Journal of Failure Analysis and Prevention

, Volume 12, Issue 6, pp 670–682 | Cite as

Evaluation of the Effects of Corrosion on Fatigue Life of Clad Aluminum Alloy 2024-T3-Riveted Lap Joints with Acoustic Emission Monitoring

Technical Article---Peer-Reviewed
  • 299 Downloads

Abstract

Corrosion affects the fatigue life of clad aluminum alloy-riveted lap joints, such as those found on an aircraft fuselage structure. Single-, double-, and triple-column-riveted lap joint specimens were fabricated and corroded in a Q-Fog accelerated corrosion chamber for five months using an ASTM G85-A5 prohesion test. Specimens were taken out of the chamber every 4 weeks, and the corrosion products which had been deposited on them were removed by immersion in concentrated nitric acid. For each corroded specimen, the mass loss with corresponding corrosion rate was determined. The specimens were fatigue loaded to failure on an MTS Universal Testing Machine with acoustic emission monitoring. Results indicate that exposure of lap joint specimens to this corrosive environment increased corrosion (mass loss), corrosion rate, and significantly reduced fatigue life. For a prolonged exposure in the corrosive environment, the fatigue life was reduced to zero, which has significant implication for aging aircraft. Acoustic emission monitoring successfully detected fatigue failure. Two failure modes, multisite crack damage and shear of the rivets, were observed.

Keywords

Corrosion Fatigue life Accelerated corrosion testing Riveted lap joints Acoustic emission 

Notes

Acknowledgments

This research was partially supported by the Air Force Research Laboratory through contract to Missouri University of Science and Technology Center for Aerospace Manufacturing Technology, Contract No. FA8650-04-704. The Graduate Research Assistantship funds from this grant, and the Intelligent Systems Center, as well as the Graduate Teaching Assistantship provided by the Department of Mechanical and Aerospace Engineering at Missouri University of Science and Technology, are gratefully acknowledged. The authors would like to thank Dr. K. Chandrashekhara and Dr. M. Bohner for serving as committee members and examining this study. The authors would also like to thank Dr. C. Ramsey for his assistance in the failure analysis of failed specimens; Dr. F. Blum for granting access to his lab to conduct corrosion removal tests; Dr. M. Van de Mark for lending his ultrasonic bath; and Mr. J. Bradshaw for his assistance in using the MTS 880 Universal Testing Machine for conducting fatigue tests.

References

  1. 1.
    Jones, R., Molent, L., Pitt, S.: Study of multi-site damage of fuselage lap joints. Theor. Appl. Fract. Mech. 32(2), 81–100 (1999)CrossRefGoogle Scholar
  2. 2.
    Miller, D.: Corrosion control on aging aircraft: what is being done? Mater. Perform. 30, 10–11 (1990)Google Scholar
  3. 3.
    Australian Government. Australian Transport Safety Bureau: ATSB Transport Safety Report. Aviation Research and Analysis Report—B20050205, Final; How Old is Too Old? The impact of ageing aircraft on aviation safety, Feb 2007Google Scholar
  4. 4.
    www.corrosion-doctors.org. Last visited 9 Sept 2005
  5. 5.
    Bellenger, F., Mazille, H., Idrissi, H.: Use of acoustic emission technique for the early detection of aluminum alloys exfoliation corrosion. NDT E Int. 35(6), 385–392 (2002)CrossRefGoogle Scholar
  6. 6.
    Pierce, J., Hoppe, W., Petricola, D.: A corrosion growth experiment using model lap joints. In: Proceedings of the Fourth Joint DoD/FAA/NASA Conference on Aging Aircraft, St. Louis, May 2000Google Scholar
  7. 7.
    Wei, R.P., Harlow, D.G.: Corrosion and corrosion fatigue of aluminum alloys—an aging aircraft issue. In: Proceedings of the 7th International Fatigue Congress, vol. 4, pp. 2197–2204, Beijing, 1999Google Scholar
  8. 8.
    Bellinger, N.C., Forsyth, D.S., Komorowski, J.P.: Damage Characterization of Corroded 2024-T3 Fuselage Lap Joints. National Research Council Canada, Institute of Aerospace Research, Ottawa, 2001Google Scholar
  9. 9.
    Gruenberg, K.M., Craig, B.A., Hillberry, B.M., Bucci, R.G., Hinkle, A.J.: Predicting fatigue life of pre-corroded 2024-T3 aluminum from breaking load tests. Int. J. Fatigue 26(6), 615–627 (2004)CrossRefGoogle Scholar
  10. 10.
    Liao, M., Bellinger, N.C., Komorowski, J.P.: Analytical Methodologies for Fatigue Life Prediction of Corroded Fuselage Splices. www.agingaircraft2001.com. Last visited 17 June 2005
  11. 11.
    Furuta, S., Terada, H., Sashikuma, H., Fatigue strength of fuselage joint structures under ambient and corrosive environment. In: Fatigue in New and Aging Aircraft: ICAF Symposium 1997, pp. 231–249, West Midlands, 1997Google Scholar
  12. 12.
    Connor, Z., Fine, M., Moran, B.: A study of fatigue crack generation and growth in riveted Alclad 2024T3 specimens. In: Proceedings of the FAA-NASA Symposium on the Continued Airworthiness of Aircraft Structures, DOT/FAA/AR-97/2, II, Atlantic City, 1997Google Scholar
  13. 13.
    ASTM G1–03: Standard Practice for Preparing, Cleaning and Evaluating Corrosion Test Specimens. ASTM International, West Conshohocken, 2003Google Scholar
  14. 14.
    ASTM G85: Standard Practice for Modified Salt Spray (Fog) Testing. ASTM International, West Conshohocken, 2002Google Scholar
  15. 15.
    Q-Fog Operating Manual. Q-Panel Lab Products, Cleveland, March 2000Google Scholar
  16. 16.
    Okafor, A.C., Nnadili, C.D.: Investigation of the effects of corrosion and fatigue on the failure modes of clad aluminum alloy riveted lap joint specimens. J. Eng. Fail. Anal., submitted [MS Thesis by Christopher Nnadili, Missouri University of Science and Technology, Rolla, Missouri, pp. 41–88, 2005]Google Scholar
  17. 17.
    Ferrer, K.S., Kelly, R.G.: Comparison of Methods for Removal of Corrosion Product from AA2024-T3, pp. 110–117. NACE International, Houston (2001)Google Scholar
  18. 18.
    Sheridan, W.D.: Reference Data Sheet for Aluminum. http://www.meridianeng.com. Last visited 2 Aug 2005
  19. 19.
    Material Safety Data Sheet for Nitric Acid 20–70%. http://www.nanotech.wisc.edu. Last visited 9 Aug 2005
  20. 20.
    McIntire, P., Miller, R.K.: Nondestructive Testing Handbook, 2nd edn., vol. 5: Acoustic Emission Testing. American Society for Nondestructive Testing, Houston, 1987Google Scholar
  21. 21.
    Silva, L.F.M., Goncalves, J.P.M., Oliviera, F.M.F., de Castro, P.M.S.T.: Multiple-site damage in riveted lap-joints: experimental simulation and finite element prediction. Int. J. Fatigue 22, 319–338 (2000)CrossRefGoogle Scholar

Copyright information

© ASM International 2012

Authors and Affiliations

  1. 1.Nondestructive Evaluation and Structural Health Monitoring Laboratory, Department of Mechanical and Aerospace EngineeringMissouri University of Science and TechnologyRollaUSA

Personalised recommendations