Experiments and simulations on tensile properties and fracture toughness of 7050-T7451 aluminum alloy hole specimens

The experiment and the simulation of the tensile properties and the fracture toughness of 7050-T7451 high strength aluminum alloy hole specimens for aircraft were conducted. The plastic dissipation energy of the crack tip associates tensile properties with fracture toughness K_IC, which can be quantificationally calculated through the tensile parameters. The distribution of the deformation zone and the zone proportion of plane stress and plane strain were characterized by parameter Z, which is determined by the geometry of the hole specimen. The research shows (1) Z parameter is associated with the K_IC of materials and components, and reflects the influence of the specimen geometry and hole size on the K_IC of components; (2) K_IC of the specimen is sensitive to the hole size perpendicular to the tensile direction, and decreases with the increase of the size; (3) the strength indexes such as yield stress and ultimate tensile strength are affected mainly by the hole size perpendicular to the tensile direction, and are almost irrelevant to the change of the hole size along the tensile direction, but the elongation is on the contrary.