Florida Group The impact of defects on the fatigue life of Aluminum 6061 and F.C. Brass.
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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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Transcript of Florida Group The impact of defects on the fatigue life of Aluminum 6061 and F.C. Brass.
Florida Group
The impact of defects on the fatigue life of Aluminum 6061
and F.C. Brass
Florida GroupAlriel Gali
Michael KnightLisa Mak
Johnathan Yoshimara
April 27, 2004Engineering 45
Materials Science
University of the PacificSchool of Engineering and Computer Science
3601 Pacific Ave. Stockton, CA 95211
Overview
Problem Definition Testing Discussion of Results Conclusions Acknowledgements
Background
What is fatigue?
Dynamic stresses
Why is it important?
Insidious failure
Problem Definition
Measure the impact of a defect on the fatigue life of Aluminum 6061 and F.C. Brass.
Hypothesis
Should fail at the defect or at the highest stress concentration
Testing Machine
What’s the machine?
RBF-200
How does it work?
Cantilever design
Picture of machine
Equations
Testing - Defect
Defect 1 – 0.089 inch diameter hole through center
Defect 2 – 0.089 inch diameter hole 0.25 inches from the center
Pictures - Defects
Results
What happened?
Reduced fatigue life
Failed at the defects
Pictures - after testing
Brass defect
Pictures - after testing
Aluminum Defect
S-N Curve - Brass
S-N Curve (Brass)
02468
10121416182022242628303234363840424446485052
0 15000 30000 45000 60000 75000 90000 105000 120000 135000
cycles to failure (N)
Str
es
s (
ks
i)
Control (Brass)
defect one
defect two
S-N Curve - Aluminum
S-N curve (Aluminum)
0
5
10
15
20
25
30
35
40
0 10000 20000 30000 40000 50000 60000 70000 80000 90000 100000
Cycles to failure (N)
Str
es
s (
ks
i)
Control (Alumn.)
defect one
defect two
Fractography
Crack initiation at the defect.
Fractography
Striations along with crack propagation
Fractography
Beachmarks
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.
