On the Fracture Behavior of Necked Double Shear Lugs for Aircraft Applications
Sprache des Vortragstitels:
ACEX2019 - 13th International Conference on Advanced Computational Engineering and Experimenting
Sprache des Tagungstitel:
This contribution investigates the fracture behavior of double shear lugs with spherical bearings subjected to axial loading. The focus is on specific shapes, so-called waisted or necked lugs. These structural components used in aircraft interior are prone to fatigue loads. Therefore, a detailed knowledge of their fatigue properties and fracture behavior is of great importance for safety.
Three different sizes of necked double shear lugs made of aluminum 2024-T351 and steel 17-4 PH were tested using multiple cyclic constant amplitude loadings. Measurement data were used to identify the number of cycles to crack initiation and final fracture. Furthermore, fatigue tests showed that cracks initiate either at the inside or outside surface of necked lugs depending on the load amplitude, lug size and material.
Numerical simulations using both conventional finite element method (FEM) and extended finite element method (XFEM) were made to calculate the stress intensity factors (SIFs) for multiple crack lengths of straight and necked double shear lugs. Calculated SIFs for straight lugs fit well to SIFs reported in literature. SIFs of inside and outside cracks of necked lugs have crossing trends with respect to crack length, which could have an influence on the fracture behavior observed in fatigue tests.