Titre:	Influence of small defects on the fatigue limit of 304L stainless steel : axial-torsional experiments and modeling
Auteur(s):	Dias, Artur Lopes
Orientador(es)::	Castro, Fábio Comes de
Assunto::	Engenharia mecânica
Data de defesa::	6-mar-2020
Référence bibliographique:	DIAS, Artur Lopes. Influence of small defects on the fatigue limit of 304L stainless steel: axial-torsional experiments and modeling. 2020. 46 f., il. Dissertação (Mestrado em Ciências Mecânicas)—Universidade de Brasília, Brasília, 2020.
Abstract:	The influence of small defects on the fatigue limit of 304L stainless steel is investigated in this work. Fully reversed axial-torsional fatigue tests were carried out at room temperature on specimens containing a cylindrical defect with √area = 400 μm. The loading conditions used in the tests were: axial, torsional, in-phase, 90º out-of-phase, and square-shape. In all tests, nonpropagating cracks in the vicinity of the defect were not observed after 2 × 106 cycles (run-out condition). The absence of non-propagating cracks indicates that the threshold condition for crack initiation, instead of crack propagation, determines the fatigue limit of 304L stainless steel containing the defect type investigated. Crack orientation in the vicinity of the defect was measured for the tests conducted just above the fatigue limit. A critical plane fatigue criterion for metals containing small defects, which was recently developed at the University of Brasilia, was evaluated using the new test data for 304L stainless steel. The differences between estimated and observed fatigue limits were within a range of 11 to 15% when the model was calibrated using the Murakami–Endo expression for the uniaxial fatigue strength. Calibration of the model using the experimentally measured uniaxial fatigue strength yielded fatigue limits differing -2 to 3% from the observed values. The overall good agreement between estimated and observed crack angles suggests that the cracking behavior of 304L stainless steel containing a small defect is primarily governed by normal stresses (Mode I failure).
metadata.dc.description.unidade:	Faculdade de Tecnologia (FT) Departamento de Engenharia Mecânica (FT ENM)
Description:	Dissertação (mestrado)—Universidade de Brasília, Faculdade de Tecnologia, Departamento de Engenharia Mecânica, 2020.
metadata.dc.description.ppg:	Programa de Pós-Graduação em Ciências Mecânicas
Licença::	A concessão da licença deste item refere-se ao termo de autorização impresso assinado pelo autor com as seguintes condições: Na qualidade de titular dos direitos de autor da publicação, autorizo a Universidade de Brasília e o IBICT a disponibilizar por meio dos sites www.bce.unb.br, www.ibict.br, http://hercules.vtls.com/cgi-bin/ndltd/chameleon?lng=pt&skin=ndltd sem ressarcimento dos direitos autorais, de acordo com a Lei nº 9610/98, o texto integral da obra disponibilizada, conforme permissões assinaladas, para fins de leitura, impressão e/ou download, a título de divulgação da produção científica brasileira, a partir desta data.
Collection(s) :	Teses, dissertações e produtos pós-doutorado

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