spicer, James Spicer, Antonia Papandreou-Suppappola, Antonia Papandreou-Suppappola, Mana Afshari, Mana Afshari, Daniel Inman, Daniel Inman, Aditi Chattopadhyay, Aditi Chattopadhyay, } "A comparative study of fatigue damage sensing in aluminum alloys using electrical impedance and laser ultrasonic methods", Proc. SPIE 7295, Health Monitoring of Structural and Biological Systems 2009, 72950Q (17 April 2009); doi: 10.1117/12.815980; https://doi.org/10.1117/12.815980

Back to Top