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

Contents
1. INTRODUCTION ............................................................................................................... 1
2. REVIEW ........................................................................................................................2
2.1 General........................................................................................................................ 2
1.2 F/A-18 <strong>Peening</strong> Processes ........................................................................................ 6
3. AMRL RESULTS ............................................................................................................... 14
3.1 Overview <strong>of</strong> <strong>Peening</strong> Research Programs .......................................................... 14
3.2 Early research - definition <strong>of</strong> potential problem .............................................. 14
3.2.1 Assessment <strong>of</strong> RAAF aircraft................................................................. 21
3.2.2 Surface roughness/residual stress measurement............................... 22
1.1.3 Summary <strong>of</strong> AMRL <strong>Peening</strong> Specification .......................................... 26
1.3 Rework <strong>Peening</strong> Research..................................................................................... 26
1.3.1 Different rework process comparisons................................................. 27
1.1.2 F/A-18 fleet rework simulation............................................................. 33
1.1.3 Summary <strong>of</strong> AMRL Rework <strong>Peening</strong> Specification............................ 35
1.4 <strong>Peening</strong> Life Improvement Factor (LIF).............................................................. 35
1.5 Fleet Applications Research.................................................................................. 37
1.5.1 Y470 Crotch Repair Program ................................................................. 37
1.5.2 Fleet Y470.5 X19 Pocket Repair program ............................................. 40
1.1.3 IFOSTP Fatigue Tests .............................................................................. 45
4. DISCUSSION..................................................................................................................... 46
5. CONCLUSION................................................................................................................... 48
6. ACKNOWLEDGMENTS ................................................................................................. 52
APPENDIX A: ...................................................................................................................... 53
6.1 Spectrum Details..................................................................................................... 53
6.2 Almen Definition.................................................................................................... 53
6.3 Saturation Curve ..................................................................................................... 54
7.4 Surface Roughness.................................................................................................. 56