A Micro-Macro mixed GTN-MMC model to study plasticity and fracture of AISI 4340 steel

•The classical GTN plasticity model is extended to include Lode angle dependency on matrix plasticity.•It is proved that a constant value of total microvoid volume fraction at fracture is insufficient to predict fraction initiation for plane strain specimens.•Combining with MMC fracture model, a new analytical solution of total microvoid volume fraction at fracture (GTN-MMC) is derived.•The micro–macro combined GTN-MMC model is capable of accurately simulating all 29 specimens made of AISI 4340 steels under three heat treatments.