Characterization of Metal Foil in Anisotropy Fracture Behavior with Dynamic Tests 2018-01-0108
Metal foil is a widely-used material in the automobile industry, which is not only the honeycomb barriers material, but also used as current collectors in Li-ion batteries. Plenty of studies proved that the mechanical property of the metal foil is quite different from that of the metal sheet because of the size effect on microscopic scale, as the metal foil shows a larger fracture stress and a lower ductility than the metal sheet. Meanwhile, the fracture behavior and accurate constitutive model of metal foil with the consideration of the strain rate effect are widely concerned in further studies of battery safety and the honeycomb. This paper conducted experiments on 8081-H18 aluminum foil, aiming to explore the quasi-static and dynamic tension testing method and the anisotropy mechanical behavior for the very thin foil. Two metal foil dog-bone specimens and 3 types of notched specimens are tested with a strain rate ranges from 2 × 10−4/s to 40/s and various stress states. It is shown that the metal foil has an obvious anisotropy behavior and the stress level increases with the strain rate. An anisotropic material model, which combined the Yld2000-2d plasticity model and the rate-dependent plasticity framework, is used to describe the mechanical behavior of the metal foil. Meanwhile fracture behavior of these metal foils are calibrated with an anisotropic fracture initiation model. The results of constitutive model reproduce the strain-rate effect and the anisotropy behavior of metal foil, which have a good agreement with the experimental data.