Fast-to-Compute Weakly Coupled Ductile Fracture Model for Structural Steels

Ductile fracture in metals can be simulated either by coupled or by uncoupled fracture models. Although the coupled models simulate the gradual loss of strength resulting from the initiation of the damage attributable to microvoid nucleation, growth and coalescence, the uncoupled models can describe critical the conditions under which ductile fracture initiates. Even though the coupled models can completely characterize the ductile damage process, calibration of these models is difficult and their computational implementation is expensive when compared with the uncoupled fracture models. This study is concerned with development of a fracture model that can simulate the ductile fracture process in steels like coupled models with the computational efficiency of the uncoupled models. To this end, a weakly coupled fracture model that can efficiently simulate the ductile fracture process is introduced. The weakly coupled model is proposed based on a micromechanical void growth model and is calibrated using the experimental data from notched steel specimens. The weakly coupled fracture model is successfully used to simulate failure resulting from ductile fracture in specimens made up of different batches of ASTM A992 steels and in specimens made up of ASTM A572 steels.