Caracterização micromecânica de propriedades de tenacidade à fratura de ligas de alumínio estruturais

• Ano de defesa: 2019
• Autor(a) principal: Trovato Neto, Euclydes
• Orientador(a): Couto, Antonio Augusto
• Banca de defesa: Vatavuk, Jan , Andrade, Arnaldo Homobono Paes de
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Presbiteriana Mackenzie
• Programa de Pós-Graduação: Engenharia de Materiais e Nanotecnologia
• Departamento: Escola de Engenharia Mackenzie (EE)
• País: Brasil
• Palavras-chave em Português: caracterização de tenacidade; mecânica de fratura; ligas de alumínio estruturais; métodos micromecânicos
• Área do conhecimento CNPq: CNPQ::ENGENHARIAS::ENGENHARIA CIVIL; CNPQ::ENGENHARIAS::ENGENHARIA CIVIL::ESTRUTURAS; CNPQ::ENGENHARIAS::ENGENHARIA CIVIL::ESTRUTURAS::ESTRUTURAS METALICAS; CNPQ::ENGENHARIAS::ENGENHARIA CIVIL::ESTRUTURAS::MECANICA DAS ESTRUTURAS
• Link de acesso: http://dspace.mackenzie.br/handle/10899/24256

This research work aims to investigate and apply numerical methodologies for the micromechanical characterization of fracture toughness parameters of structural aluminum alloys. It is taken into perspective that the growing use of aluminum structures systems, of multiple constructive types, makes it relevant and necessary to guarantee adequate levels of structural safety and reliability. For this purpose, strategic scientific and industrial research programs are devoted to investigations related to the characterization of materials properties and the mechanical behavior of structural aluminum alloys. It is pertinent to develop robust methodologies for evaluating characteristic toughness parameters for Critical Integrity Assessments, consistent with rheological patterns of these materials. Computational Mechanics methodologies were reviewed that admit representative formulations of the microstructural and micromechanical conditions intrinsic of aluminum alloys, to numerically assess J Integral toughness values (Rice, J.R.-1966). An experimental database of characteristic toughness parameters of AL-5XXX Aluminum-Magnesium alloys (DRDC, 2007) were employed: AL-5083 H321; AL-5086 H116 and AL-5383 H116, tested according (ASTM E 1820,2001) criteria. The Micromechanical Analysis Methodology (XIA, L. and SHIH, 1995) is applied to characterize thel fracture toughness parameter JIc (critical fracture onset) and uses computational cells to represent the distribution of microstructural defects. Dilatant Plasticity constitutive formulations (GURSON, A.L., 1981), and non-linear elasto-plastic rheological behavior (RAMBERG-OSGOOD, 1943) are considered. Through means of the WARP3D V 17.8.2 FEM System resources, both large scale (SSY-MBL) and finite-size test specimens of type (C (T)) discrete models were analysed. Visualization of geometry and results is achieved through the PARAVIEW system, defined with PYTHON features. Key results show that the micromechanical methodology applied leads to the characterization of the Integral J toughness parameters, and allowed to establish of experimental correlation with JIc tenacity characterization parameters. The numerical procedures allowed to obtain the calibration of micromechanical parameters, related with the microestutural voids index fo.