Failure Analysis of Modular Lift Link, Lug Mounting, Self-Locking Nuts

Abstract

The U.S. Army Research Laboratory-Materials Directorate (USARL-MD) conducted a failure analysis of two self-locking nuts from an army attack helicopter, at the request of the U.S. Army Aviation and Troop Command (ATCOM). Light optical and scanning electron microscopy were utilized to characterize the fracture halves of the broken nuts. The self-locking nuts are governed by Specification MS21042, Nut, Self- Locking, 450 deg F, Reduced Hexagon, Reduced Height, Ring Base, Non-Corrosion Resistant Steel. During phase maintenance on the lift beam in the pylon area, maintenance crews noticed the bolts securing the lift link support lug were not properly seated. Further inspection showed that the left side self-locking nuts were cracked and/or missing. The right side nuts were also cracked.

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Document Details

Document Type
Technical Report
Publication Date
Apr 01, 1996
Accession Number
ADP010187

Entities

People

  • Scott M. Grendahl

Organizations

  • United States Army Research Laboratory

Tags

Communities of Interest

  • Advanced Electronics
  • Energy and Power Technologies

DTIC Thesaurus Topics

  • Attack Helicopters
  • Chemical Analysis
  • Corrosion
  • Corrosion Resistant Steels
  • Electron Microscopy
  • Failure Analysis
  • Failure Mode And Effect Analysis
  • Ferrium
  • Hardness
  • Hydrogen Embrittlement
  • Materials
  • Mechanical Properties
  • Microscopy
  • Military Research
  • Scanning Electron Microscopy
  • Stress Corrosion
  • Stress Corrosion Cracking

Readers

  • Electrical Engineering
  • Facility/Structural Engineering.
  • Materials Science and Engineering.

Technology Areas

  • Microelectronics
  • Microelectronics - Microelectromechanical Systems