http://repositorio.ufc.br/handle/riufc/506 2026-04-06T03:34:31Z http://repositorio.ufc.br/handle/riufc/71210 Título: Propriedades mecânicas de filmes de quitosana reforçados com fibras de celulose Autor(es): Nunes, João Vitor da Silveira; Melo, Santino Loruan Silvestre de; Rios, Margarida Frota; Coutinho, Jaine Caboclo; Lima, Francisco Victor Rosa de; Deus, Ênio Pontes de Abstract: Chitosan is an artificial polymer obtained from chitin. This material allows to produce thin films with biodegradable and antibacterial properties. Its main applications are for packaging and the medical field. However, its low mechanical properties still limit its use, so there are several studies on the influence of additives on mechanical properties. The work consisted in the production of chitosan films with and without the addition of cellulose fibers to verify the influence on mechanical properties. Solutions of 1.5% w/v of chitosan dissolved in 1% v/v acetic acid were produced, with subsequent addition of glycerol and 10% of sisal fiber at 0.5mm in proportion to the mass of chitosan. The solutions were oven dried to produce the films. Tensile tests were realized in decaplicate following the ASTM D882-18 standard. The values of tensile strength and elongation at break went through a statistical analysis using the software Jamovi version 2.2.5. It was observed that the addition of fiber caused a significant increase in tensile strength from 2.69 ± 0.53 to 6.06 ± 0.95 MPa, but also causes a decrease in elongation from 29.8(28,6;30,8) to 14.1(12,9;14,4). Tipo: Artigo de Evento 2022-01-01T00:00:00Z http://repositorio.ufc.br/handle/riufc/71209 Título: Simulação da propagação de trincas por fadiga em ligas de alumínio aeronáutico sob sequências de cargas padronizadas Autor(es): Montezuma, Marcos Fábio Veríssimo; Deus, Ênio Pontes de; Rucher, Cassius Olívio Figueiredo Terra; Carvalho, Márcio Corrêa de Abstract: This work proposes to evaluate the effect of retardation and acceleration on crack propagation in aeronautical grade aluminum alloys, subject to a history of loading of constant and variable amplitudes, through numerical simulation, using real sequences of standardized loads. For the development of the model, the concepts of fracture mechanics and fatigue are used to create an algorithm, named Propag_Lameff, developed to evaluate the effect of delay and acceleration on crack propagation. The numerical results of the model are compared with experimental results produced in the laboratory. At the end of the work, this methodology may contribute to the construction of an open-source platform related to the phenomenon of fatigue, in order to provide independent analysis of closed programs that in generally they are paid and without the possibility of expanding their functionality by the user. This methodology can be used in several areas, in addition to the aeronautical industry, where the improvement in the development of new design criteria is necessary. The crack propagation delay mechanism allows the design criteria, considering fatigue, to be optimized and realistic, avoiding excessive safety margins in the design of a component or structure Tipo: Artigo de Evento 2022-01-01T00:00:00Z http://repositorio.ufc.br/handle/riufc/69322 Título: Avaliação da resistência à corrosão de dois aços alto manganês e o aço 9% níquel em solução de H2SO4* Autor(es): Flórez, Mauro Andrés Cerra; Vieira, Matheus de Lima; Guedes, Thiago César Souza; Araújo, Walney Silva; Silva, Marcelo José Gomes da Tipo: Artigo de Evento 2017-01-01T00:00:00Z http://repositorio.ufc.br/handle/riufc/69321 Título: Efeito da técnica da dupla camada sobre a microestrutura e tenacidade da ZAC do aço ABNT 4140 recuperado por soldagem Autor(es): Aguiar, Willys Machado; Farias, Jesualdo Pereira; Silva, Cleiton Carvalho Tipo: Artigo de Evento 2003-01-01T00:00:00Z