Development of Fracture Mechanics Concepts Applicable to Aircraft Structures.

Abstract

In Part A of this report, the feasibility of using an accelerated fatigue test program to predict constant amplitude fatigue lives of precracked specimens was examined. An analytical basis for the fracture mechanics approach was developed. The predicted curves from the accelerated test data were found to provide a good fit for the constant amplitude results in 2024-T3 and 7075-T6 aluminum alloys. These results indicate that the accelerated test data can be effectively employed to predict constant amplitude fatigue lives, while also providing a considerable reduction in testing time. Part B of this relates to effects of thickness and microstructure on nonlinear toughness parameters on CORONA-5. The variation of several linear and nonlinear fracture toughness parameters with thickness was studied in CORONA-5 titanium alloy having two different microstructures. The microstructure containing fine needles of alpha particles was found to have higher toughness than that containing globular alpha particles. This may be due to the difference in the shape of the particles or in the size of the particles.

Open PDF

Document Details

Document Type
Technical Report
Publication Date
Nov 05, 1981
Accession Number
ADA121900

Entities

People

  • H. Liebowitz

Organizations

  • George Washington University

Tags

Communities of Interest

  • Air Platforms

DTIC Thesaurus Topics

  • Alloys
  • Alpha Particles
  • Aluminum Alloys
  • Amplitude
  • Electron Microscopes
  • Experimental Data
  • Fatigue Tests (Mechanics)
  • Fracture (Mechanics)
  • Geometry
  • Grain Boundaries
  • Heat Treatment
  • Mechanics
  • Microscopy
  • Stress Intensity Factors
  • Test Methods
  • Thickness
  • Toughness

Fields of Study

  • Materials science

Readers

  • Astronomy/Astrophysics
  • Materials Science (Mechanical Engineering).