Effects of different structural parameters on the 7075-T651 aluminum alloy lug structure fatigue life

Lug structure is an important connection structure in aviation aircraft. However, fatigue cracks are easily generated during the service of the aircraft. Therefore, this study aims to explore the influence of different structural parameters on the fatigue life of the 7075-T651 aluminum alloy lug, using experimental and numerical methods to determine the effects of these structural parameters. Scanning electron microscopy was employed for fracture analysis, and three-dimensional finite element models were used to solve the holes edge stress distributions under peak load and stress concentration factor. The results indicate that the fatigue life of the lug increases with the increase in the extrusion projection area and the included angle of the outer edge, and the impact of the extrusion projection area on the fatigue life of the lug is greater than the angle of the outer edge, and the fatigue life of the lug does not change with the change of the chamfer at the bottom. The peak stress at the root of the lug hole becomes the main factor affecting the fatigue life of the lug, and the crack always expands along the net cross-section of each parameter lug.