Dissertações em Engenharia Mecânica (Mestrado) - PPGEM/ITEC
URI Permanente para esta coleçãohttps://repositorio.ufpa.br/handle/2011/2342
O Mestrado Acadêmico pertence ao Programa de Pós-Graduação em Engenharia Mecânica (PPGEM) do Instituto de Tecnologia (ITEC) da Universidade Federal do Pará (UFPA).
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Navegando Dissertações em Engenharia Mecânica (Mestrado) - PPGEM/ITEC por Orientadores "FUJIYAMA, Roberto Tetsuo"
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Item Acesso aberto (Open Access) Colagem de junta de madeira com adesivo epóxi(Universidade Federal do Pará, 2010-02-08) CARNEIRO, Ruth Pereira; FUJIYAMA, Roberto Tetsuo; http://lattes.cnpq.br/3165747089941318This work has as objective of making, to test and to compare the glued joints of butt, scarf and finger with three species of wood of different densities. The collage of the wood makes possible the use of pieces and surpluses of wood that are usually discarded, could minimize the cut of a lot of trees, be of the nature or of planned planting. The methodology of production of the joint, it was established with base in indications described in Brazilian norms. Macroscopic observation of the wood it was accomplished, for confirmation of your species. After established the dimension of the joints they were made bodies of proof, using the adhesive Compound Adhesive of epoxy base and wood Angelim-pedra, Jatobá and Tauari, acquired in wood deposit in the city of Ananindeua-Pa. With relationship the characterization of the adhesive, it was verified through the traction tests that has good mechanical resistance. After collages of the joints it was accomplished traction tests to determining the resistance of the glued joints. The glued joints performance it was evaluated in function of the relationship among the values of resistance to traction of the solid wood and the values of resistance to traction with glued wood and rupture way. In agreement with the results it was observed that the glued joints scarf they presented excellent resistance to traction, very close of the resistance of the solid wood; it was also noticed the good acceptance of collage of the wood Jatobá. With relationship the quality of the adhesion, the glued joints of butt and finger, therefore they presented adhesive rupture. The experimental results obtained indicate a good agreement among the theoretical models to evaluate the resistance to the traction and the qualification of the glued joints.Item Acesso aberto (Open Access) Comportamento mecânico de material compósito de matriz poliéster reforçado por sistema híbrido fibras naturais e resíduos da indústria madeireira(Universidade Federal do Pará, 2008-02-29) RODRIGUES, Jean da Silva; FUJIYAMA, Roberto Tetsuo; http://lattes.cnpq.br/3165747089941318In this work, composite materials of polyester matrix reinforced by short sisal fiber, by residue of wood and by hybrid system for sisal / residue of wood, arranged randomly, were produced using the minimum stages of technology processing in the productive step, with views to produce a composite material easy technically to produce. The polyester matrix used was a pre-accelerated tereftálica with cobalt naftenato and cured at room temperature with methyl ethyl ketone peroxide (MEK) in different proportions in relation to the resin, 0.33%, 1.66%, 3.33% and 5.00% by volume in order to evaluate the influence on mechanical properties. The sisal fibers were manually cut in lengths of 5, 10 and 15 mm and used in the way purchased and surface untreated. The residue of wood powder was used of maçaranduba wood. The composites were produced by manual moulding, without pressure and room temperature. Specimen were manufactured for evaluated matrix, composites reinforced by sisal, ranging of the length of the fibres, composites reinforced by maçaranduba residue and strengthening of hybrid composites, sisal / wood residue, in different proportions of the constituents. Mechanical properties were evaluated by tests of traction and Charpy impact and the areas of fracture generated were evaluated by scanning electron microscopy in order to correlate aspects of fracture with the mechanical properties. It was determined the specific mass of each series of specimen of each manufactured, and the volume fraction of the composite material. The results showed that the increase in the length of the sisal fiber, tensile strength and impact of composites has been increased, reaching the composite of sisal fibre, 15 mm, the best performance with the specimen series tested. The heterogeneity of size maçaranduba residue was negative effect on the mechanical properties of composites. The hybrid composites materials sisal / wood residue with higher content of fibers elevated in 80% of the mechanical properties obtained for the composite material reinforced only by sisal fiber.Item Acesso aberto (Open Access) Compósito de argamassa de cimento reforçada por fibra de sisal com entalhe definidos: caracterização mecânica e mecanismo de falha(Universidade Federal do Pará, 2010) PERES, Maria das Neves Pontes Barata; FUJIYAMA, Roberto Tetsuo; http://lattes.cnpq.br/3165747089941318In this work, we developed a new composite material using as a matrix of cement mortar reinforced with sisal fibers to 1% by weight, which were manually cut into lengths of 15 mm and 25 mm used without surface treatment using the lowest possible level of technological processes in manufacturing steps. The research was conducted to study the mechanisms of failure of this new material. The composites were produced with manual molding using immersion vibrator for better densification. Specimens were fabricated of the pure base and with the composites with sisal fiber, with pre-defined slots of 1.7 mm, 3,0 mm and 5,0 mm. The mechanical properties were evaluated by a bending test at three points and correlated with the fractographic appearance made in the Scanning Electron Microscope. The results showed that the presence of sisal fibers, embedded in cement paste,plastic shrinkage caused restriction of fresh mixture, possibly due to high water absorption capacity of fibrous reinforcement, an increase in mechanical strength and increased toughness of the composite over the base between the series of notches, decreasing the tendency to sudden fracture.Item Acesso aberto (Open Access) Fabricação e caracterização de material compósito de resina poliéster reforçada por tecido de fibra de tururi extraído da palmeira de ubuçu (Manicaria saccifera)(Universidade Federal do Pará, 2011-04-20) DUARTE, Cláudio; FUJIYAMA, Roberto Tetsuo; http://lattes.cnpq.br/3165747089941318The proposition of this work is to present and characterize a composite material produced with a polymeric matrix reinforced with natural fibers. The matrix is an insaturated teraftalic polyester pre -accelerated with the commercial name of Denverpoly 754 and the peroxide of MEK (Butanox M-50 ) as a catalyst in a proportion of 0,33% in volume. The natural fiber used was the “tururi”, obtained in the Marajó region, in the municipalite of Muaná. This fiber was submitted to two types of aperture in the transversal axis, in a proportion of 50% and 100% of the original width. The fabrication method of the composite was made through a manual lamination process (hand lay up) using a controlled pression by weights previously quantified. Phisycal, mechanical and microscopic characteristics were obtained for the fiber and the composite material , and in this way , the traction resistence, specific mass, weight of the fabric , mass fraction and microscopic image before and after the traction tests for the fiber fabric were made, and tests of traction for the composite material. The fabric of tururi, has shown a traction resistence of 29,95 MPa (without aperture), 12,27 MPa (aperture of 50%) and 9,38 MPa (aperture of 100% ). The aperture produces a reduction of the traction the resistence of the tururi fabric, and consequently reducing the traction resistence of the material. The weight of the fabric was reduced with the aperture. The mass fraction of the fabric of the composite was 14,39%(without aperture), 9,35 % (aperture of 50%) and 7,19% (aperture f 100%). The traction resistance was of 35,76 MPA (withot perture), 19,01 (50% aperture) and 16,8 MPa (100% aperture). The mechanical resistence has shown values much like those encountered in the literature for composites reinforced with natural fibers. The images obtained with swapping electronic microscopie, validated the mechanical properties obtained for each situation of the material and fibers.Item Acesso aberto (Open Access) Laminado de madeira reforçado com fibras naturais(Universidade Federal do Pará, 2013) SARAIVA, Marcelo Pires; FUJIYAMA, Roberto Tetsuo; http://lattes.cnpq.br/3165747089941318Towards the implementation of renewable natural resources of the Amazon, between these natural fibers. This paper presents the proposed fabrication and caracterization of wooden laminated matriz composites reinforced with polyester and natural fibers. The matrix is an unsaturated and pre-accelerated terephthalic polyester obtained commercially (Duverpoly 754) and a peroxide curing agent MEK (BUTANOX M-50) at a rate of 0.33 % vol. The natural fibers used for each sample of manufactured laminate were Tururi fiber tissue, sisal fibers and defibrated curauá and wood laminates known as Imbuia. The Turui tissue used with reinforcement was used in two ways: without opening and 100% opening relative to the original width. The curauá and sisal fibers were cut into lengths of 50 mm in the form of pre-preg. The manufacture of the laminated material was done by hand lay-up following controlled pressure through a hydraulic press with a constant pressure of 2 ton. Mechanical and microscopic characteristic were obtained for wood laminates. The wood laminates were assayed having two orientations of 90° and 0° of fiber orientation. The laminate of 0° degree showed the best result with a value corresponding to 35, 64 (MPa) compared to the value of 0,40 (MPa) of the lamina 90°. The tests of the laminates made of wood/Tururi without opening, wood/Tururi with opening 100%, wood/sisal fiber length of 50 mm, wood/curauá fiber length of 50 mm, wood/wood with an orientation of 90 ° the direction of the fibers, respectively achieved the following results in the Attraction tests: 61,33 (MPa), 57,27 (MPa), 49, 27 (MPa), 53, 76 (MPa) and 68, 29 (MPa), being that the laminate / wood presented the best results and lower mechanical strength was recorded for the wood laminate reinforced with sisal fibers. The images obtained in scanning electron microscopy corroborate the mechanical properties obtained for each situation of the manufactured material and fiber.Item Acesso aberto (Open Access) Material compósito de matriz frágil reforçado com fibras naturais de sisal e malva: caracterização e correlações das propriedades e mecânicas(Universidade Federal do Pará, 2010-12-22) MARTINS NETO, Sandoval Ferreira; FUJIYAMA, Roberto Tetsuo; http://lattes.cnpq.br/3165747089941318The purpose of this thesis is evaluate the mechanical behavior of cementitious matrix composites reinforced with sisal fibers and mauve, and correlate the material’s behavior with variations in the fibers types and lengths. The base material used in the manufacture of the composite was cement, sand, water and sisal fibers and mauve. It was used the trace 1: 2: 0,5 (cement, sand and water, respectively), with the addition of 1% in mass of fibers. The fibers had been previously cut in the length of 15mm e 25mm and manually added to the mix. The correlations of the composites were obtained by bending tests in three points, following the RILEM 49 norm. The micro-structural characteristics were evaluated with electron microscopy. The results show that the insertion of fibers in the cementitious matrix reduces the maximum force applied to the specimen, even tough there was an increase in the material toughness and pseudo-ductility after the appearance of the first fissure. The longest fibers demonstrated better performance with a small highlight on the mauve fibers.