Share Email Print
cover

Proceedings Paper

Active sensing of fatigue damage using embedded ultrasonics
Author(s): Walter A. Kruse; Andrei Zagrai; Vlasi Gigineishvili
Format Member Price Non-Member Price
PDF $14.40 $18.00

Paper Abstract

Dynamic measurements are widely used for structural condition assessment and damage detection. A wide range of studies are available on vibration-based detection and identification of fatigue cracks in simple and complex structures. This research explores the application of the electromechanical impedance method and nonlinear resonance measurements to high frequency detection of incipient fatigue damage in aluminum alloy specimens. The electromechanical impedance method relies on the coupling between the mechanical properties of a structure and the electrical properties of attached piezoelectric wafer active sensors (PWAS). This coupling allows structural properties to be inferred from the electrical impedance signature of the sensor. In this study, the electromechanical impedance method is utilized for assessment of material deterioration under cyclic fatigue loads. Aluminum specimens were subjected to increasing fatigue cycles at stress amplitudes below the yield point, and electromechanical impedance signatures were taken at discrete levels of fatigue damage. Linear and nonlinear features of the impedance signatures were compared for different damage conditions. The results show a downward frequency shift of impedance peaks with increasing fatigue load. This frequency shift is observed before visible crack development and fracture. Nonlinear resonance tests were applied to fatigued aluminum samples. PWAS were utilized for transmission and reception of elastic waves at increasing amplitude levels. Variations in structural dynamic characteristics were considered for different excitation conditions and increasing damage severity. This paper discusses damage detection capabilities of each method and provides perspectives for utilizing information on incipient damage for predicting structural performance under known operational loads.

Paper Details

Date Published: 9 April 2010
PDF: 12 pages
Proc. SPIE 7650, Health Monitoring of Structural and Biological Systems 2010, 76501J (9 April 2010); doi: 10.1117/12.847672
Show Author Affiliations
Walter A. Kruse, New Mexico Institute of Mining and Technology (United States)
Andrei Zagrai, New Mexico Institute of Mining and Technology (United States)
Vlasi Gigineishvili, New Mexico Institute of Mining and Technology (United States)


Published in SPIE Proceedings Vol. 7650:
Health Monitoring of Structural and Biological Systems 2010
Tribikram Kundu, Editor(s)

© SPIE. Terms of Use
Back to Top