Patent ID: 7516673

Claim:
A method of analyzing structural stress σ s in a fatigue-prone region of a structure, said method comprising: determining a stress distribution σ x (y) along a selected cross section of said structure; determining a first component σ M of said structural stress σ s in said fatigue-prone region by performing an operation having a result substantially equivalent to a result of the following first integration σ M = 1 t ⁢ ∫ 0 t ⁢ σ X ⁡ ( y ) ⁢ ⁢ ⅆ y where σ x (y) represents a through-thickness stress distribution and t corresponds to a thickness of said structure; determining a second component σ B of said structural stress σ s in said 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 or, its mathematical equivalent σ B = 6 t 2 ⁢ ∫ 0 t ⁢ σ X ⁡ ( y ) ⁢ ( y - t 2 ) ⁢ ⁢ ⅆ y where y corresponds to a position along said selected cross section, t corresponds to said thickness of said structure, and σ x (y) represents said through-thickness stress distribution; 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.