Patent ID: 7047786

Claim:
Tooling for working a structure to improve the fatigue strength at a selected location in said structure, said structure comprising a first surface, a second surface, and a body therebetween, said tooling comprising: a first indenter, said first indenter comprising a contacting end for engagement with and deformation of a pre-selected portion of said first surface of said structure to impart a residual stress profile in said body of said structure, and wherein said contacting end of said first indenter comprises a shaped surface profile substantially conforming to a dimple shape in said first surface of said structure produced by the application of a substantially uniform pressure profile on said pre-selected portion of said first surface of said structure, and wherein said contacting end of said first indenter further comprises a surface shape defined by the equation: u z = C ⁢ ( 4 ⁢ ( 1 - v 2 ) ) E ⁢ P m ⁢ a ⁢ ⁢ ∫ 0 π / 2 ⁢ 1 - a 2 r 2 ⁢ ( sin 2 ⁢ θ ) ⁢ ⁢ ⅆ θ wherein u z =normal displacement of a selected surface location of said contacting end of said indenter above a flat reference plane, v=Poisson's Ratio of the material comprising said workpiece; E=Elastic Modulus of the material comprising said workpiece; P m =contact pressure distribution that yields said workpiece; a=radius of the contacting end of said indenter; and θ, r=polar coordinates of a selected surface location on said contacting end of said indenter. C=a constant ranging from 1 to 110.