Fatigue justification for straightening parts with Flap Peening

Author:  S. E.D. Ramati
Source:  Conf Proc 2014: ICSP-12 Goslar, Germany (pgs.191-196)
Doc ID:  2014074
Year of Publication:  2014
Abstract:  
Flap peening is a form of shot peening that is very useful for rework of small areas. The Flap is also called self contained peening since the shot is bonded to the flap which enables use on assembled structures as the shot does not fly off in all directions. Shot peening is used for forming parts such as wing panels, and though the intensities are limited with the flap they are still high enough to enable straightening under certain circumstances. The fatigue improvement of the shot peening process is well documented but not so for flap peening. Recently a certain OEM questioned the flap straightening process inferring that the process will decrease part life. The common accepted view is that it will not degrade the material or part properties but the contrary is true it enhances fatigue life. The fatigue tests confirmed the accepted view. The paper will show results of fatigue testing of flap straightened aluminium sheets samples. In addition several interesting field applications will be shown of straightened parts that are flying