An uncoupled ductile fracture model considering void shape change and necking coalescence

In order to accurately describe the fracture behaviour of ductile metals in a wide range of stress states, based on the mechanism of void nucleation, growth, and coalescence during plastic deformation, an uncoupled isotropic ductile fracture model was established, which considered the combination of void shape change and void coalescence through internal necking. Firstly, the effect of the volume and shape changes on the fracture behaviour of the material was summarized and discussed, and the mechanism of interpore dimple shrinkage and consolidation during the void coalescence was studied. Secondly, the parameters of the proposed model are studied in detail to verify the flexibility of the new model. Then, the proposed ductile fracture model was used to construct the 3D fracture locus of AA 2024-T351, AISI 1045, Q460, Mg-Al-Zn-RE, and Ti-6Al-4V materials, and the predicted fracture strain values under corresponding stress states were compared with the experimental results of previous scholars. The effectiveness of the proposed new model is verified. Finally, to demonstrate the superiority of the proposed new model, the predicted results were compared with those of the widely used DF2016, MMC, and Hu models. The prediction results show that the new model has the highest precision compared to the other three. The void shape change and the void coalescence through internal necking play an essential role in the ductile metal fracture process, which should be fully considered.

Automated summary

Based on the mechanism of void nucleation, growth, and coalescence, this study established an uncoupled isotropic ductile fracture model that considered void shape change and void coalescence through internal necking. The flexibility and effectiveness of the proposed model were verified through parameter studies and comparison with experimental results. The new model showed superior precision compared to other widely used models.