Finite Element Modeling for Orthogonal Machining of AA2024-T351 Alloy With an Advanced Fracture Criterion

Numerical modeling of the plastic deformation and fracture during the high-speed machining is highly challengeable. Consequently, there is a need for an advanced constitutive model and fracture criterion to make the numerical models more reliable. The aim of the present study is to extend the recent advanced static Lou-Yoon-Huh (LYH) ductile fracture creation to high strain rate and temperature applications such as machining. In the present work, the LYH static fracture creation was extended to machining conditions by introducing strain rate and temperature dependency terms. This extended LYH fracture criterion was calibrated over the wide range of stress triaxialities and different temperatures. Modified Khan-Huang-Liang (KHL) constitutive model along with the variable friction model was employed to predict the flow behavior of work material during the machining simulation. Damage evolution method was coupled to identify the element deletion point during the machining simulation. Orthogonal machining experiments were carried out for an aerospace-grade AA2024-T351 at cutting speeds varying between 100 and 400 m/min with the feed rates varying between 0.1 and 0.3 mm/rev. To assess the prediction capabilities of extended LYH fracture criterion, numerical simulations were also carried out using Johnson-Cook (JC) fracture criterion under all experimental conditions. Specific cutting energy, chip morphology, and compression ratio predictions were compared with the experimental data. Numerical predictions with coupled extended LYH criterion showed good agreement with experimental results compared to coupled JC fracture criterion.