Analysis of fracture criteria for 7050 aluminum alloy with different geometries based on the elastic strain energy density

• A fracture criterion is proposed to predict fracture of structural parts.
• A normalized damage variable DN is defined to represent the ductile damage.
• Structural parts of different geometries are studied by FEM and experiment.
• Fracture and damage are studied quantificationally based on ESED.

A fracture criterion based on the elastic strain energy density (ESED) is used in consideration of the effect of structural geometry and mechanical properties, including the ultimate tensile strength, stress intensity factor, stress concentration factor and specific surface energy. A normalized damage variable DNDN is defined to represent the ductile damage within the plastic deformation zone. To investigate the fracture behavior using the energy fracture criterion, structural parts of different geometries are studied by testing 7050-T7451 aluminum alloy standard specimens: standard tensile specimen, hole specimen and compact tension specimen. Finite element models are established for each specimen, and the corresponding experimental processes are simulated. The numerical results are consistent with the experimental results. By comparing and analyzing the results, the effects of different geometries on the deformation damage and fracture process, the energy condition of crack propagation, fracture orientation and fracture morphology are discussed.