Effect of Welding Flaws on the Fatigue Life of High Strength Steel Structures

Master's Thesis
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Abstract

The use of a welded high strength low alloy steel for an aerospace application involving high cycle fatigue was investigated. Welded specimens were fabricated and investigated under static and dynamic loading. The fatigue behavior of welded specimens was shown to vary significantly from unwelded specimens as expected, but also varied based on the type(s) of welding flaws detected by radiography. LEFM principles and crack growth parameters from steels with similar microstructures were used to model fatigue crack propagation in specimens with sharp flaws. The model was able to reasonably predict the fatigue life for these specimens. After the model was calibrated, specimens with internal pores were also studied in order to separate regimes of crack initiation and propagation during the fatigue lifetime. In specimens with only porosity flaws, the mean initiation life was over 60% of the total fatigue life, showing the benefit of removing sharp flaws from welds.

Attributes

Attribute NameValues
URN
  • etd-12072007-142658

Author Brian J. Shula
Advisor Ryan Roeder
Contributor Timothy Ovaert, Committee Member
Contributor Steven Schmid, Committee Member
Contributor Ryan Roeder, Committee Chair
Degree Level Master's Thesis
Degree Discipline Aerospace and Mechanical Engineering
Degree Name MSME
Defense Date
  • 2007-11-28

Submission Date 2007-12-07
Country
  • United States of America

Subject
  • crack growth

  • fatigue

  • welding flaws

Publisher
  • University of Notre Dame

Language
  • English

Record Visibility and Access Public
Content License
  • All rights reserved

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