Influence of Stress Relaxation in Hybrid Composite/Metal Bolted Connections

Abstract

An experimental investigation of the influence of stress relaxation on watertight integrity of hybrid composite-to-metal bolted connections is presented. This study focuses on the effects of bolt reloading, use of tapered-head bolts versus protruding-head bolts, and briefly addresses environmental effects. All tests were conducted for a time period of at least three months, in order to estimate primary and secondary stress relaxation effects. The reloading tests show that some of the preload in the connections can be maintained with periodic retightening of the bolts. In a limited amount of testing it was observed that temperature shifts caused more rapid stress relaxation rates. Little difference in relaxation was observed when comparing tapered-head bolts with protruding-head bolts, given that roughly equal stress relaxation rates were observed. Further research on this area is required.

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Document Details

Document Type
Technical Report
Publication Date
Jan 15, 2005
Accession Number
ADA429921

Entities

People

  • Keith A. Berube
  • Keith N. Pelletier
  • Vincent Caccese

Organizations

  • University of Maine

Tags

Communities of Interest

  • Energy and Power Technologies
  • Ground and Sea Platforms
  • Sensors

DTIC Thesaurus Topics

  • Biocomposites
  • Composite Material Fabrication
  • Composite Materials
  • Fiber Reinforced Polymers
  • Hulls (Marine)
  • Laminates
  • Materials Laboratories
  • Materials Processing
  • Materials Science
  • Materials Testing
  • Mechanics
  • Micromechanics
  • Modulus Of Elasticity
  • Plastics
  • Polymer Matrix Composites
  • Reinforced Plastics
  • Test Methods

Fields of Study

  • Engineering

Readers

  • Mechanical Engineering/Mechanics of Materials.
  • Structural Health Monitoring of Composite Structures.