The Effect of Peening on the Fatigue Life of 7050 Aluminium Alloy

DSTO-RR-0208
Y470 X19 pocket
Peened
Previously
Non-peened
region
Repair as per
documentation.
Maintain on Safe Life
Determine depth <strong>of</strong> material
to be removed to ensure confident
removal <strong>of</strong> cracks, Figure 33
Based on NDI threshold
and FE analysis.
Requiring less than
500microns for Safe Life
Requiring greater than
500microns for Safe Life
Repair (full cut) as
per documentation.
Maintain on Safe Life
Repair (full cut) as
per documentation.
Maintain on Safe Life
Repair (cut to NDI
limit) Maintain on
Safety-by-Inspection
Figure 34: Summary <strong>of</strong> the proposed DSTO Y470 X19 pocket repair process. In the RAAF fleet the
X-19 pocket has not previously been peened. <strong>The</strong> 500µm (0.02 inch) LPI limit is based on
current AAP NDI limitations.
<strong>The</strong> complete details <strong>of</strong> this repair specification are present in a report by (Sharp, Barter and
Clark, 2000). <strong>The</strong> report allows the RAAF to assess the status <strong>of</strong> each aircraft and determine
future repair times or replacement times.
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