Avaliação de momentos fletores em estruturas de fundação tipo radier em concreto armado

It aims the comparison of these moments between an analytical plates theory and a computational numerical simulation. It is accented the details of studies about analytical theory as well the process, step by step, of a program that has as an influence the method of finite elements. The theory of plates has an extremely importance when it is talked about slabs and it takes as a base some fundamental hypotheses (that the middle point of the plate is considered flat and under formable) the points that are normal in relation to the middle surface is not considered because of its intensity that is irrelevant in comparison to the rest. The computational programs offer good results when they are applied in a correct way and, it resolves numerous functions in a short period of time. The objective is to highlight the importance of bending moments, its points of maximum and minimum, that has the objective of realize a good reinforcement sizing for a reinforced concrete. Furthermore, it can propitiate an economy in places that is demanded a small quantity of steel, before dimensioned for a load that is distributed in all the surface of the plate, at the same intensity

Projeto mecânico do sistema de transmissão de um veículo Baja

This study aims to determine the best configuration for the new gearbox of the new Baja´s vehicle from Piratas do Vale team, focusing on the gear train, in order to achieve high performance of it. To this end, first some information about the vehicle is gathered to determine the best pair of gears configuration, then calculations about maximum bending stress, fatigue and surface thereof are performed; ; thereafter static simulations are performed using an a appropriated software. Thus this paper shows a satisfactory design of the addressed, besides providing the Baja SAE team consultation material for future use in the project

Desempenho estrutural de vigas em madeira laminada colada armada

The objective of the present work was to evaluate Pinus’ glued laminated timber (glulam) beams and steel reinforced glulam beams, using PU mono-component adhesive in lamination step and epoxy adhesive to bond steel bars. The mechanical performance was verified through bending test, and the adopted method based on homogenized section, to considerate the differences between wood and steel mechanical properties. The homogenization section method proved itself effective in obtaining the stiffness of the parts in MLCA. The stiffness of reinforced beams increased 91% in comparison with glulam beams, differing only 5.5 % from value of stiffness calculated

Fractografia quantitativa e o conceito de tenacidade à fratura para a análise do efeitodo choque térmicos em TiO2

The present study evaluated the use of semicircular bending test (SCB) as an alternative to conventional bending test to examine the effect of thermal shock. Still, studies the behavior of fracture surfaces generated by monofractal behavior analysis, which allows us to evaluate the contributions of the microstructure and the mechanical context in forming reliefs during the crack propagation. The fractal analysis is made from elevation maps obtained by reconstruction method by extension of the focus stacks of digital images acquired in microscope. The specimens used were samples semicircular pressed TiO2 (rutile) with and without heat shock, prepared for testing mode I loading. Were also produced, specimens in the form of bars for Weibull statistical analysis. From the three-point bending test, we found the variation of fracture toughness between the samples after the heat shock and natural condition. The SCB test was feasible for the analysis of thermal shock resistance. The results showed that the value of the fracture toughness decreases as the heat shock treatment

Caracterização físico-mecânica de elementos estruturais roliços perfilados de Amaru

The study of physical and mechanical properties of wood is essential for its structural use and it is of great importance to the construction industry. Thus, this study aimed to determine the physical and mechanical properties of the wood Amaru - a hybrid of Eucalyptus, developed by Plantar Projects and Forest Products Ltda. In order to determine the properties of Amaru, round samples were used, which were provided to the Laboratory of Wood and Wooden Structures of the School of Engineering of São Carlos, University of São Paulo - LaMEM / EESC / USP. For the characterization of the physical properties, the apparent specific gravity and moisture content of the samples were determined. To the mechanical characterization, the following properties were evaluated: strength and stiffness in compression, strength and stiffness in bending, shear and tension. The procedures of the tests performed in this study were done according to the recommendations of the Brazilian Wood Standard ABNT NBR 7190:1997. The specimen used were confectioned in actual dimensions, according to as those used in the construction system proposed by Plantar. The results obtained from the tests performed showed that the mechanical properties approached the values proposed by the Wood Standard NBR 7190. The visual grading was important to provide a primary idea about the failure modes to be obtained from the tests performed. The bending test showed the modulus of elasticity (MOE) and Modulus of Rupture (MOR), which resulted in 15822 MPa and 101,7 MPa, respectively. The compression test resulted in values Ec0,m and fc0, 15698 MPa and 50,7 MPa. The tensile strength (ft0) of this hybrid was calculated and its value obtained was 60,8 MPa. The shear strength (fv0) was 8,2 MPa. The results obtained from the tests are the basis for engineers and architects to design structures using wood species Amaru

Análise de falhas por fadiga de alto ciclo em eixos de transmissão utilizando o método dos elementos finitos

This work presents a study that aims to validate the fatigue analyses developed on finite element commercial software, ANSYS Workbench. It was based on mechanical tests development of traction and hardness, to verify the mechanical properties of material that the shaft was manufactured (ABNT 1045 steel), it was developed bend test, with purpose to prove the confiability degree of computational analyses, obtaining the maximum stress in a work condition determined with 40 [kgf] of load applied, and at the end, was developed the fatigue test to obtain the number of cycles that the transmission shaft can support in a work condition with 8 [kgf] of load applied. The results obtained during the work present, have to be quite satisfactory with the theoretically expected

Reciclagem de poliestireno expandido: compósito com fibras de algodão para a confecção de placas de circuito impresso

In this work polymeric composites reinforced with cotton fibers, from the textile industry, were developed in order to manufacture printed circuit boards. It was used expanded polystyrene (EPS) as a thermoplastic matrix by melting it. For the obtention of 10% and 15% of fiber volume fraction in cotton fibers composites, it was used wasted cotton fibers as an incentive of recycling and reusing of the domestic and industrial wastes as well as for Expanded Polystyrene(EPS). The mechanical properties of the composites were evaluated by tensile and flexural strength from standardized test methods. Composites were characterized by a Scanning Electron Microscopy (SEM), Thermogravimetry (TG/DTG), Differential Scanning Calorimetry (DSC) and dielectric analysis. The analysis of the results showed that fiber in the composite directly influenced in the thermal and mechanical properties

Reciclagem de poliestireno expandido: compósito com fibras de sisal para confecção de placas de circuito impresso

In this work polystyrene composites reinforced with recycled sisal fibers were processed, in order to apply in the manufacture of printed circuit boards. A thermoplastic matrix of recycled polystyrene was used, this material came from waste expanded polystyrene (EPS) used in appliance's packages. Composites were prepared with 15% and 25% of sisal fibers. To obtain the composites, wasted EPS and natural sisal fibers were chosen, to encourage recycling and reuse of household waste and also the use of renewable resources. The composites were analyzed by standard tensile and flexural test, in order to verify the mechanical properties of the material. The characterization of the composite was done by scanning electron microscopy (SEM) , thermogravimetry (TGA / DTG) , differential scanning calorimetry (DSC) and dielectric analysis . The analysis of the results showed that the percentage of fibers in the composite influences directly the thermal and mechanical properties. Plates with a lower percentage of fibers showed superior properties at a higher percentage. The composite material obtained is easy to process and it's use is feasible for the confection of printed circuit boards, considering it's mechanical, thermal and insulative properties

Análise do desempenho físico-mecânico de painéis compensados de Pinus sp. produzidos com adesivos aquosos a base de poliacetato de vinila e de homopolímero vinílico

This study aimed to evaluate the physico-mechanical performance of three PVA adhesive formulations according to the Brazilian standards for plywood testing and to evaluate the results with those presented in the technical literature and specified in normative documents. The study presents the production process of the panels, the obtaining of samples and, finally, the implementation of physico-mechanical characterization tests based on plywood Brazilian standards. For the panels production it was used a gramature of 120 g / m² and applied a pressure of 15 bars and two temperature combinations and pressing time for each adhesive. The commercial adhesives used were PVA 1810, PVA 1060 and Vinyltec 239. The physical tests conducted were thickness swelling, density, moisture content and water absorption. The mechanical tests were static flexion, for the determination of elasticity modulus (MOE) and rupture modulus (MOR), and shear in the glue line. Among the three formulations studied none showed good performance in the presence of water. However, other trials in the adhesive showed better results and closer to the commercially equivalent used, in the case the urea-formaldehyde, was the PVA 1810, that can be applied in non-structural uses and in environments without the presence of moisture

Estudo de compósitos de madeira com reforço em bambu para utilização em mobiliário

Bamboo has been studied because of its peculiar mechanical properties and numerous possibilities of use, besides being a fast-growing grass and short cutting cycle. This study aimed to analyze the mechanical characteristics of wood-bamboo composite material, where the samples were developed from the combination of layers of bamboo as a structural reinforcement in solid pieces of pine and EGP panel parts. The species of wood used was Pinus taeda, and the bamboo species Guadua angustifolia and Dendrocalamus giganteus. All work was conducted at the Universidade Estadual Paulista - UNESP in the laboratory of Physical and Mechanical Properties of Wood. Tests including the density and tension parallel to grain of the bamboo species used and the static bending of composites in order to use this in the furniture industry. For the tests have been used as a basis the requirements of the normative document NBR 7190/97. The values obtained in the tests showed a significant increase in strength and stiffness compared to unreinforced parts, where there was an increase in MOE and MOR in static bending in all specimens used in evidence. The results showed the possibility of reducing sections in furniture components and the possibility of improving the mechanical properties of parts with defects found in wood of Pinus Itapeva region of São Paulo

Equilíbrio muscular e pico de torque após jogo de futsal

Indoor soccer is a modality of sport similar to football, which is accompanying an increasing of the number of participants. With the growth of this sport, increased as well the number of injuries, which has been requiring greater attention and care from the health professionals. AIMS: To investigate the functional balance before and after an indoor soccer game and analyze the maximum force before and after the game, in order to verify if there is a great loss of muscle strength of knee flexors and extensors during the game. METHODS: The study included seven amateur soccer players. The isokinetic evaluation was made using the Biodex 3 isokinetic dynamometer at velocities of 60°/s and 180°/s with five repetitions at each velocity for each leg. Further, the study analyzed the peak torque of each leg at each speed of the extensor muscles and flexor concentric and eccentric. RESULTS: Compared to the peak torque before and after the game, there were no significant differences. At 60°/s in the non-dominant leg, peak torque decreased after the game of the extensor concentric and eccentric. In the dominant leg there was a decrease of peak torque in eccentric flexion at 60°/s and concentric flexion to 180°/s. Comparing the peak torque between dominance, there was any significant differences in speed. However, in eccentric flexion at 60°/s before the match there was a significant difference. The peak torque of the dominant leg showed better results than the non-dominant leg. Regarding the functional balance there was no statistically significant differences between the muscles involved. CONCLUSION: From the results achieved, it is possible to conclude that the peak torque of flexor eccentric decreases depending on the length of the exercise. This muscle is stronger in the dominant leg, comparing to the non-dominant leg

Efeito do tratamento alcalino da fibra na resistência mecânica do compósito epóxi/capim-sapê

Due to growing concerns for reducing environmental damage caused by the use of non-renewable raw materials, there is a growing demand for research related to aggregate technology with environmental preservation. Thus, the use of non-renewable materials and less aggressive materials has been gaining attention. About composite materials, the exchange of synthetic fibers by natural fibers, especially vegetable fiber as reinforcement, has been increasing, due to its physical-chemical properties such as mechanical strength, nontoxic, low cost, low density, processing flexibility, non-abrasive to the process equipment, requiring simple surface treatments, etc. This objective was to process composites reinforced with long fibers of sapegrass in epoxy matrix and characterize the composites through mechanical tests. Three groups of composites were prepared according to the treatment received by the reinforcement: without treatment, alkali treatment at concentration of 5% w/v and alkali treatment at 10% w/v concentration. The materials were analyzed by tensile and flexural, and tests also optical microscopy and scanning electron microscopy (SEM). The results were statistically analyzed. As the main result, the alkali treatment of 5% in the sapegrass fibers increases the tensile and flexural strength, as a consequence of the improve adhesion between matrix and reinforcement

Comportamentos, térmico e mecânico, de compósitos de polipropileno e resíduo da hidrólise enzimática do bagaço de cana de açúcar

Pós-graduação em Engenharia Mecânica - FEG

Confecção e avaliação de chapas de madeira aglomerada com aproveitamento de resíduos de marcenaria industrial

Pós-graduação em Engenharia Civil - FEIS

Estudo da influência da adição de resíduos de óleo em concretos para aplicação em pavimentos

Pós-graduação em Engenharia Civil - FEIS