PPMEC PROGRAMA DE PÓS-GRADUAÇÃO EM ENGENHARIA MECÂNICA PRÓ-REITORIA DE PESQUISA E PÓS-GRADUAÇÃO Téléphone/Extension: (32) 3379-5923 http://www.ufsj.edu.br//ppmec
Dissertation/Thèse
2024
Thèses
1
  • MIKHAEL BRENER SOUSA RODARTE
  • STUDY OF CALCIUM PHOSPHATE COATING WITH SILVER NANOPARTICLE DEPOSITION ON ALUMIN SCAFFOLD.

  • Leader : ROSELI MARINS BALESTRA
  • MEMBRES DE LA BANQUE :
  • ARTUR MARIANO DE SOUSA MALAFAIA
  • MAGNA MARIA MONTEIRO SCHAERER
  • ROSELI MARINS BALESTRA
  • Sandra Maria Fernandes Carvalho
  • Data: 16 févr. 2024


  • Afficher le Résumé
  • In this work, porous alumina ceramics were produced by powder metallurgy process, using alumina as base material and ammonium bicarbonate (BA) as pore former. The CT 3000 SG alumina used has an average grain size of 0.8 µm. The BA powder has granulometry between 325 to 425 µm. The granulometric distribution of alumina was obtained by laser diffraction particle analyzer using suspension in isopropyl alcohol and compared with that obtained by analysis of micrographs by SEM (scanning electron microscopy). On the other hand, that of BA was obtained only through the analysis of micrographs in SEM. The concentration of BA used was 40% by mass. The alumina and BA powders were mixed in a planetary mill. The sample were compacted uniaxially with a pressure of 200 MPA. To remove the BA, a heat treatment was performed at 270°C for 120 minutes, with a heating rate of 0.5°C/min. Sintering was at 1500°C for 120 minutes. Porosity measurements were obtained using the Archimedes method. Consecutively, analyzes of distribution, interconnectivity and pore size were performed by analysis of micrographs performed by SEM. The sintering time and temperature were convenient for the consolidation of the ceramic. The 40% concentration of BA showed good results, with a porosity of 55% and macro and micropores well distributed, interconnected and with varied sizes. The BA was eliminated, as in the EDS results only alumina was identified in the material composition. The biomimetic coating process was carried out in order to promote a uniform layer of calcium phosphate across the surface of the samples, with the aim of making the samples bioactive, and consecutively promoting biological activity in them.

2
  • TIAGO AUGUSTO DE SALLES
  • A cooling system study in internal turning for an API serie steel. 

  • Leader : CARLOS HENRIQUE LAURO
  • MEMBRES DE LA BANQUE :
  • CARLOS HENRIQUE LAURO
  • ROBSON BRUNO DUTRA PEREIRA
  • LINCOLN CARDOSO BRANDAO
  • ETORY MADRILLES ARRUDA
  • JALON DE MORAIS VIEIRA
  • Data: 26 mars 2024


  • Afficher le Résumé
  • Currently, machining has been the process of metal-mechanical transformation of great importance and use, demanding several developments of technologies that aim at better efficiency of operations. As technology advances, consumers demand products with better cost/benefit, which in machining, impact on cutting tools with longer life, or in reducing operating costs such as the use of cutting fluids. However, in some cases, special needs outweigh these requirements, such as the presence of cutting oil in products from the oil/gas sector, making it important to search for techniques that can replace emulsions and increase tool life. In this sense, this work analyzed the use of the air-cooled system in the internal turning of a product from the oil and gas sector, compared with the use of emulsion and dry cutting. For this, the responses of forces in the cut, roughness and cylindricity in cutting conditions similar to those used in the industrial environment were evaluated. The results showed that, although the use of emulsion provides better responses, in some cases, there is improvement in the cutting forces with the replacement of the air cooled system. But, there was a worsening in the geometric deviation responses, roughness and cylindricity, due to the air flow.

2023
Thèses
1
  • Luan Carrera Santos
  • Tsts of biocide corrosion 

  • Leader : ALYSSON HELTON SANTOS BUENO
  • MEMBRES DE LA BANQUE :
  • GUILLERMO VILALTA ALONSO
  • LINCOLN CARDOSO BRANDAO
  • RHUAN COSTA SOUZA
  • Data: 3 mars 2023


  • Afficher le Résumé
  • .

2
  • Eustaquio Geraldo Alves
  • Evaluation of tensile strength of machined and formed threads into holes manufctured by friction 

  • Leader : LINCOLN CARDOSO BRANDAO
  • MEMBRES DE LA BANQUE :
  • CARLOS HENRIQUE LAURO
  • ETORY MADRILLES ARRUDA
  • LINCOLN CARDOSO BRANDAO
  • SANDRO PEREIRA DA SILVA
  • Data: 27 mars 2023


  • Afficher le Résumé
  • Threads are fastening elements of great importance in the assembly of mechanical components. The mechanical industry uses thread profiles and standardized diameters to assemble machines, parts of devices, and other equipment. Among the standard metric thread diameters, M6, M8, and M10 are the main ones, with the M8 diameter being the most used. Therefore, the objective of this work was to measure and compare the maximum tensile load supported by M6x1.00mm internal threads in an aluminum alloy AA 7075-T6, with 1, 3, and 5 threads fillets, manufactured by the  machining and forming processes. Screws with 12.9 grade were used to analyse the tensile strength of threads with a displacement speed of 1 mm/min and the dimensions of the specimens with an external diameter of 22 mm and thickness of 2.00 and 3.00 mm. After the tests and the necessary analyses, it can be observed that the machined threads presented more excellent resistance in aluminum AA 7075-T6. On the other hand, the threads manufactured by the conventional drilling process for opening machined and rolled threads showed the highest strengths in the tensile tests. In addition, it can be concluded that the screw used was able to withstand the stresses applied to the thread in AA 7075-T6 aluminum machined and laminated with 5 thread fillets. 

3
  • GABRIELA PAULA DA COSTA MOREIRA
  • Influence of shear stress on localized corrosion propagation in flow in rotating cage tests

  • Leader : ALYSSON HELTON SANTOS BUENO
  • MEMBRES DE LA BANQUE :
  • ALYSSON HELTON SANTOS BUENO
  • LUIZ ROBERTO MARTINS DE MIRANDA
  • RHUAN COSTA SOUZA
  • Data: 26 juil. 2023


  • Afficher le Résumé
  • EVALUATION OF LOCALIZED CORROSION AND FORMATION OF FeCO3 WITH THE PRESENCE OF FLOW IN DIFFERENT CONCETRATIONS OF SODIUM CHLORIDE

4
  • Otávio da Silva Andrade
  • DEVELOPMENT OF A PARTICULATE POLYMER COMPOSITE CONTAINING SILICON CARBIDE

  • Leader : TULIO HALLAK PANZERA
  • MEMBRES DE LA BANQUE :
  • TULIO HALLAK PANZERA
  • RODRIGO TEIXEIRA SANTOS FREIRE
  • MAIKSON LUIZ PASSAIA TONATTO
  • ANTONIO CLAUDIO KIELING
  • Data: 28 août 2023


  • Afficher le Résumé
  • This study evaluates the mechanical properties of polyester and polyurethane matrix composites based on castor oil, reinforced with different mass fractions (5% and 15%) of silicon carbide (SiC) grains with different sizes (37µm and 53µm) and shapes (sub-angular and angular) through a complete factorial analysis of 2¹4¹ order. 

5
  • PAULO VICTOR DE ASSIS
  • PHYSICAL AND MECHANICAL CHARACTERIZATION OF POLYMER COMPOSITES REINFORCED WITH JUTE CORDS

  • Leader : MARCIO EDUARDO SILVEIRA
  • MEMBRES DE LA BANQUE :
  • ANTÔNIO CARLOS ANCELOTTI JUNIOR
  • MARCIO EDUARDO SILVEIRA
  • RODRIGO TEIXEIRA SANTOS FREIRE
  • TULIO HALLAK PANZERA
  • Data: 21 sept. 2023


  • Afficher le Résumé
  • Composite materials can have excellent mechanical properties between the combination of materials and fiber orientation in order to produce optimized and specific structures for each application. When considering factors such as low cost, low density and the search for biodegradable materials, natural fibers and resins obtained from renewable sources has gained relevance in the production of composite structures. Thus, the present work aims to investigate, through a complete 22 factorial design, the effect of the matrix phase, epoxy resin or castor oil, and the reinforcement stage arrangement, unidirectional staple fibers or bidirectional fabric, on the physical and mechanical performance of polymer composites reinforced with jute staple fibers. The reinforcement phases jute staple fibers and bidirectional jute fabric were characterized by mechanical tensile test. The composite materials were characterized in tensile, bending, impact, apparent density, apparent porosity and water absorption tests. The mechanical behavior of composites reinforced with unidirectional staple fibers for three-point bending was investigated through numerical simulation with a nonlinear implicit and incremental formulation. The experimental study indicated that the use of castor oil as a matrix phase reduced the apparent density of the composites and increased the impact resistance. However, it also provided an increase in apparent porosity and water absorption, and reduced the flexural strength of the composites. The alteration of phase reinforcement in materials from bidirectional fabric to unidirectional staple fibers caused expressive increase in all mechanical properties. The averages of physical properties of apparent density, apparent porosity and water absorption were not statistically altered by changing the arrangement of cords. The composite made of epoxy resin and unidirectional staple jute fibers presented the best mechanical behavior in tensile and bending tests. Numerical simulations were well correlated with experimental tests for small displacements. The tensile modulus for the jute fiber obtained by numerical simulation was in line with the values found in the literature. The manufactured composite materials proved to be a sustainable and economical alternative for engineering applications, mainly those manufactured with unidirectional staple jute fibers, which exhibited satisfactory mechanical properties.

6
  • EDUARDO DILASCIO VIAL
  • Glass and aramid fibre-reinforced biobased polymer composites manufactured by vacuum infusion: a statistical
    approach to their mechanical properties

  • Leader : TULIO HALLAK PANZERA
  • MEMBRES DE LA BANQUE :
  • TULIO HALLAK PANZERA
  • GILBERTO GARCIA DEL PINO
  • JULIO CESAR DOS SANTOS
  • Data: 21 sept. 2023


  • Afficher le Résumé
  • This work compares the behaviour between epoxy and novel biobased castor oil matrix composites reinforced with glass and aramid fibres and manufactured by Resin Transfer Moulding (RTM) assisted by vacuum-infusion. A full factorial design (2² - DoE) is applied to statistically identify the effects of the factors, polymer and fibre type, on the tensile, flexural, and impact properties of these composites. The results follow a normal distribution and homogeneity of variances, validating the DoE. Both main factors affect tensile properties. Aramid fibre composites subjected to tensile loads improve by 76% their mechanical performance compared to the glass fibres case, while the epoxy matrix shows a superior behaviour (up to 39%) to the biobased castor oil polymer composites. The epoxy systems provide an increase of up to 46% of the flexural properties; in contrast, the type of fibre used is not statistically significant. The main factors and their interaction significantly affect the impact energy properties, and glass fibre-reinforced castor oil composites have 78% more impact resistance than the other combinations. Finally, the low bulk density of the castor oil polymer combined with aramid fibres however provides equivalent or superior specific performance to other composites that offer adequate absolute properties for secondary structural applications.

7
  • VANESSA GRACIANA FIAIA LIMA
  • An study of bushing forming in the friction drilling in commercial pure titanium fine sheet

  • Leader : CARLOS HENRIQUE LAURO
  • MEMBRES DE LA BANQUE :
  • CARLOS HENRIQUE LAURO
  • ETORY MADRILLES ARRUDA
  • LINCOLN CARDOSO BRANDAO
  • ROBSON BRUNO DUTRA PEREIRA
  • SANDRO PEREIRA DA SILVA
  • Data: 25 sept. 2023


  • Afficher le Résumé
  • The employing the principle to drilling holes in metal is a more recent development. Friction drilling, also known as flow drilling or friction drilling, is an unconventional manufacturing process in which a tapered-tipped carbide rotating tool is pressed into a material, usually metallic. With the contact between tool and part, there is an increase in temperature, and consequently, a decrease in the resistance to deformation of the material due to its flow, thus causing the hole to be made. In this process, there is no chip formation, what occurs is the formation of a bushing due to the flow of the material. The bushing can be used, for example, as a fixing point by brazing or be threaded, serving as a connection point for screw fixings. With different possibilities of applications, the possibility of performing the drilling procedure by friction in different materials is also highlighted, among them, the material studied here is commercially pure titanium, known to be a promising material in applications in the naval and aeronautical industries, and for being considered one of the best biocompatible metallic materials. In this context, this work evaluates the geometric deformations caused in the height of the bushing and diameter of the hole formed in the process of drilling by friction. For that, the rotation speed and the feed were compared, both in dry and lubricated conditions.

2022
Thèses
1
  • Carolina Aurélia Ribeiro Maestro
  • Corrosion behavior and biological responses of a double coating formed by thermal oxidation and biomimetic deposition of bismuth-doped CaP on the surface of Ti-6Al-4V alloy.

  • Leader : ALYSSON HELTON SANTOS BUENO
  • MEMBRES DE LA BANQUE :
  • FREDERICO OZANAN NEVES
  • JEFERSON APARECIDO MORETO
  • LEANDRO JOSE DA SILVA
  • Data: 31 janv. 2022


  • Afficher le Résumé
  • Infections associated with biomedical implants still exist and represent one of the main challenges involving these devices. Furthermore, in titanium alloy implants, corrosion problems can arise, due to the long-term and aggressive requirements of the body environment. Thermal oxidation can improve the mechanical properties of the surface as well as the corrosion response of titanium alloys. Biomimetic depositions of calcium phosphates (CaP), on the other hand, can improve their bioactivity. In addition, ion-doped CaP is used to promote specific characteristics, as in the case of bismuth, which has bactericidal action. Regarding biomedical implants, bacterial growth on the surface of the material is an important step in the development of an infection. This infectious process can lead to several problems, including the removal of the prosthesis. Considering the interests of the medical field, and that studies on CaP doped with bismuth are few and recent, this study aims to investigate the biomimetic deposition of a Bi CaP film on the thermally oxidized Ti 6Al 4V alloy. Coated samples were characterized morphologically and structurally using SEM/EDX, AFM, Raman spectroscopy, as well as XRD measurements. The EIE technique was used to understand the global electrochemical behavior in Hank's solution. The interfacial tension theory was used to determine the surface interaction free energy. Regarding the biological assays, cytotoxicity, biocompatibility, and inflammatory response tests were performed. The characterization results demonstrated the formation of a double coating containing rutile coated by DCPD and bismuth- doped hydroxyapatite. The EIE results showed that the thermal oxidation method associated with biomimetic deposition promoted an improvement in the corrosive properties of the Ti-6Al-4V alloy, suggesting that the double coating has great potential for biological applications. Finally, the double coating showed a more hydrophilic behavior, and the cytotoxicity, biocompatibility, and inflammatory responses showed that Bi-CaP reduced both Ti-6Al-4V alloy toxicity and its induction of inflammation, in addition to increasing levels of anti-inflammatory cytokines.

2
  • Filipe José Viana Ribeiro
  • SEQUENTIAL MULTISCALE MODELLING OF PARTICULATE AND CARBON FIBRE COMPOSITES CONTAINING SILICA.

  • Leader : TULIO HALLAK PANZERA
  • MEMBRES DE LA BANQUE :
  • MAIKSON LUIZ PASSAIA TONATTO
  • MARCIO EDUARDO SILVEIRA
  • TULIO HALLAK PANZERA
  • VOLNEI TITA
  • Data: 14 févr. 2022


  • Afficher le Résumé
  • Most composite materials are heterogeneous when observed microscopically. However, ordinary finite element analyses of composites do not consider the influence of phases on the mechanical behaviour of the material. This work evaluates different composites using a sequential multiscale methodology, which models each phase with a micromechanical computational analysis of the representative volume element (RVE) and brings the homogenised results to the macroscale. Three types of composites are made with epoxy matrix phase and are classified as silica particle-reinforced polymer (SPRP), carbon fibre-reinforced polymer, and carbon fibre silica particle- reinforced polymer or hybrid. RVE uses a 3D Finite Element (FE), and it is restricted with different boundary conditions. The macroscale represents the geometry of ASTM specimens fabricated for experimental testing with the FEM. A User Material subroutine (UMAT) reproduces the behaviour of micromechanical analyses at the higher scale. Experimental analysis characterise and validate numerical results. In particular, for the SPRP, the results were taken from literature. For fibrous composites, a hand layup method is performed considering the fibre volume fraction of 30%. In addition, the hybrid configuration considers 9wt% of the particles in relation to the total mass of the matrix. Tensile, compression, and in-plane shear tests are performed. Unidirectional laminates are characterised in the longitudinal (0º) and transverse (90º) directions for tensile and compression tests, while a 45º/-45º ply configuration is employed for the shear test. The results show good accuracy for elastic and inelastic responses when compared to experimental and numerical mechanical behaviours. This methodology can support future researches in the same field.

3
  • Letícia Maciel da Fonseca
  • NATURAL COMPOSITES REINFORCED WITH SHORT BANANA FIBRES

  • Leader : LEANDRO JOSE DA SILVA
  • MEMBRES DE LA BANQUE :
  • ANDRE LUIS CHRISTOFORO
  • LEANDRO JOSE DA SILVA
  • RODRIGO TEIXEIRA SANTOS FREIRE
  • Data: 13 juil. 2022


  • Afficher le Résumé
  • Natural fibres have some advantages over synthetic fibers, such as low density, high tenacity, biodegradability, reduced respiratory irritation, flexibility, and low cost, thus being a cellulosic fibre with satisfactory mechanical properties for use as reinforcement in polymeric materials. This work focuses on the use of banana fibres as reinforcing members, exploring the use of castor oil-derived polyurethane resin as a matrix phase. Among the parameters that can be controlled, are the length (10 mm and 30 mm), the grammage (0.0375 g/cm² and 0.0750 g/cm²) of the fibre; the fibre extraction process; and the alkaline treatment with sodium bicarbonate (NaHCO3). The potential use of this biodegradable composite was evaluated by its performance in mechanical tests of tensile and flexural strength. The analysis of the results (using DOE and ANOVA) considered the isolated parameters and the interaction between them in the physical and mechanical properties of the composite. It was observed that the fibre length, when considered alone in the first experimental analysis, impacts the flexural strength, even when considered in combination with the fibre weight. The composite reinforced by banana fibres showed much improved mechanical properties compared to the pure matrix, with the 30 mm fibre showing better behavior compared to the 10 mm fibre, and with a higher grammage. The fibre extraction process revealed composites with different mechanical properties, highlighting higher-weight composites with fibres from the first extraction process. Alkaline treatment, when combined with fibre weight, impacts the mechanical properties, generating less dense composites. Composites of greater weight and without alkaline treatment showed better results. Alkaline treatment on banana fibres was not effective. The composites manufactured with the first batch of fibres - larger size, and heavier weight - presented higher structural performance.

     

     

4
  • LUIZA FERNANDES SOARES
  • STATISTICAL PLANNING OF MIXING FOR BIODEGRADABLE FOAMFROM CASTOR

  • Leader : TULIO HALLAK PANZERA
  • MEMBRES DE LA BANQUE :
  • TULIO HALLAK PANZERA
  • RODRIGO TEIXEIRA SANTOS FREIRE
  • LEANDRO DE SOUZA LEAO
  • ANDRE LUIS CHRISTOFORO
  • Data: 4 août 2022


  • Afficher le Résumé
  • The search for materials with less environmental impact has driven mainly biodegradable and those derived from renewable sources. Biodegradable foams and resins derived from vegetable oils have been investigated and applied in different areas of engineering. Manufacturers stipulate the “ideal” ratio between polyol and prepolymer (a certain ratio taken as the best) associated with a range of applications. However, the various applications focus on the characterization of composites, that is, on the study of the proportions between the phases, but it does not provide purely characterization of the matrix phase. Knowledge about the physical and mechanical properties of matrices prepared with different proportions between polyol and prepolymer can help better understand the performance of the manufactured composite as well as the most appropriate indication of the proportions between the proportions of the adhesive for cases of requests and conditions in different application. This work describes the mechanical and physical properties of biodegradable castor-based foams composed of 2 polyols and 1 pre-polymer. Statistical planning design is used to identify the combined effect of polymeric components on mechanical and physical properties. Contour graphs are obtained, capable of describing the material properties according to the mass percentages of each component. The specimens are obtained through the reactive expansion of the constituents in only one direction, allowing them to obtain anisotropic properties. The results show that it is possible to obtain variations of up to 80% in the mechanical properties. The increase in P2 concentration leads to lower specific properties of the foam. P2 does not affect the final mechanical properties, but the foam density increases considerably. On the contrary, the P1 component increases the density along with the mechanical properties, while PP reduces the density and mechanical properties of the foams. Finally, mathematical models can optimise the mix of the components to achieve a particular performance. The transverse properties (perpendicular direction to the expansion) are higher than the longitudinal ones.

5
  • FILIPE AFONSO ASCENCAO
  • Evaluation of the influence of the manufacturing process on the numerical simulation of the impact of automotive crash boxes

  • Leader : MARCIO EDUARDO SILVEIRA
  • MEMBRES DE LA BANQUE :
  • BRUNO CESAR POCKSZEVNICKI
  • JETSON LEMOS FERREIRA
  • MARCIO EDUARDO SILVEIRA
  • MAURICIO CENTENO LOBÃO
  • Data: 31 août 2022


  • Afficher le Résumé
  • Crash-Test is a vehicle impact test that aims to analyze and evaluate a vehicle's ability to withstand different types of crash. During a collision, most of the impact energy is absorbed by the vehicle's structural elements in order to offer the greatest possible protection to the occupants. In addition to the test with the impact of the actual vehicle, simulation analysis using the Finite Element Method (FEM) is used. In this way, the FEM plays an important role in the analysis of the vehicle's impact resistance, reducing development time and project costs. Most of the structural components of the vehicle body are manufactured by the stamping process. This manufacturing process imposes a plastic deformation on the parts along with a distribution of non-uniform thickness, residual stresses, and strain hardening of the grains, especially in high strength and high ductility steels. 3D Scanners s are devices used to generate digital representations of real-world objects or environments. They can be used to evaluate possible geometry distortions arising from the manufacturing process. The 3D model of the component is obtained by measuring the distance from various points on the object's surface to a fixed point in space. In this study, the influence of the manufacturing process for three (03) different types of loading was analyzed: a quasi-static compression test at 5 mm/s of a crash box in order to calibrate the collapse load; a second test with a part of the main structure of the vehicle at 16 km/h and finally a test carried out in an isolated Origami crash box in an drop tower with 162 kg at a speed of 24 km/h. Then, the numerical simulation results will be compared with physical tests performed in the laboratory. The mapping of plastic strain and thickness variation had a significant influence on the correlation of the crash box collapse load as well as on the collapse mode in relation to the physical test. Scanning the crash box Origami after manufacturing showed a big difference in geometry when compared to original CAD and had a significant influence on the collapse mode correlation.

6
  • Rogério Teixeira Lopes
  • Investigation of mechanical properties of sustainable sandwich panels made of aluminium skins and arch-corrugated core

  • Leader : TULIO HALLAK PANZERA
  • MEMBRES DE LA BANQUE :
  • ANDRE LUIS CHRISTOFORO
  • JULIO CESAR DOS SANTOS
  • RODRIGO TEIXEIRA SANTOS FREIRE
  • TULIO HALLAK PANZERA
  • Data: 31 août 2022


  • Afficher le Résumé
  • The growing exploitation of natural resources and their unconscious use by man
    emphasizes a worldwide trend to develop sustainable and resistant materials, such as sandwich
    panels. Recycling and reusing products reduce the need for raw material extraction, conserving
    natural resources and eliminating environmental impacts. In addition, variations in core
    geometry and materials are investigated to improve the final mechanical properties. This work
    presents the development and characterisation of a sustainable sandwich panel of recycled
    aluminium skins bonded to an arch-shaped core obtained from reused aluminium cans. A full
    factorial design was performed to identify the effects of three factors: type of adhesive (two
    epoxies and one polyurethane), the average thickness of the adhesive (0.8 and 1.5 mm), and
    the orientation of core arches (aligned and alternated). The sandwich panels were tested under
    a three-point bending test, from which the main flexural properties were obtained. The
    properties were statistically verified using Analysis of Variance (ANOVA) and the Tukey test.
    The results showed the feasibility of the proposed sustainable structure, in which more
    satisfactory results of strength and stiffness were obtained for panels made with epoxy polymer
    type C (Epoxy RenLam-M + HY951), greater average adhesive thickness (1.5 mm), and
    alternate core orientation. The panels showed to be promising for secondary structural
    applications, having low weight, cost and presenting an alternative route for the reuse of
    components highly discarded in nature.

7
  • JOAO OCTAVIO ASSIS MARCAL
  • A study on the influence of cutting fluid temperature in the micro-cutting of commercially pure titanium

  • Leader : CARLOS HENRIQUE LAURO
  • MEMBRES DE LA BANQUE :
  • JOÃO PAULO DAVIM TAVARES DA SILVA
  • CARLOS HENRIQUE LAURO
  • ETORY MADRILLES ARRUDA
  • LINCOLN CARDOSO BRANDAO
  • ROBSON BRUNO DUTRA PEREIRA
  • Data: 13 sept. 2022


  • Afficher le Résumé
  • Sustainable machining methods have been developed to reduce or replace the fluids used in cutting metal in the industry. Several processes, such the minimum quantity lubrication (MQL) for example, have shown promising results in relation to the surface finish and the reduction of machining efforts, temperature, friction and tool wear. They also have high performance with high-speed cutting and when working with difficult-to-machine materials such as titanium and their alloys, characterized by its high strength, high melting point and low thermal conductivity, in addition to its wide application in several areas of engineering. Recent studies seek to improve its use also in the production of biomedical implants due to its low elastic modulus, corrosion resistance and its biocompatibility, without posing risks to human health. The finite element method together with the experimental tests allowed the evaluation of the influence of the fluid in different temperature conditions in relation to dry machining in the microcut process of commercially pure titanium specimens, Grade 2. The results pointed to the best dry machining performance. The temperatures adopted for the fluid did not present significant differences between them, or any characteristic that justified its use. The effects of the high pressure of the fluid injection pump were responsible for the increase in the friction coefficient, the machining forces and the specific cutting energy.

8
  • Filipe Augusto de Faria Cunha
  • Study of the behavior of Ni-based superalloys MAR-M247, during isothermal and cyclic oxidation at 1.000 and 1.100 °C, and MAR-M246, conventional and Nb-modified, during cyclic oxidation at 1.100 °C.

  • Leader : ARTUR MARIANO DE SOUSA MALAFAIA
  • MEMBRES DE LA BANQUE :
  • ARTUR MARIANO DE SOUSA MALAFAIA
  • FREDERICO AUGUSTO PIRES FERNANDES
  • KURT STRECKER
  • RENATO BALDAN
  • Data: 30 nov. 2022


  • Afficher le Résumé
  • Superalloys are mainly used because of their exceptional properties, such as mechanical strength and oxidation resistance. The oxidative process is commonly observed in engineering applications and it is usually accentuated under conditions involving high temperatures. These alloys are often used in operations involving high temperatures and stresses, such as gas turbines. This makes the study of oxidation for superalloys relevant. The main objective of this work was to study the oxidation process in the MAR-M247 superalloy, followed by a complementary analysis of the conventional MAR-M246 and Nb-modified MAR-M246 superalloys. MAR-M247 superalloy was exposed to isothermal tests at 1.000 and 1.100 °C for up to 300 hours. This alloy has also been tested cyclically at 1.000 °C for up to 200 cycles and at 1100 °C for up to 219 cycles. The superalloys MAR-M246 (Ta) and MAR-M246 (Nb) were evaluated in relation to cyclic oxidation at 1.100 °C, for up to 219 cycles, in order to study the influence of the replacement of Ta by Nb. The oxidation kinetics and the characterization of the oxidation products were evaluated. The characterization of the samples was performed by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD) and optical microscopy (OM). Some of the conclusions obtained in this work are: NiO, Al2O3, TiO2, Co3O4, NiCr2O4 e CoCr2O4 are common oxidation products for MAR-M247; the MAR-M247 alloy proved to be the most resistant to the oxidation process, followed by MAR-M246 and MAR-M246 (Nb), the last one exhibited the lowest resistance among the alloys.

9
  • FRANKLIN LEMOS DA COSTA
  • Cyclic and isothermal high temperature oxidation of ferritic stainless steel AISI 439.

  • Leader : ARTUR MARIANO DE SOUSA MALAFAIA
  • MEMBRES DE LA BANQUE :
  • ARTUR MARIANO DE SOUSA MALAFAIA
  • ROBSON BRUNO DUTRA PEREIRA
  • TARCISIO REIS DE OLIVEIRA
  • Data: 1 déc. 2022


  • Afficher le Résumé
  • High temperature oxidation processes occur in different types of machines and equipment in the most varied fields of activities, in which stainless steels are used. Therefore, it is important to study and characterize the oxide layers formed and the mass variations that occur during the oxidation of these materials. Ferritic matrix stainless steels appear as a lower cost alternative to austenitic steels for high temperature applications. In this way, the present work will present an analysis of the isothermal and cyclic oxidation in high temperature of the ferritic stainless steel AISI 439. Studies have shown that the initial surface finish of the sample can have an important effect on the oxidation kinetics and on the adhesion of the oxide film. Therefore, in order to evaluate the effect of roughness on the behavior of the oxidation kinetics of this alloy, two different surface finishes were used. Half of the samples were sanded with silicon carbide sandpaper to #600 granulometry and the other half remained with a factory surface finish (laminate) on the faces. The isothermal and cyclic oxidation tests were carried out at temperatures of 750, 850 and 950 °C, in a time interval of up to 100 hours or cycles. The thermal cycles consisted of heating and holding for 1 hour at maximum temperature, followed by cooling for 10 minutes. The microstructure and chemical composition of the oxide layers formed were analyzed by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and X-ray Diffraction (XRD). The alloy showed parabolic oxidation kinetics at the three test temperatures for the two surface finishes evaluated, which indicates the presence of an oxide film with protective characteristics. However, the surface with greater roughness (laminate) showed less tendency to detachment. The oxides Cr2O3, TiO2 and MnCr2O4 were identified in the XRD analyzes for the two surface conditions evaluated.

10
  • Daniel Felipe Celestino Campos
  • Numerical study of the inflluence of geometric modifications on the distribution of shear stress in the rotating gage samples.

  • Leader : ALYSSON HELTON SANTOS BUENO
  • MEMBRES DE LA BANQUE :
  • ALYSSON HELTON SANTOS BUENO
  • GUILLERMO VILALTA ALONSO
  • JOSÉ ANTÔNIO DA CUNHA PONCIANO GOMES
  • LOURIVAL JORGE MENDES NETO
  • RAFAEL ROMAO DA SILVA MELO
  • Data: 9 déc. 2022


  • Afficher le Résumé
  • Internal corrosion is one of the main failure mechanisms in oil and gas (O&G) pipelines. In order to protect the integrity of the pipelines, several researchers are dedicated to reproducing in the laboratory the environments to which the pipelines in the O&G sector are constantly exposed. Currently, the rotating cage (GR) of the ASTM G170-06 standard is one of the most used methodologies for testing the vulnerability of materials in corrosive media or the efficiency of corrosion inhibitors under turbulent flow regimes. However, the GR is a very conservative methodology and there are several factors responsible for this conservatism, for example, the non-uniformity in the loss of mass in the specimens. The objective of the present study is to evaluate, through a computational study, changes in the geometric attributes of the GR of the ASTM G170-06 standard, in order to verify the possibility of obtaining a more uniform distribution of the shear stresses in the specimens.

2021
Thèses
1
  • JOÃO GABRIEL DA CRUZ PASSOS
  • Analysis of the isothermal and cyclic behavior of FeMnSiCrNi alloys and characterization of the subsurface ferritic layer.

  • Leader : ARTUR MARIANO DE SOUSA MALAFAIA
  • MEMBRES DE LA BANQUE :
  • ARTUR MARIANO DE SOUSA MALAFAIA
  • CARLOS ALBERTO DELLA ROVERE
  • MARCELO FALCÃO DE OLIVEIRA
  • Data: 25 févr. 2021


  • Afficher le Résumé
  • Iron-based austenitic FeMnSiCrNi alloys, with shape-memory properties, are potentially cheaper alternatives to conventional austenitic stainless steels. However, the high manganese content reduces their high-temperature oxidation resistance. Manganese has a high affinity with oxygen and, in high temperatures, reacts with it, forming the oxide layer, which depletes the metallic substrate and forms ferritic structure in the oxide/metal interface region. Previous studies have shown several effects of this ferritic layer in physical and chemical properties of FeMnSiCrNi alloys, but there is limited information regarding the characterization of this layer and the mechanisms by which it is formed. In the present study, the alloys Fe-13,67Mn-3,46Si-8,32Cr-3,04Ni (A) and Fe-13,04Mn-3,77Si-9,56Cr-3,55Ni (B) were studied via cyclic oxidation tests at 800 °C and isothermal oxidation tests in temperatures between 675 and 1000 °C. The oxidation behavior and subsurface ferritic layers were evaluated by mass change analysis, as well as X-Ray Diffraction (DRX), Scanning Electron Microscopy (SEM), optical microscopy and Energy-dispersive X-ray spectroscopy (EDS) techniques. Alloy A was less resistant to oxidation, except at 700 °C, temperature at which alloy B presented higher mass gain, associated with the stabilization of ferrite at the oxidation temperature. The relationship between mass gain and ferritic layer thickness was linear. A mechanism by which the ferritic layer forms during cooling was proposed via analysis of manganese concentration gradients. In cyclic tests, the ferritic layer was thinner and more depleted in manganese, due to the formation of ferrite between cycles, inducing a chemical effect that consumes part of the substrate. Isothermal tests with varying cooling rates (by oven, air or water) showed that ferrite is formed, at least partially, at the oxidation temperature. The exception is at 1000 °C, temperature at which ferrite seems to form Only upon cooling.

2
  • GABRIELA LUIZA COTA COURA
  • DEVELOPMENT AND CHARACTERIZATION OF POLYMERIC COMPOSITES REINFORCED WITH PAPAYA BAST FIBRES

  • Leader : RODRIGO TEIXEIRA SANTOS FREIRE
  • MEMBRES DE LA BANQUE :
  • GILBERTO GARCIA DEL PINO
  • LEANDRO JOSE DA SILVA
  • RODRIGO TEIXEIRA SANTOS FREIRE
  • TULIO HALLAK PANZERA
  • Data: 18 mars 2021


  • Afficher le Résumé
  • The growing demand for materials that promote sustainable development and the preservation of the environment make natural fibres stand out in the development of composite materials. In order to improve the properties of these materials, much research has focused on several natural fibres, manufacturing techniques and process parameters. This work investigates the mechanical performance of papaya fibre-reinforced polymeric composites based on epoxy and castor-oil biopolymer. Design of Experiment (DoE) and analysis of variance (ANOVA) techniques are used to analyse the influence of papaya fibre type (inner and intermediate), fibre morphology (without holes, with alternating or coincident holes, and randomly-oriented ground fibres) and fibre orientation (longitudinally or transversally oriented fibres relative to the load). Papaya fibres are also characterised. The specimens are manufactured by hand lay-up, followed by cold uniaxial compaction, and characterized by tensile, flexural and impact drop tower tests. For epoxy-papaya composites, longitudinally oriented provide superior mechanical properties relative to transversely oriented fibres. Composites with longitudinally oriented fibres, without holes, exhibit better mechanical properties. Randomly-oriented short fibres provide much lower reinforcing levels compared to the other morphologies. The Tukey’s test reveals that the morphologies, composites without holes and with alternating holes, are statistically equivalent for traction and flexion properties. In the drop tower test, in contrast, short random fibres provide greater energy absorption. The density of papaya fibres, among the lowest in the plant kingdom, varies according to the fibre layer.

3
  • CRISLAYNE GABRIELA ANDRETO
  • Study of alumina scaffold with a biomimetic calcium phosphate coating.

  • Leader : ROSELI MARINS BALESTRA
  • MEMBRES DE LA BANQUE :
  • ARTUR MARIANO DE SOUSA MALAFAIA
  • MAGNA MARIA MONTEIRO SCHAERER
  • MARCELO JOSE BONDIOLI
  • ROSELI MARINS BALESTRA
  • Data: 30 juin 2021


  • Afficher le Résumé
  • Alumina is an advanced ceramic used as a biomaterial due to properties such as biocompatibility, high compressive strength, good chemical inertia in the physiological environment, among other good characteristics. Scaffolds are structures with pores of various sizes, well distributed and interconnected, thus favoring the adhesion of cells and the growth of tissue inside the pores. The biomimetic method was used for coating alumina scaffolds with calcium phosphate in order to improve bioactivity. The method presents advantages to low cost, reproducibility and applicability to the complex surface and porous structures. The study objective was to manufacture the porous alumina samples coated with calcium phosphate by biomimetic method for use as bioceramic scaffolds. The dense alumina samples were uniaxially compacted under pressures of 50, 100, 150, 200 and 250 MPa and sintered at 1500°C for 120 minutes. The pressure was determined experimentally to produce the scaffolds. The porous alumina samples using ammonium bicarbonate (BA) as a pore forming agent were uniaxially compacted at a pressure of 200 MPa with 30 wt.%, 40 wt.% and 50 wt.% BA, heat treated at 270°C for 120 minutes for removal BA and sintered at 1500°C for 120 minutes. Then, it was possible to determinate that porosity of 55% was obtained with 40 wt.% BA. The scaffolds were compacted at 200 MPa with 40 wt.% BA and 60 wt.% alumina, heat treated at 270°C for 120 minutes and sintered at 1500°C for 120 minutes. The samples were biomimetic coated submerging in a Simplified Solution (SS) of calcium chloride dehydrate (CaCl2.2H2O) and sodium hydrogen phosphate dehydrate (Na2HPO4.2H2O) for periods of 14 and 21 days. Analysis of laser particle size distribution was realized, Scanning Electron Microscopy (SEM), density and porosity using geometric and Archimedean methods, Energy Dispersive Spectroscopy (EDS), X-Ray Diffraction (XRD), Fourier-transform infrared (FTIR). The scaffolds had a porosity of 55%, with good distribution, interconnection and varying pores sizes. Calcium phosphate formation was observed in the scaffolds on both surface and pores after 21 days on biomimetic coating. The samples presented promising results to be used as scaffold.

4
  • BRUNO DA SILVA PROCACI
  • Evaluation of electrical power, dimensional deviation, and surface roughness of AISI H13 steel in the tangential plane grinding process.

  • Leader : LINCOLN CARDOSO BRANDAO
  • MEMBRES DE LA BANQUE :
  • ARTUR MARIANO DE SOUSA MALAFAIA
  • LINCOLN CARDOSO BRANDAO
  • ROSEMAR BATISTA DA SILVA
  • SANDRO PEREIRA DA SILVA
  • Data: 2 juil. 2021


  • Afficher le Résumé
  • Studies to improve the understanding of machining processes are important for efficient production. The performance of these processes depends on several factors, operational parameters, and other variables. Among the various processes, grinding stands out for its versatility and high dimensional accuracy. Although widely used, it still has some shortcomings, as chip removal is more complex when compared to conventional machining processes with defined geometry tools. In this context, this work aimed to monitor the electrical power of the main motor of the machine, correlating with the dimensional deviation and surface roughness in Ra and Rz parameters of AISI H13 steel in the process of tangential plane grinding process. The input variables tested were working penetration at three levels (0.015; 0.03 and 0.05 mm) and workpiece speed at two levels (10 and 22 m/min). A vitrified aluminium oxide wheel in three conditions was used, being in worn condition, and dressed with two dressing overlap ratios (1 and 5) correlating the dressing parameters and the wheel topography. The results showed that the increase of the working penetration caused an increase in the power signals, the dimensional deviations, and the surface roughness for the three conditions of the grinding wheel. Increasing the workpiece speed also caused an increase in the power; however, regarding the dimensional deviation and surface roughness, the values obtained were lower. The worst results were presented for the conditions imposed on the wheel while worn. In contrast, when dressed, the same wheel had a substantial performance improvement. Higher electrical power values, lower-dimensional deviations, and lower surface roughness were observed significantly when increasing the dressing overlap ratio. The results showed that the electrical power signal was sensitive to variations of the input parameters analysed. Its relationship with possible dimensional deviations and surface roughness values may be able to analyse and diagnose distortions that affect the final quality of the ground parts.

5
  • Júlia Nascimento Pereira
  • Evaluation and comparison of resistance to cyclic and isothermal oxidation at 900, 950 and 1000 ºC of stainless steeels AISI 303, 304L and 310.

  • Leader : ARTUR MARIANO DE SOUSA MALAFAIA
  • MEMBRES DE LA BANQUE :
  • ARTUR MARIANO DE SOUSA MALAFAIA
  • FREDERICO AUGUSTO PIRES FERNANDES
  • ROSELI MARINS BALESTRA
  • Data: 5 juil. 2021


  • Afficher le Résumé
  • Austenitic stainless steels are widely used in applications where they are exposed to high temperatures. Therefore, these materials need to be resistant to oxidation under these conditions. Furthermore, the determination of the application limits of each material and the proper selection for each condition of use must be made with care to avoid degradation and loss. Thus, the aim of this study was to evaluate and compare the resistance to cyclic and isothermal oxidation of austenitic stainless steels AISI 303, 304L and 310 at 900, 950 and 1000 ºC. Specimens were cyclically oxidized for up to 100 cycles and isothermally oxidized for 100 hours. Each thermal cycle consisted of 60 minutes at the oxidation temperature and 10 minutes in which the samples were exposed to room temperature for cooling. The mass variation of the samples was evaluated by oxidation kinetics and COSP (Cyclic Oxidation Spalling Program) analysis. The morphology and composition of the oxide layer formed were analyzed by X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS). AISI 303 and 304L steels showed good resistance to oxidation only at 900 ºC, both in cyclic and isothermal tests. AISI 310 steels showed less mass variation under all conditions compared to other materials due to the formation of a protective oxide layer composed of Cr2O3, MnCr2O4 e SiO2. Thus, while AISI 303 and 304L steels showed detachment at 950 and 1000 ºC, AISI 310 steel showed little detachment only at 950 ºC. The higher content of chromium and nickel present in AISI 310 allowed a protective layer to be formed. Finally, unexpectedly, AISI 310 steel showed greater resistance to detachment during oxidation at 1000 ºC than at 900 and 950 ºC.

     

     

     

6
  • JOAO VITOR MENDONCA CASTRO
  • Development and characterization of metacaulim based geopolymers with added epoxy resin.

  • Leader : KURT STRECKER
  • MEMBRES DE LA BANQUE :
  • KURT STRECKER
  • ROSELI MARINS BALESTRA
  • SIMONE PEREIRA TAGUCHI BORGES
  • Data: 17 août 2021


  • Afficher le Résumé
  • Geopolymers are a materials class, conceived thru the aluminosilicate alkaline activation. Could be obtained by industrial residue calcination (fly ash, bottom ash, ground granulated blast furnace slag, etc.) or calcinated materials (metakaolin). Exhibiting low cost, great availability and good chemical and mechanical properties. Cheap, with good workability and environment friendly materials have been a necessity in the construction industries. with this in mind this work aims on the development of a new mortar (constituted by diffrents weigth proportions), with better workability, mechanical and structural properties thru epoxy resin incorporation in the metakaolin based geopolymer. Were investigated the effects of 0, 15, 20 and 25% resin addiction by weight in relation to the base polymer in mortar with sand in 0:1, 1:1, 2:1 and 3:1 weight proportions by the base geopolymer or with resin content, in the mechanical properties 28 days after production, with 60‰initial cure. A 24 estatistcal planning was used. Were analyzed also the structural modification of the precursor and base polymer thru MEV and EDS. Even with both being significative and with interaction between them, the most influent factor in the process was sand percentage. All investigated response variables, had their properties changed with the resin percentage increase to 15, 20 and 25%. So in this work a superior substitute to CPT was found.

7
  • AURELIO SILVA FERNANDES
  • Influence of punch geometry on the deep drawing of steel-PVC-steel sandwich material with lubricants from renewable sources.

  • Leader : FREDERICO OZANAN NEVES
  • MEMBRES DE LA BANQUE :
  • FREDERICO OZANAN NEVES
  • ROSELI MARINS BALESTRA
  • JALON DE MORAIS VIEIRA
  • Data: 29 oct. 2021


  • Afficher le Résumé
  •  

    Global competition encourages manufacturing companies to overcome technical and commercial challenges that provide competitive advantages and positively impact the sustainability of their processes. In this context, the mechanical forming processes appear as a viable alternative in terms of efficiency, compared to other transformation processes. The deep drawing process consists of mechanically forming a blank into a final format specified by the project. This blank is forced against a die by a punch that usually has the internal shape of the finished part. In this research, the influence of the punch geometry and the type of lubricant on deep drawing by the Swift test was evaluated. There are few researches related to the influence of punch geometry. As for lubrication, the possibility of replacing mineral oils with vegetable oils impacts sustainability criteria because they are biodegradable, are easy to dispose of and do not affect the health of professionals. Cups formed from a steel-PVC-steel sandwich material were stamped using punches without grooves and with grooves. The lubricants were Renoform mineral oil and linseed and castor oil of vegetable origin. The analyzed responses were the maximum stamping force and roughness in the Ra, Rz and Rt profiles. It was found that the type of punch had a greater influence on the maximum stamping force, with a reduction occurring when the punch with grooves was used. The reduction in the maximum stamping force results in greater energy efficiency, minimizes friction forces, reduces press load among other advantages. When analyzing roughness, only the type of lubricant exerted influence. The study showed the possibility of replacing mineral lubricant with vegetable oils in some cases.


     

     

8
  • TOMÁS BARBOSA DA COSTA
  • Optimization of helical milling to obtain holes in biocompatible titanium alloy.

  • Leader : ROBSON BRUNO DUTRA PEREIRA
  • MEMBRES DE LA BANQUE :
  • ROBSON BRUNO DUTRA PEREIRA
  • LINCOLN CARDOSO BRANDAO
  • CARLOS HENRIQUE LAURO
  • JOAO ROBERTO FERREIRA
  • Data: 8 déc. 2021


  • Afficher le Résumé
  • Biocompatible alloys are important for the biomedical industry as they offer alternatives in different treatments. The Ti-6Al-7Nb alloy has excellent mechanical properties and can be used in implants, which can be require holes. The helical milling, compared to drilling, is recommended because presenting low levels of cutting efforts, better finishing, lower temperatures in the cutting region, all this, as a consequence of the kinematics of the process. In this dissertation, the main objective was to study the process of helical milling to obtain holes in biocompatible titanium alloy. In this study, cental composite design was used, making it possible to obtain second-order regression models, which can be optimized, depending on the cutting parameters of helical milling, namely, cutting speed, axial feed per tooth and tangencial feed per tooth. Surface roughness responses were evaluated. Principal component analysis was used to allow the transformation of a set of original intercorrelated variables was enough to represent all the roughness responses. A second-order model for the transformed response was obtained. Finally, for optimization, the NSGA-II bi-objective evolutionaty optizimation method was used to determined a set of optimal Pareto solutions for the surface quality response and material removal rate (MRR). Therefore, according to the optimization, the best values to obtain the best surface quality parameters should be set at 𝑓𝑧𝑎 = 0,033 µm/tooth and 𝑓𝑧𝑡 = 3,65 µm/tooth. While for greater productivity the factors need to be defined at 𝑓𝑧𝑎 = 0,04 µm/tooth and 𝑓𝑧𝑡 = 2,99 µm/tooth. As analyzed the images of scanning eléctron microscopy (SEM) it was possible to conclude that the ploughing effect had na influence on the deterioration of the surface quality at low levels of feed.

2020
Thèses
1
  • ANA CLARA FALEIRO PETRUCELLI
  • Avaliação da resistência à corrosão na indústria química do revestimento com Nb2O5 aplicado por aspersão térmica.

  • Leader : ALYSSON HELTON SANTOS BUENO
  • MEMBRES DE LA BANQUE :
  • ROSELI MARINS BALESTRA
  • ARTUR MARIANO DE SOUSA MALAFAIA
  • ALYSSON HELTON SANTOS BUENO
  • LECINO CALDEIRA
  • Data: 3 févr. 2020


  • Afficher le Résumé
  • Avaliação da resistência à corrosão na indústria química do revestimento com Nb2O5 aplicado por aspersão térmica.

2
  • RODRIGO JOSÉ DA SILVA
  • Characterisation of the elastic parameters of sandwich panels with a core of non-negligible rigidity by bending test and modal analysis.


  • Leader : FABIANO BIANCHINI BATISTA
  • MEMBRES DE LA BANQUE :
  • FABIANO BIANCHINI BATISTA
  • TULIO HALLAK PANZERA
  • JULIO CESAR DOS SANTOS
  • ANDRE LUIS CHRISTOFORO
  • Data: 17 févr. 2020


  • Afficher le Résumé
  • The present work was based on the proposal of a new methodology (RJS Method), through the three-point bending test, for the identification of the flexural modulus and shear modulus of sandwich panels with a core of non-negligible rigidity. Sandwich panels were characterised under bending in different sizes of width and length, in order to validate the proposition that, in practice, the geometry of the test specimen directly influences on parameters elastics identification. The elastic properties obtained by the RJS Method were statistically compared to theoretical values. Furthermore, these same properties were used to determine the modal shapes and the natural frequencies simulated by the finite element method. Modal parameters obtained through experimental modal analysis were compared to those obtained by the numerical simulation; as well were used in the virtual field method (VFM), applied to identify the flexural rigidity of composite material plates. The flexural modulus obtained using the RJS Method is statistically coherent when compared to the theoretical flexural modulus and to that obtained by the VFM. Although the RJS Method for identification of the flexural modulus has been validated through modal analysis, the same was not possible for the core shear modulus test – because the mode shape associated with the shear is not ideal, for this purpose, in sandwich panels. Nevertheless, the core shear modulus obtained by the RJS Method is consistent with the expected for the type of material of the cores under study.

3
  • FRANCIS FARIA GOULART
  • Deposition of Calcium Phosphate Coating by Biomimetic Method in Micro and Macroporous Titanium-Niobium Alloy Processed by Powder Metallurg

  • Leader : ROSELI MARINS BALESTRA
  • MEMBRES DE LA BANQUE :
  • ALEXANDRE ANTUNES RIBEIRO
  • ARTUR MARIANO DE SOUSA MALAFAIA
  • DEBORA VIEIRA WAY
  • ERIKA LORENA FONSECA COSTA DE ALVARENGA
  • ROSELI MARINS BALESTRA
  • Data: 18 févr. 2020


  • Afficher le Résumé
  • Studies show that porous titanium alloys promote osteointegration at the implant-bone interface improving the mechanical stability. However, researches on bioactive coatings that induce the formation of new bone tissue on the surface of metal implants have been gaining prominence, being calcium phosphate (CaP) coatings of great potential. In this work, samples of Ti35Nb were produced by powder metallurgy and coated with calcium phosphate (CaP) by biomimetic method, for use in orthopedic or dental implants. High purity titanium and niobium powders were mixed and uniaxially compacted. For fabrication of macroporous samples, a pore former additive was added in the mixture (Ammonium Bicarbonate – AB). The sintering of samples was performed at 1300 ºC for 2 h in an ASTRO furnace under argon atmosphere. The samples underwent a chemicalthermal treatment for bioactivate the surface by means of the formation of a sodium titanate interlayer. Then, the samples were immersed in a simplified biomimetic solution with ionic CaP-forming composition, for periods of 14 and 21 days. The samples were characterized in terms of density and porosity, as well as chemical, physical and mechanical analyzes were performed by SEM / EDS, SEM / FEG, XRD, RAMAN, XPS, SEM / FIB, TEM, Profilometry and Ultra Microhardness. In general, the formation of micro and macroporous Ti-β alloys were observed. The deposited coatings were identified as biocompatible hydroxyapatite phase. According to the literature hydroxyapatite is the most desired phase for implants application because it presents chemical composition closer to the bone.

4
  • Lucas Braga Lopes Gato
  • --

  • Leader : TULIO HALLAK PANZERA
  • MEMBRES DE LA BANQUE :
  • JULIO CESAR DOS SANTOS
  • MAIKSON LUIZ PASSAIA TONATTO
  • MARCIO EDUARDO SILVEIRA
  • TULIO HALLAK PANZERA
  • Data: 4 mars 2020


  • Afficher le Résumé
  • Sandwich panels are structures widely used in different fields of engineering. These structures are made of high-strength skins attached to a low-density core. Its main features are: high energy absorption rate, high strength and flexural stiffness, and high performance when submitted to compressive loads, in addition to low weight. This work describes the development and characterization of sandwich panels made from disposed polypropylene (PP) bottle caps, used as a circular honeycomb, and glass fibre composite skins. Three-point bending test is performed to assess the composite structure using the following parameters: Maximum Load, Core Shear Stress, Skin Stress, Core Shear Modulus, Flexural Strength and Flexural Modulus – as well as, their respective specific properties (ratio between properties and their densities). A full factorial design (DoE) along with the Analysis of Variance (ANOVA) is carried out to identify the effects of the core packing system (cubic, hexagonal and orthotropic) and micro-silica inclusions (7.5 %wt) at the upper, lower and both composite skins. Finite element (FE) analysis is developed to investigate and predict the failure mechanisms of the sandwich structure. The experimental force vs displacement curves are compared with the numerical obtained in the FE analysis to ensure a good adjustment of the model to the experimental data. ANOVA reveals that the cubic and hexagonal packing system contributes to increase the mechanical properties compared to the orthotropic packing. The presence of silica in both skins leads to enhanced panel strength and stiffness when compared to the incorporation in the upper or lower skin and in pristine condition. Specific properties follow the same behaviour as absolute properties; the best configuration is obtained when hexagonal packing and silica micro-particles are added to both composite skins.

5
  • Thaís da Costa Dias
  •  

    Investigation of Sandwich Panels with Metallic Faces and Honeycomb Core of Interlocked PVC Pipes.


  • Leader : RODRIGO TEIXEIRA SANTOS FREIRE
  • MEMBRES DE LA BANQUE :
  • RODRIGO TEIXEIRA SANTOS FREIRE
  • TULIO HALLAK PANZERA
  • LEANDRO JOSE DA SILVA
  • MAIKSON LUIZ PASSAIA TONATTO
  • Data: 4 mai 2020


  • Afficher le Résumé
  • The use of composite materials has been growing in various industrial sectors. Sandwich panels are structural composites with high flexural rigidity and low weight, consisting of faces, core and adhesive. Honeycomb cores composed of circular or tubular cells have been shown to be superior to hexagonal cells in terms of energy absorption under deformation, flexural strength and structural rigidity. On the other hand, there is currently a great debate about the amount of solid waste generated by the population worldwide, mainly polymeric waste. In this context, the present work proposes the direct use of polyvinyl chloride (PVC) tubes for the manufacture of sandwich panels with ISO 1200 aluminum faces. It is investigated the effects of the outside diameter of the tube (20 and 32 mm), type of packing (cubic and orthotropic) and type of connection between tubes (with or without mechanical interlocking) on the physical and mechanical properties of panels subjected to three-point bending. The properties are evaluated statistically through Analysis of Variance (ANOVA). The panels with orthotropic packing, 32 mm tubes and without interlocking present a better mechanical performance in relation to other conditions. Interlocking is not an efficient strategy due to the large increase in the density of the structure. The viability of using PVC pipes to fabricate sandwich panels is shown in this study, being a sustainable and economical alternative use of these solid residues from civil construction.

6
  • THIAGO AMARO RODRIGUES
  • NUMERICAL AND EXPERIMENTAL EVALUATION OF FATIGUE IN FLAT BENDING OF SAE 1010 STEEL UNDER THE INFLUENCE OF DIFFERENT PARAMETERS IN THE PROCESS SINGLE POINT INCREMENTAL STAMPING.

  • Leader : MARCIO EDUARDO SILVEIRA
  • MEMBRES DE LA BANQUE :
  • LUCIO FLAVIO SANTOS PATRICIO
  • MARCIO EDUARDO SILVEIRA
  • ROBSON BRUNO DUTRA PEREIRA
  • Data: 30 juin 2020


  • Afficher le Résumé
  • This study aims to determine the best condition of incremental stamping of sheets by single point (association of parameters) that presents the highest resistance to fatigue for the test specimens. For this, a blank press and two punches of different diameters were designed and manufactured. Subsequently, 12 SAE 1010 steel sheets were stamped in a Sinitron CNC milling machine. The stamped steel sheets were submitted to a non-destructive ultrasound test, in order to verify if the sheets lost thickness after the stamping process, using a thickness gauge T – Gage IV Sonatest. The stamped plates will be taken to be cut the specimens. These specimens will be used to analyze the surface finish with the measurement of Roughness levels in each specimen and for tensile and fatigue tests. In conjunction with these actions, the new support for fixing the specimens of the fatigue machine was designed, in which the raw material is already in the acquisition phase. As a partial result, it was found that both the plate holder and the punches performed their functions correctly. The steel sheets were plastically deformed without breaking or structural failures. The values obtained by the Ultrasound test were statistically treated and were in line with the Sine Law for measuring sheet thickness.

7
  • LUCAS ALEXANDRE DE CARVALHO
  • Performance of vegetable oils with silica microparticles as lubricant in deep drawing of the sandwich composite

  • Leader : FREDERICO OZANAN NEVES
  • MEMBRES DE LA BANQUE :
  • FREDERICO OZANAN NEVES
  • LINCOLN CARDOSO BRANDAO
  • JALON DE MORAIS VIEIRA
  • Data: 22 juil. 2020


  • Afficher le Résumé
  • The lubrication is an important parameter for the success or failure of a deep drawing operation. The formulation of traditional lubricants uses mineral oils, which are harmful to the operator's health and difficult to discard. Recent studies have proved the lubricating potential of vegetable oils in deep drawing, and seek for solid additives that can complement the properties of these base oils. The deep drawing of a composite material is highly applicable for the metal industry, meeting the multifunctional needs that steels cannot satisfy. The current work presents an experimental study using vegetable oils with silica micro particles in the deep drawing process of a composite in a sandwich arrangement, formed by a SAE 1006 steel blank, an electrolytic copper blank and a thin PVC inner layer. For the lubrication, were chosen the castor, cotton and canola oils, two samples of silica of different particle sizes, and three different concentrations 1, 3 and 5%. As a final product of the deep drawing, a cup with an internal diameter of 22 mm and a height of 10 mm was shaped. The effect of the lubrication on the deep drawing process was evaluated by the maximum stamping force and the surface finish of the cup, by the roughness parameters Ra and Rz measured on the side and bottom of the cup. The studied composite showed consistency with other materials for stamping. The maximum force values corresponded to previous studies, influenced only by the different types of silica. The influence of the lubrication on the roughness was observed only on the side of the cup. The best surface finish was obtained with the silica of greater granulometry, and sub-angular geometry, using the oils of castor and cotton, and by the addition of silica in lower proportions.

8
  • SÉRGIO LUIZ MONI RIBEIRO FILHO
  • Hybrid fibrous-particulate composites: a statistical approach

  • Leader : TULIO HALLAK PANZERA
  • MEMBRES DE LA BANQUE :
  • CARLOS THOMAS GARCIA
  • LEANDRO JOSE DA SILVA
  • RODRIGO TEIXEIRA SANTOS FREIRE
  • TULIO HALLAK PANZERA
  • Data: 17 août 2020


  • Afficher le Résumé
  • A statitistical approach based on the full factorial design 2¹4¹6¹ (DoE) is applied to verify the interaction effect of the factors (levels), fibre stacking configuration (carbon-C5, glass-G5, C2G3, G3C2, GCGCG and CG3C), inclusion of particles (silica, cement and carbon microfibre-CMF) and matrix-fibre volume fraction (40/60 and 60/40) on the physical, modal and mechanical properties of the hybrid system. Hybrid fibrous- particulate composites are characterised under three-point bending and drop tower impact tests, along with physical properties such as apparent porosity, water absorption, bulk density, ultra pulse velocity and damping factor. The impact and flexural fractured surfaces are examined by optical and scanning electron microscopy (SEM). The results reveal a significant synergistic effect, in which hybrid composites exhibit an overall performance improvement of approximately 20% compared to glass and carbon composites. A greater dependence on the fibre layup-sequence is found for the bulk density, damping factor, flexural modulus and strength, while the matrix/fibre volume fraction is the most relevant factor affecting the apparent porosity, water absorption and pulse velocity of the hybrid composites, indicating a mutual dependence; the impact behaviour also reveals consistent layup-dependent trends. However, the particle type factor is the main factor that affects impact energy and resistance. Flexural strength and impact resistance are increased when silica microparticles are added. A larger amount of matrix phase ratio leads to a more efficient rheology in terms of fibre-particle interface. In glass/fibre composites, the carbon fibre layers placed symmetrically on both tensile and compressive sides (CG3C) enhance the material mechanical performance. Finally, the fibre-particle hybridisation is a promising configuration in terms of physical, modal and, mechanical behaviour, for structural engineering applications.

9
  • RODRIGO DE ANDRADE REIS
  • Study of the behavior of conventional and niobium-modified MAR- M246 superalloy cyclically oxidized at 900 and 1.000 ºC.

  • Leader : ARTUR MARIANO DE SOUSA MALAFAIA
  • MEMBRES DE LA BANQUE :
  • ALYSSON HELTON SANTOS BUENO
  • ARTUR MARIANO DE SOUSA MALAFAIA
  • RENATO BALDAN
  • ROSELI MARINS BALESTRA
  • Data: 26 août 2020


  • Afficher le Résumé
  • Reis, R. A., (2020). Study of the behavior of conventional and niobium-modified MAR- M246 superalloy cyclically oxidized at 900 and 1.000 ºC. Dissertation (Master Degree) – Universidade Federal de São João Del Rei, 2020.

    The oxidation process consists of the reaction of metal alloys with gaseous atmospheres forming an oxide layer on the material surface. At the industrial processes, there are a series of engineering components exposed to oxidation (among them those made with nickel- based superalloys) with temperature changes, different heating and cooling rates and different frequencies. It configures the cyclic oxidation process. Therefore, this research aims to carry out a comparative study of conventional MAR-M246 superalloys, and, also, the same alloy, with tantalum replaced by niobium, to evaluate the formation of oxidized layers in cyclic oxidation tests and characterize them. To test, it was used an oven with an automated system, with cycles of 1 hour of heating and maintenance at high temperature and 10 minutes of cooling in air. The samples were tested for 120, 180 and 240 thermal cycles at 900 ºC and for 24, 120 and 180 at 1,000 ºC. To characterize the oxidized layers, X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and Energy Dispersive X- Ray Spectroscopy (EDS) were performed. The tests results at 900 ºC showed mass gains very close to both alloys, with the superalloy MAR-M246 modified with niobium it was showed slightly higher mass gain. In tests at 1,000 ºC, sulfur contamination in the atmosphere was detected, which became the environment more degrading, causing failure of the stainless steel support. However, even so, the two alloys proved to be quite resistant, with greater stability for the alloy containing niobium. Protective oxides, Cr2O3 and Al2O3 were identified in all test conditions, as well as TiO2, NiO and Ni(Co)Cr2O4. Internal oxidation of Al2O3 was identified at both test temperatures, but in greater amounts in samples oxidized at 900 ºC and, at this temperature, the modified MAR-M246 superalloy appeared to have less internal oxidation. It was noticed that the two superalloys had a very similar behavior in terms of mass gain, along with the oxidized layers. This fact suggests an advantage of using niobium for applications with cyclic oxidation at a temperature of 900 ºC due to its lower density and cost. The advantage in the use of niobium could not be affirmed for the temperature of 1.000 ºC due to the sulfur contamination of the cyclic oxidation oven, however, suggested a good behavior for both alloys in sulphidizing environments.

2019
Thèses
1
  • JUSCELINO HENRIQUE BERTOLATO SILVA
  • Monitoring of the turning process by means of electrical and vibrational parameters


  • Leader : LINCOLN CARDOSO BRANDAO
  • MEMBRES DE LA BANQUE :
  • LINCOLN CARDOSO BRANDAO
  • PAULO CEZAR MONTEIRO LAMIM FILHO
  • ROBSON BRUNO DUTRA PEREIRA
  • SANDRO PEREIRA DA SILVA
  • Data: 20 déc. 2019


  • Afficher le Résumé
  • Monitoring of the turning process by means of electrical and vibrational parameters


2018
Thèses
1
  • RENATA DE OLIVEIRA NOGUEIRA
  • Analysis of the influence of lubrication with solid particles on the stamping of ABNT 1010 and 1020 steels.

  • Leader : FREDERICO OZANAN NEVES
  • MEMBRES DE LA BANQUE :
  • CLAUDIO PARREIRA LOPES
  • FREDERICO OZANAN NEVES
  • MAIKSON LUIZ PASSAIA TONATTO
  • Data: 23 nov. 2018


  • Afficher le Résumé
  • The forming process is must used by industries and consists of changing the shape and dimensions of the material through the application of external mechanical stresses. The main forming processes are rolling, drawing, extrusion, forging and sheet forming. The sheet forming process can be divided into stretching, bending, deep drawing and cutting. Stamping is widely used in the automotive and white-line industries. However, for the stamping to occur the use of lubricants is preponderant. On the other hand, the stamping process causes structural modifications and on the surface of the product, such as alteration of the roughness, the tightness of the wall and the presence of residual stresses. Although the stamping process is used in several sectors, the literature on lubrication of stamped products with solid particles and the influence of lubrication on the residual stress of the material is very scarce. In this work was analyzed the influence of the lubrication in the process of cold stamping of ABNT 1010 and 1020 steels in the generation of residual stress and the surface quality of a product. The blank were stamped without lubricant, mineral lubricant and vegetable lubricant with polyethylene terephthalate particles. Hardness and roughness tests were performed in the samples to verify surface finish and the insertion of residual stresses of compressive or tensile stresses were generated on the material. The results showed that the lubrication generated compression stresses on the stamped parts. The best lubrication relative to microhardness was found in linseed oil with PET particles between 150-300 μm. Regarding surface finish, the best lubricants were vegetable oils combined with PET particles smaller than 150 μm and cotton with particles between 300-600 μm. In addition, numerical simulation was performed by the Deform program to compare the residual stresses obtained in the simulation with the experimental results. The simulation results did not converge with the experimental method. It is assumed that this divergence is due to the use of the coefficient of friction formula in this work.

2017
Thèses
1
  • ROBINSON ANTONIO APARECIDO ALVES
  • Desenolvimento e caracterização de compósitos cerâmicos e cerâmico-poliméricos destinados à restauração de monumentos históricos fabricados em esteatito (pedra-sabão)

  • Leader : KURT STRECKER
  • MEMBRES DE LA BANQUE :
  • ALOIZIO GERALDO DE ARAUJO JUNIOR
  • KURT STRECKER
  • LEANDRO JOSE DA SILVA
  • Data: 23 juin 2017


  • Afficher le Résumé
  • Desenolvimento e caracterização de compósitos cerâmicos e cerâmico-poliméricos destinados à restauração de monumentos históricos fabricados em esteatito (pedra-sabão)

2012
Thèses
1
  • José Sebastião dos Reis Silva
  • COMPARAÇÃO DO DESEMPENHO DE FERRAMENTAS DE CERÂMICA NO FACEAMENTO DE FERRO FUNDIDO NODULAR NO ESTADO ENDURECIDO

  • Leader : DURVAL UCHOAS BRAGA
  • MEMBRES DE LA BANQUE :
  • DURVAL UCHOAS BRAGA
  • FREDERICO OZANAN NEVES
  • JALON DE MORAIS VIEIRA
  • Data: 2 mai 2012


  • Afficher le Résumé
  • COMPARAÇÃO DO DESEMPENHO DE FERRAMENTAS DE CERÂMICA NO FACEAMENTO DE FERRO FUNDIDO NODULAR NO ESTADO ENDURECIDO

SIGAA | NTInf - Núcleo de Tecnologia da Informação - | Copyright © 2006-2024 - UFSJ - sigaa04.ufsj.edu.br.sigaa04