Research on dynamic constitutive model and fracture criterion of 6082-T6 aluminium alloy

Abstract

In this study, the mechanical properties of materials under different stress states, strain rates, and temperatures were tested, and a variety of material mechanical properties were obtained. The modified Johnson-Cook (JC) constitutive model and ASCE-MJC fracture criterion with Lode angle correction were calibrated. A 6082-T6 aluminium alloy projectile with a diameter of 5.95 mm was used in performing the Taylor impact test with an impact velocity ranging from 156.548 to −417.216 m/s. Mushrooming and shear cracking were observed during the test. A finite element model (FEM) corresponding to the test was established using the finite element software ABAQUS, and the model was used to predict the ductile fracture behaviour of the projectile. Through a comparison of experiments and parallel simulations, the ASCE-MJC fracture criterion was used to predict a very close fracture mode of the projectile. This proves the validity of the calibrated dynamic constitutive model and the fracture criterion. After comparing the finite element simulation results based on the classic JC fracture criterion prediction, it was found that the ASCE-MJC fracture criterion can better predict the ductility of 6082-T6 aluminium alloy, indicating that the fracture behaviour of the material has a significant Lode correlation. This improvement was verified. The validity of the modified JC constitutive model and ASCE-MJC fracture criterion in predicting the dynamic mechanical properties and fracture behaviour of the 6082-T6 aluminium alloy was also verified.