Evaluation of weather influence on mechanical and viscoelastic properties of polyetherimide/carbon fiber composites

In order to investigate how environmental degradation affects the mechanical and thermal performance of polyetherimide/carbon fiber laminates, in this work different weathering were conducted. Additionally, dynamic mechanical analysis, interlaminar shear strength tests and non-destructive inspections were performed on this composite before and after being submitted to hygrothermal, UV radiation and thermal shock weathering. According to our results, hygrothermally aged samples had their glass transition temperature and elastic and storage moduli reduced by plasticization effect. Photooxidation, due to UV radiation exposure, occurred only on the surface of the laminates. Thermal shock induced a reversible stress on the composite's interface region. The results revealed that the mechanical behavior can vary during weather exposure but since this variation is only subtle, this thermoplastic laminate can be considered for high-performance applications, such as aerospace. © The Author(s) 2013.

Efeito do condicionamento ambiental nas propriedades de cisalhamento e viscoelásticas de compósitos híbridos metal-fibra

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Avaliação dos parâmetros de soldagem para compósitos de PPS/fibras contínuas com aplicações aeronáuticas

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Caracterização de compositos de matrizes poliméricas reforçadas com fibra de sisal e de vidro

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

A influência do processo de cura nas propriedades do compósito estrutural carbono/epóxi fabricado via VARTM: processamento e caracterização

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Influência da matriz polimérica e dos métodos de extração de corpos de prova em compósitos de fibra de carbono

Pós-graduação em Engenharia Mecânica - FEB

Avaliação do efeito higrotérmico nas propriedades mecânicas de compósitos de PPS/fibras contínuas

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Estudo das intempéries nas propriedades mecânicas e viscoelásticas de compósitos PPS/Fibras de carbono e EPOXI/Fibras de carbono de uso aeronaútico

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Obtenção e caracterização de compósitos de fibras de carbono/PEKK com aplicações aeronaúticas

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Environmental effects on viscoelastic behavior of carbon fiber/PEKK thermoplastic composites

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Effect of fiber orientation on the shear behavior of glass fiber/epoxy composites

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Exact Solution of the Elastica with Transverse Shear Effects

A new derivation of Euler's Elastica with transverse shear effects included is presented. The elastic potential energy of bending and transverse shear is set up. The work of the axial compression force is determined. The equation of equilibrium is derived using the variation of the total potential. Using substitution of variables an exact solution is derived. The equation is transcendental and does not have a closed form solution. It is evaluated in a dimensionless form by using a numerical procedure. Finally, numerical examples of laminates made of composite material (fiber reinforced) and sandwich panels are provided.

Aspectos petrográficos dos carbonatos da Formação Riachuelo - Albiano, bacia de Sergipe

The carbonatic rocks have great importance in petroleum geology, since most hydrocarbons reservoirs in the world are associated to this kind of rock. The new giant petroleum fields discovered in the Brazilian southeast Atlantic margin are directly connected to calcareous rocks, which are subjacent to the Aptian evaporite pack. This demand an increase in the number of geologists able to study such deposits. The Aptian carbonatic platform is completely exposed only in the Sergipe-Alagoas Basin. Therefore, it works as a natural laboratory to the study and understanding of this kind of rock. The Sergipe Basin is situated in the east Brazilian coast, and has its evolutional history is intimately related to the formation of the South Atlantic Ocean, through the break-up of the Gondwana supercontinent. The marine sequence of the Brazilian marginal basins is of Albian age and is marked by the development of carbonatic platforms. In doing so, this paper aims to analyze the Albian limestones from Riachuelo Formation of the Sergipe Basin. The project gave to the student the opportunity to increase his knowledge in carbonates, due to the laboratory and outdoor activities. The studied deposits, within a regional outline, were petrografically described, allowing interpretations about the evolution of the former South Atlantic Ocean. Ten points were visited where samples were collected for making of thin sheets. In this work several carbonatic facies were identified totaling 116 laminates described.

Caracterização de compósitos produzidos por VARTM para aplicações aeronáuticas

In recent years the aeronautic industries has increased investment in areas of technological research aiming at materials that offer better performance, safety, weight reduction and fuel consumption. For this reason the most studied materials are polymeric materials, due to their higher mechanical strength and higher stiffness. This work evaluated characteristics of two composite laminates produced from the same process, but they differed only in regions where the resin was injected and the vacuum position. The composite laminates were SC-79 resin reinforced with glass fiber fabric (plain weave) processed via VARTM. For this reason the material was subjected to mechanical tests such as: tensile, and fatigue following standards ASTM D 3039 and ASTM D 3479, respectively. The latter was observed the S-N curve. It was performed the ultrassonic C-scan analysis to check impregnation of the fiber. Considering that the process was the same for the two laminates, with small variations in the injection and in vacum ports, it was expected to find similar characteristics

Avaliação do efeito ambiental nas propriedades mecânicas e viscoelásticas de compósitos híbridos de titânio/fibra de carbono/resina epóxi

Hybrid composites combining metal plates and laminates with continuous fiber reinforced polymer, called fiber-metal (CHMF), have been particularly attractive for aerospace applications, due mainly to their high mechanical strength and stiffness associated with low density. These laminates (CHMF) consist of a sandwich structure consisting of layers of polymer composites and metal plates, stacked alternately. This setting allows you to combine the best mechanical performance of polymer composites reinforced with long fibers, to the high toughness of metals. Environmental effects should always be considered in the design of structural components, because these materials in applications are submitted to the effects of moisture in the atmosphere, the large cyclical variations of temperature around 82 ° C to -56 ° C, and high effort mechanical. The specimens of fibermetal composite were prepared at EMBRAER with titanium plates and laminates of carbon fiber/epoxy resin. This study aims to evaluate the effect of different environmental conditions (water immersion, hygrothermal chamber and thermal shock) of laminate hybrid titanium/carbon fiber/epoxy resin. The effects of conditioning were evaluated by interlaminar shear tests - ILSS, tensile, and vibration free