Preform
Mostrando 1-12 de 27 artigos, teses e dissertações.
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1. Some aspects on geometric and matrix work-hardening characteristics of sintered cold forged copper alloy preforms
Powder metallurgy (P/M) material subjected to plastic deformation results into densification, however the extended deformation would not only enhance the densification also supplements the strain hardening. Unlike fully dense material that would only undergo strain hardening while plastic deformation, the P/M material leads to pore closure as well; this phen
Mat. Res.. Publicado em: 22/10/2013
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2. Experimental RTM manufacturing analysis of carbon/epoxy composites for aerospace application
The success of manufacturing composite parts by liquid composite molding processes with RTM depends on tool designs, efficient heat system, a controlled injection pressure, a stabilized vacuum system, besides of a suitable study of the preform lay-up and the resin system choice. This paper reports how to assemble a RTM system in a laboratory scale by specify
Mat. Res.. Publicado em: 05/07/2013
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3. Estudo da influência da força de corte em usinagem a verde nas propriedades mecânicas de cerâmicas sinterizadas / Influence of the cutting force of green machining on the mechanical properties of sintered ceramics
The present study deals with the measurement forces of green machining ceramics and their correlation with the mechanical properties after sintering. The green machining is employed in crude compacts either to check raw formats without compromising the extreme dimensional accuracy or to obtain a preform prior to finish machining after sintering, extensively
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 13/01/2012
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4. Three-dimensional numerical modeling of RTM and LRTM processes
Resin Transfer Molding (RTM) is a manufacturing process in which a liquid resin is injected into a closed mold pre-loaded with a porous fibrous preform, producing complex composite parts with good surface finishing. Resin flow is a critical step in the process. In this work, the numerical study of the resin flow in RTM applications was performed employing a
Journal of the Brazilian Society of Mechanical Sciences and Engineering. Publicado em: 2012-06
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5. Some aspects of barreling in sintered plain carbon steel powder metallurgy preforms during cold upsetting
The present research establishes a relationship of bulged diameter with densification and hydrostatic stress in forming of sintered iron (Fe) powder metallurgy preforms cold upset under two different frictional conditions, namely, nil/no and graphite lubricant condition. Sintered plain carbon steel cylindrical preforms with carbon (C) contents of 0, 0.35, 0.
Materials Research. Publicado em: 15/03/2012
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6. Strain hardening behaviour in forming of sintered iron-0.35% carbon powder metallurgy preform during cold upsetting
A complete experimental investigation on the instantaneous strain-hardening behaviour of powder metallurgy preforms of Fe-0.35%C was carried out. The strain hardening behaviour of the above-mentioned P/M sintered steel preforms with aspect ratio of 0.4 and 0.6, respectively, under triaxial stress state condition was determined by cold upsetting under nil/no
Materials Research. Publicado em: 28/10/2011
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7. Um novo método para síntese de vidros fotônicos baseado na sinergia entre as técnicas VAD e ALD / A new method for synthesis of photonic glasses based on the synergy between VAD and ALD techniques
This study aimed to establish a new method for synthesis of photonic glasses through the synergy of Vapor-phase Axial Deposition (VAD) and Atomic Layer Deposition (ALD) techniques. Having the intention to obtain a completely transparent material containing a uniform distribution of dopant element both radial and axial position. In the first stage of this stu
Publicado em: 2011
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8. Modeling elastic and thermal properties of 2.5D carbon fiber and carbon/SiC hybrid matrix composites by homogenization method
Abstract: Advanced carbon fiber hybrid carbon-ceramic matrix composites are realizing their potential in many thermostructural components for aerospace vehicles. This work presents ab-initio predictions of elastic constants and thermal properties for 2.5D carbon fiber reinforced carbon-silicon carbide hybrid matrix composites, by using the homogenization tec
J. Aerosp. Technol. Manag.. Publicado em: 2010-08
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9. Processo automatizado de fabricação de preformas aplicado a fibras opticas mantenedoras de polarização para sensores fotonicos / Automated preform fabrication method applied to polarization-maintaining fibers for photonic sensors
Fibras ópticas mantedoras de polarização (PMF) permitem preservar o estado de polarização da luz através de uma elevada birrefringência, induzida, por exemplo, com a nãocircularidade do núcleo, e são utilizadas em sistemas ópticos coerentes e na fabricação de sensores, lasers e giroscópios ópticos. Entretanto, os métodos de produção de pref
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 06/08/2009
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10. Preform map for mild steel upsetting and its experimental verification
In upsetting process, an initial block of metal (billet) is compressed between two or more dies to produce a complex part. Geometry of the final product is strongly dependent on the shape of initial work piece as well as on the perform shapes at each of the subsequent forming stages. Design of the optimum preform for near net shape manufacturing is a crucial
Journal of the Brazilian Society of Mechanical Sciences and Engineering. Publicado em: 2009-09
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11. Fabricação de malha de trama utilizada como pré-formas na indústria de compósitos e avaliação das propriedades mecânicas
In the manufacture of composite, textile materials are being used as reinforcement. Generally, the combination of the matrix with the textile material in the form of fibres or yarns is used depending on their distribution in the web. In the present work, in place of fibres or yarns, a knitted structure in the form of the final product which is defined as pre
Publicado em: 2009
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12. Influence factors on forging die wear of automotive connecting rods / Fatores de influencia no desgaste de matrizes de forjamento a quente de bielas automotivas
A significant part of forgings prices is due to costs from reworks of forging dies because of superficial failures on their surfaces. In quest of a higher competitiveness in terms of prices and production times, it is necessary to understand the mechanisms of die failure to increase its working life, avoiding risk situations and a possible total failure of t
Publicado em: 2009