AN ELASTO-VISCOPLASTIC MODEL FOR HEXAGONAL CLOSED PACKED MATERIALS: FORMULATION AND NUMERICAL IMPLEMENTATION

AN ELASTO-VISCOPLASTIC MODEL FOR HEXAGONAL CLOSED PACKED MATERIALS: FORMULATION AND NUMERICAL IMPLEMENTATION

Wu, S.H.; Pires, F.M. Andrade; Santos, Abel D.; Rocha, A. Barata da

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Titanium alloys have widespread applications in defense and aerospace industries owing to its high performance mechanical properties, particularly its high strength to weight ratio[1, 2, and 5]. Due to their Hexagonal closed packed (HCP) crystallographic structure; they have anisotropic properties and high strength differential (SD) effects in tension and compression during deformation[3, 4]. In practical applications, titanium alloys might be subject to complex loading conditions, which may include the presence of various strain rates. Therefore, in order to study their visco-plastic mechanical behavior, the present contribution proposes an elastic-viscoplastic model for HCP materials by extending the Cazacu yield criteria with the widely used visco-plastic formulation proposed by Perzyna[9]. The new model is implemented in an implicit quasi-static finite element framework with a fully implicit integration scheme. The stress integration algorithm employs the closest point projection method (CPPM) combined with the line search method. Two benchmark tests are performed to study the material mechanical behavior of the Ti-6Al-4V alloy at various strain rates. The stability and accuracy of this model is analyzed.

Titanium alloys have widespread applications in defense and aerospace industries owing to its high performance mechanical properties, particularly its high strength to weight ratio[1, 2, and 5]. Due to their Hexagonal closed packed (HCP) crystallographic structure; they have anisotropic properties and high strength differential (SD) effects in tension and compression during deformation[3, 4]. In practical applications, titanium alloys might be subject to complex loading conditions, which may include the presence of various strain rates. Therefore, in order to study their visco-plastic mechanical behavior, the present contribution proposes an elastic-viscoplastic model for HCP materials by extending the Cazacu yield criteria with the widely used visco-plastic formulation proposed by Perzyna[9]. The new model is implemented in an implicit quasi-static finite element framework with a fully implicit integration scheme. The stress integration algorithm employs the closest point projection method (CPPM) combined with the line search method. Two benchmark tests are performed to study the material mechanical behavior of the Ti-6Al-4V alloy at various strain rates. The stability and accuracy of this model is analyzed.

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DOI: 10.5151/meceng-wccm2012-18093

Referências bibliográficas

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• [9] Plunkett, B., O. Cazacu, et al. (2008). Orthotropic yield criteria for description of the anisotropy in tension and compression of sheet metals. International Journal of Plasticity 24(5): 847-866.
• [10] Otto M.Heeres, Akke S.J.Suiker, Rene de Borst. A comparison between the Perzyna viscoplastic model and the consistency viscoplastic model. European Journal of Mechanics 21 (2002) 1-12
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Como citar:

Wu, S.H.; Pires, F.M. Andrade; Santos, Abel D.; Rocha, A. Barata da; "AN ELASTO-VISCOPLASTIC MODEL FOR HEXAGONAL CLOSED PACKED MATERIALS: FORMULATION AND NUMERICAL IMPLEMENTATION", p-702-714. In: In Proceedings of the 10th World Congress on Computational Mechanics [= Blucher Mechanical Engineering Proceedings, v. 1, n. 1]. São Paulo: Blucher, 2014.
ISSN 23580828, DOI 10.5151/meceng-wccm2012-18093