Extended Gurson-Tvergaard-Needleman model considering damage behaviors under reverse loading

• Published in: International journal of mechanical sciences 2024-06, Vol.272, p.109196, Article 109196
• Main Authors: Wu, Hongfei, Zhang, Chenyang, Yang, Huachao, Zhuang, Xincun, Zhao, Zhen
• Format: Article
• Language: English
• Subjects: Compression-tension; Damage evolution; Ductile fracture; Extended GTN model; Reverse loading; Shear-reverse shear
• ISSN: 0020-7403; 1879-2162
• DOI: 10.1016/j.ijmecsci.2024.109196

•The GTN model is modified by considering the damage behaviors under reverse loading.•The microscopic damage evolutions are modified by two kinds of exponential function.•The preloading and loading sequence can affect the damage accumulation and fracture.•The predictive ability of ductile fracture under reverse loading is highly improved. Void nucleation, growth, deformation and coalescence are the main microscopic damage mechanisms for plastic deformation of sheet metals. To describe the effect of reverse loading on the microscopic damage accumulation and ductile fracture, the damage evolution equations in regard of void nucleation, void growth, shear void nucleation and shear deformation damage were modified. Through the further introduction of the combined hardening model, an extended Gurson-Tvergaard-Needleman (GTN) model was constructed in this study, to improve the predictive ability of ductile fracture under reverse loading conditions. Two typical reverse loading experiments including compression-tension and shear-reverse shear were performed. The number, size and shape of microscopic voids were qualitatively analyzed and compared through the microscopic observations, it is indicated that the preloading and loading sequence strongly affect the damage accumulation and the final ductile fracture, which is the microscopic damage mechanisms under reverse loading. The proposed GTN model was verified by the load responses and displacements at fracture (DAFs) of the conducted reverse loading experiments. The good agreement between numerical simulations and experimental results proves the rationality of the proposed GTN model and its accuracy to the prediction of ductile fracture under reverse loading conditions. [Display omitted]