Development of an Abaqus UMAT Subroutine for Predicting Ductile Fracture in Deep Drawing Based on the Brozzo Model

BACKGROUND The study aimed to analyse the models of ductile fracture and justify the choice of the most suitable one for modelling the deep drawing process. The study compared the main models of ductile fracture: Cockcroft & Latham, Brozzo, Oh, Johnson & Cook, Bai & Wierzbicki, Modified Mohr-Coulomb, Lou-Huh, Gurson-Tvergaard-Needleman and Lemaitre. MATERIALS AND METHODS In particular, the application of these models to the process of deep drawing was emphasised, and their advantages and limitations were identified. RESULTS The analysis determined that the Brozzo model is the most effective for predicting material behaviour under plastic deformation, as it provides an accurate assessment of damage accumulation through the integration of stresses and strains. This effectively predicts the moments of fracture during the deep drawing process. As a result, a specialised custom subroutine for Abaqus was developed that implements the Brozzo model fracture criterion. The introduction of this criterion into the software environment ensured accurate prediction of the material’s fracture initiation points. In addition, theoretical numerical modelling of the deep drawing process was conducted, which confirmed the high accuracy of predicting damage zones and the possibility of estimating the moment of part failure at different stages of deformation. The simulations showed that the Brozzo model allows for reliable estimation of plastic deformation and fracture zones, which is important for optimising sheet metal forming processes and improving product quality. CONCLUSION The obtained results confirmed the effectiveness of the applied model for calculating fracture under plastic deformation, which is of practical importance for optimising the technological processes of sheet metal forming.