Low Computation Acoustic Emissions Structural Health Monitoring Through Analog Signal Pre-Processing

##plugins.themes.bootstrap3.article.main##

##plugins.themes.bootstrap3.article.sidebar##

Published Oct 2, 2017
Rune Schlanbusch Eric Bechhoefer Thomas J. J. Meyer

Abstract

In this research an innovative acoustic emission sensing system has been developed intended for structural fatigue crack monitoring. The innovation lies in analog pre-processing of the detected acoustic emissions for signal enveloping, thus relying on cheap high bandwidth components. The technique is based on heterodyning the amplified acoustic emission signal with a carrier signal of a chosen frequency. Next, the signal is filtered and the signal envelope is obtained by phase shifting the signal by pi/2 creating an analytic signal that is digitally sampled. This results in need of low sampling rate digital acquisition equipment giving relatively small amounts of data to be processed and stored, considerably reducing the system cost. This is particularly suitable for applications involving large or complex structures to be monitored, where a multitude of sensors are needed. The system was built and tested on aluminum test coupons during tension-tension fatigue. The envelope signal is filtered for background noise through thresholding based on statistical knowledge of the noise distribution. The accumulation of acoustic activity shows promising results with an early period of high acoustic activity during settling of the material that asymptotically converges at a certain level. At the next stage, there is no activity until a certain point is reached where a sudden ramp up of AE is detected close to the end of the experiment. Through
extensometer measurement, the change in coupon length at this point in time strongly indicates that the ramp up of AE activity is due to crack initiation and propagation.

How to Cite

Schlanbusch, R., Bechhoefer, E., & Meyer, T. J. J. (2017). Low Computation Acoustic Emissions Structural Health Monitoring Through Analog Signal Pre-Processing. Annual Conference of the PHM Society, 9(1). https://doi.org/10.36001/phmconf.2017.v9i1.2308
Abstract 509 | PDF Downloads 156

##plugins.themes.bootstrap3.article.details##

Keywords

SHM, Acoustic Emissions

References
Bechhoefer, E., Qu, Y., Zhu, J., & He, D. (2013). Signal processing techniques to improve an acoustic emissions sensor. In Proceedings of the annual conference of prognostics and health management society.
Berkovits, A.,&Fang, D. (1995). Study of fatigue crack characteristics by acoustic emission. Engineering Fracture Mechanics, 51(3), 401 - 416.
Drummond, G., Watson, J. F., & Acarnley, P. P. (2007). Acoustic emission from wire ropes during proof load and fatigue testing. NDT&E International, 40, 94-101.
Grosse, C. U., & Ohtsu, M. (Eds.). (2008). Acoustic emission testing. Springer.
ISO. (2003). Metallic materials – fatigue testing – axialstrain-controlled method (No. 12106:2003).
Lindley, T. C., Palmer, I. G., & Richards, C. E. (1978). Acoustic emission monitoring of fatigue crack growth. Materials Science and Engineering, 32(1), 1 - 15.
Liptai, R. G., Dunegan, H. L., & Tatro, C. A. (1969). Acoustic emissions generated during phase transformation in metals and alloys. International Journal of Nondestructive Testing, 1, 213-221.
Mizutani, Y. (Ed.). (2016). Practical acoustic emission testing. The Japanese Society for Non-Destructive Inspection, Springer.
Moskvina, V., & Zhigljavsky, A. (2003). An algorithm based on singular spectrum analysis for change-point detection. Communications in statistics. Simulation and computation, 32(2), 319-352.
Paris, P. C., Gomez, M. P., & Anderson, W. E. (1961). A rational analyic theory of fatigue. The Trend in Engineering, 13(1), 9-14.
Roberts, T. M., & Talebzadeh, M. (2003). Acoustic emission monitoring of fatigue crack propagation. Journal of Constructional Steel Research, 59(6), 695 - 712.
Van Hecke, B. E. (2015). Development of novel acoustic emission based methodology and tools for bearing fault diagnostics (Unpublished doctoral dissertation). University of Illinois at Chicago.
Yahr, G. T. (1993). Fatigue design curves for 6061-T6 aluminum (Tech. Rep.). Oak Ridge National Laboratory.
Section
Technical Research Papers

Most read articles by the same author(s)

<< < 1 2 3