Enhanced Constitutive Model for Aeronautic Aluminium Alloy (AA2024-T351) under High Strain Rates and Elevated Temperatures

Abstract

Success of the numerical simulations depends on the accuracy of the material constitutive relations. Most of the ductile materials exhibit increased strain rate sensitivity at higher strain rates (> 103 s−1) compared to low and medium strain rates. Meanwhile, plastic deformation of any ductile material under high strain rate conditions results in heat generation due to plastic work. Hence, a reliable constitutive model should be able to predict the accurate thermo-mechanical response of the material over a wide range of strain rate loading conditions. In the present work, an enhanced constitutive model for high strain rate and elevated temperature is proposed. For calibration purpose, the stress-strain response of AA2024-T351 is studied under quasi-static and dynamic loading conditions using uniaxial compression and split Hopkinson compressive pressure bar (SHPB) respectively at various temperatures. A threshold strain rate value is identified and used to improve the prediction capabilities of the present model. Later, the proposed model is compared with Johnson-Cook (JC) and Khan-Huang-Liang (KHL) models using the different statistical parameters. This analysis revealed the improved stress-strain prediction capability of the proposed model compared to the others.