Abstract: The finite element model of the unsymmetrical tapered lug is built by using the finite element software ANSYS, the cosine-distributed load that is accordant with the practical situation, is applied on the hole as the boundary conditions. The stress intensity factor (SIF) expression of the symmetric tapered lug with a through crack along the hole is fitted by studying the effect of the dimensionless crack length (a/R1), the ratio of outer radius to inside radius (R2/R1) and the inside radius (R1) on SIF value. The result is validated by the corresponding residual strength test. The method can be used for solving stress intensity factors of lugs or similarity structures with different shapes, it provides a reference for damage tolerance design and assess of typical lugs structural in engineering.

Key words: Attachment lug, Cosine-distributed load, Damage tolerance design, Finite element method, Stress intensity factor