Corrosion Fatigue Crack Growth Behavior at Notched Hole in 7075 T6 Under Different Biaxial Stress Ratios

Abstract

This thesis presents the results of a study to quantify the effects of biaxial loading on fatigue crack behavior in both air and saltwater (3.5% NaCl) environments from pre-cracked notched circular hole in a 7075-T6 cruciform specimen using a fracture mechanics approach. With stress ratio of R = 0.5, the crack growth behavior was investigated under fatigue loading with 0.5, 0, -0.5, and -1 biaxial stress ratio lambda. The crack propagation was monitored using optical microscopy. Finite Element Analysis was performed using the different stress ranges and stress ratios with various crack sizes to compute of stress intensity factors (delta K) at the crack tips. It was observed from the study that negative biaxiality has a very pronounced effect on the crack growth rate. The crack propagates faster with negative biaxiality and also the saltwater environment accelerates the crack propagation due to corrosion.

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Document Details

Document Type
Technical Report
Publication Date
Aug 18, 2016
Accession Number
AD1018249

Entities

People

  • Khalid A. Alghamdi

Tags

Communities of Interest

  • Air Platforms

DTIC Thesaurus Topics

  • Aircraft Equipment
  • Aircraft Industry
  • Aircrafts
  • Biaxial Stresses
  • Corrosion
  • Finite Element Analysis
  • Fracture (Mechanics)
  • Materials
  • Materials Science
  • Materials Testing
  • Mechanical Properties
  • Mechanical Working
  • Mechanics
  • Modulus Of Elasticity
  • Stress Corrosion Cracking
  • Stress Intensity Factors
  • Yield Strength

Fields of Study

  • Engineering

Readers

  • Materials Science (Mechanical Engineering).