Patent ID: 7089124

Claim:
A method of analyzing structural stress σ s in a localized fatigue-prone region of a structure from a representation of the structure, said method comprising: determining a through-thickness stress distribution σ x (y) along a selected cross section of said structure, wherein a localized fatigue-prone region lies adjacent to said selected cross section, and wherein said stress distribution σ x (y) is determined from said representation of said structure; determining a first component σ M of said structural structural stress σ s in said localized fatigue-prone region by performing an operation having a result substantially equivalent to a result of the following first integration σ M = 1 t ⁢ ∫ o t ⁢ σ X ⁡ ( y ) ⁢ ⅆ y where σ x (y) represents said through-thickness stress distribution and t corresponds to the thickness of said structure in said selected cross section; determining a second component σ B of said structural stress σ s in said localized fatigue-prone region by performing an operation having a result substantially equivalent to a solution of the following equation for σ B ( t 2 2 ) ⁢ σ M + ( t 2 6 ) ⁢ σ B = ∫ 0 t ⁢ σ x ⁡ ( y ) ⁢ y ⁢ ⅆ y + δ ⁢ ∫ 0 t ⁢ t xy ⁡ ( y ) ⁢ ⅆ y where y corresponds to a position along said selected cross section, t corresponds to the thickness of said structure in said selected cross section, δ is a value defined in said representation of said structure, σ x (y) represents said through-thickness stress distribution, and τ xy (y) represents a through-thickness shear stress distribution of said structure; and calculating said structural stress σ s by combining said first component σ M of said structural stress and said second component σ B of said structural stress.