Fatigue Life Improvement Using In-situ Robotic Processes

  • Zahi Hajjar
  • Benoit Leblanc
Conference paper


Several repairs were developed by L-3 MAS on the CF-18 aircraft (Canadian Forces F/A-18) to remove fatigue damage at localized regions. These repairs generally consist in polishing or blending the component surface to remove cumulated fatigue damage and improve surface finish. Additionally, in some cases, shot-peening is used after surface renewal to improve the fatigue life.

Currently, no clear data or methodology exists to allow accounting for the benefit of surface renewal in analytical fatigue life predictions. Additionally, due to variability of the improvement provided by peening, no generic life improvement factors exist for shot-peening. Certification of surface renewal and peening modifications is usually completed using coupon fatigue testing specific to the location studied.

This paper summarizes some of the work completed in order to provide tools and data to account for surface renewal without requiring specific coupon programs.

Robotic surface improvement technologies developed and summarized in this paper have allowed obtaining more consistent and more predictable surface improvements. Finally, a coupon program has shown the benefit of surface renewal after several levels of fatigue exposure.


Fatigue Life Surface Finish Fatigue Damage None None Safe Life 
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  1. 1.
    Molent, L., Barter, S., Main, B.: Life assessment and repair of fatigue damaged high strength aluminium alloy structure using a peening rework method. Eng. Fail Anal. 15(1-2), 62–82 (2008)CrossRefGoogle Scholar
  2. 2.
    Sharp, P.K., Liu, Q., Barter, S.A., Baburamani, P., Clark, G.: Fatigue Life Recovery in Aluminium alloy aircraft structure. Fatigue Fract Engng. Mater Struct. 25, 99–110 (2002)CrossRefGoogle Scholar
  3. 3.
    Kioua, H., Forgues, S.: In-Situ Robotic Shot Peening for the Fatigue Life Improvement of Aircraft Structures. In: Proceedings of the 2003 Aerospace Technology and Innovation Conference, Canadian Aerospace and Space Institute, CASI (2003)Google Scholar
  4. 4.
    Takemoto, T., Jing, K.L., Tsakalakos, T., Weissmann, S., Kramer, I.R.: The importance of Surface Layer on fatigue Behavior of a Ti-6Al-4V Alloy. Metallurgical and Materials transactions A 14(1), 127–132 (1983)CrossRefGoogle Scholar
  5. 5.
    Jeelani, S., Scott, M.A.: How surface damage removal affects fatigue Life. Int. J. Fatigue 10(4), 257–260 (1988)CrossRefGoogle Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 2011

Authors and Affiliations

  • Zahi Hajjar
    • 1
  • Benoit Leblanc
    • 1
  1. 1.L-3 CommunicationsMilitary Aviation Services (MAS)MirabelCanada

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