Florida Group

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Florida Group

• The impact of defects on the fatigue life of
  Aluminum 6061 and F.C. Brass

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Florida Group

• Alriel GaliMichael KnightLisa MakJohnathan
  Yoshimara April 27, 2004Engineering
  45Materials ScienceUniversity of the
  PacificSchool of Engineering and Computer
  Science3601 Pacific Ave. Stockton, CA 95211

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Overview

• Problem Definition
• Testing
• Discussion of Results
• Conclusions
• Acknowledgements

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Background

• What is fatigue?
• Dynamic stresses
• Why is it important?
• Insidious failure

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Problem Definition

• Measure the impact of a defect on the fatigue
  life of Aluminum 6061 and F.C. Brass.

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Hypothesis

• Should fail at the defect or at the highest
  stress concentration

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Testing Machine

• Whats the machine?
• RBF-200
• How does it work?
• Cantilever design

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Picture of machine
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Equations
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Testing - Defect

• Defect 1 0.089 inch diameter hole through
  center
• Defect 2 0.089 inch diameter hole 0.25 inches
  from the center

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Pictures - Defects
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Results

• What happened?
• Reduced fatigue life
• Failed at the defects

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Pictures - after testing
Brass defect
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Pictures - after testing
Aluminum Defect
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S-N Curve - Brass
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S-N Curve - Aluminum
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Fractography
Crack initiation at the defect.
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Fractography
Striations along with crack propagation
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Fractography
Beachmarks
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Work Cited

• Al-Zubi, R. Poly Processing Inc. - personal
  communication, March-April 2004.
• Burmeister, Jeff. Assistant Professor and Program
  Director-personal communication, March-April
  2004.
• Pollard, Bob. In charge of machine shop -personal
  communication, March-April 2004.
• Weick, Brian. Associate Professor/Dept.
  Chair-personal communication, March-April 2004.