Design of Composite Materials for Improved Loss-of-Lubrication Survivability of Hybrid Rotorcraft Gears

Hybrid gears featuring steel teeth mated to a composite body provide the potential for significant weight savings in aerospace applications such as rotorcraft and geared turbofan engines. For hybrid gears to be viable for use in these applications, they must not degrade mechanical performance or thermal characteristics, particularly under loss-of-lubrication operation. The heat generated by loss-of-lubrication operation may be especially problematic for the fiber-reinforced polymer composite materials used in hybrid steel-composite gear prototypes. Initial hybrid gear design and testing is described in the literature, but no prior studies have investigated optimization of the composite material for thermal performance. In the study presented herein, conductive fibers and high-temperature polymers are introduced to make a composite material better suited to high-temperature and loss-of-lubrication. Channel-flow resin transfer molding was used to fabricate composites with a variety of configurations, including hybrid reinforcement alternating highly-conductive pitch-based carbon fiber plies with typical high-strength PAN-based carbon fiber plies. Performance was evaluated by thermal conductivity measurement and compression strength testing. Finite element modeling was performed to quantify strength and stiffness requirements for the composite gear web and to investigate the effects of using plies of different stiffness in a hybrid laminate. Results of this study show that the in-plane thermal conductivity of composite laminates can be greatly increased by using hybrid reinforcement, but the hybrid gear web design must account for the low compression strength of the hybrid reinforcement to ensure that the structural integrity of the composite gear web is not compromised.

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Work Title Design of Composite Materials for Improved Loss-of-Lubrication Survivability of Hybrid Rotorcraft Gears
Access
Open Access
Creators
  1. Matthew Waller
  2. Kevin L Koudela
  3. Sean Michael Mcintyre
Keyword
  1. hybrid gear
  2. composite materials
  3. steel-composite hybrid gear
License In Copyright (Rights Reserved)
Work Type Conference Proceeding
Acknowledgments
  1. The authors would like to acknowledge Dr. Thomas Juska (Penn State) for his assistance with channel-flow resin transfer molding (RTM). The authors would also like to thank Dr. Gary Roberts and Dr. Sandi Miller (NASA Glenn Research Center) for supplying bismaleimide (BMI) prepreg material, and the American Gear Manufacturers Association (AGMA) for their generous scholarship support.
Publisher
  1. The Vertical Flight Society
Publication Date May 13, 2019
Subject
  1. hybrid gears
  2. composite materials
Language
  1. English
Deposited May 11, 2021

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Version 1
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  • Created
  • Updated Acknowledgments Show Changes
    Acknowledgments
    • The authors would like to acknowledge Dr. Thomas Juska (Penn State) for his assistance with channel-flow resin transfer molding (RTM). The authors would also like to thank Dr. Gary Roberts and Dr. Sandi Miller (NASA Glenn Research Center) for supplying bismaleimide (BMI) prepreg material, and the American Gear Manufacturers Association (AGMA) for their generous scholarship support.
  • Added Creator Matthew Waller
  • Added Creator Kevin L Koudela
  • Added Creator Sean Michael Mcintyre
  • Added waller2019design.pdf
  • Updated Subject, Language, License Show Changes
    Subject
    • hybrid gears, composite materials
    Language
    • English
    License
    • https://rightsstatements.org/page/InC/1.0/
  • Published
  • Updated
  • Updated