The Fatigue Crack Propagation Delay Behavior in 2024-T3 Aluminum Alloy Due to Single Overload/Underload Sequences

Abstract

The fatigue crack delay behavior due to single overload/underload sequences was studied in center crack panel specimens of 2024-T3 aluminum alloy. The applied loading consisted of constant amplitude loading, an applied overload immediately followed by an underload and then constant amplitude loading at the pre-overload level. The loading parameters investigated are the stress intensity ratios, overload level to maximum fatigue level, underload level to overload level, and minimum fatigue level to overload level. The results show that increasing the amount of underload decreases the number of delay cycles. Also, it is shown that the number of delay cycles is directly related to the minimum growth rate following the overload. The concept of crack closure is extended to include the effects of the overload/underload sequence. From this the maximum value of the opening stress intensity level and the minimum growth rate are determined. This is used to predict the number of delay cycles.

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Document Details

Document Type
Technical Report
Publication Date
Aug 01, 1975
Accession Number
ADA018860

Entities

People

  • A. C. Skat Jr.
  • B. M. Hillberry
  • William X. Alzos

Organizations

  • Purdue University

Tags

Communities of Interest

  • Air Platforms

DTIC Thesaurus Topics

  • Air Force
  • Alloys
  • Aluminum
  • Aluminum Alloys
  • Crack Propagation
  • Crack Tips
  • Engineering
  • Equations
  • Geometry
  • Government Procurement
  • Governments
  • Mechanical Engineering
  • Regression Analysis
  • Residual Stress
  • Stress Intensity Factors
  • Thickness
  • Three Dimensional

Readers

  • Applied Combinatorial Optimization and Logic Circuit Design.
  • Materials Science (Mechanical Engineering).