Abstract:Combined with tensile experimental data of 5083H111 aluminum alloy at a wide range of strain rates from 2×10-4 to 4×102s-1, the V-typed strain-rate effect of this aluminum alloy is analyzed. The strain-rate and strain dependence of the logarithmic strain rate sensitivity coefficient λ and tangent modulus Et are discussed. Then, a dynamic constitutive model is established to describe the dynamic tensile behavior of 5083H111 aluminum alloy at a range of lower and middle strain-rates by modifying the Johnson-Cook model. The model reflects the V-typed strain-rate effect of tensile deformation of the aluminum alloy at researching strain-rates, and the predicted results of the proposed model are in good agreement with the experimental ones. Furthermore, based on the logarithmic strain-rate sensitivity coefficient β of failure strain, a new equation to predict the tensile failure strain of the alloy is formulated, and the predicted results are basically consistent with the experimental ones.