جستجوی مقالات مرتبط با کلیدواژه "glass fiber" در نشریات گروه "مهندسی شیمی، نفت و پلیمر"

Hypothesis: Glass-reinforced composites are used in the production of passively cooled combustion chambers. To improve the performance of these composites as well as to decrease their costs, the use of micron sized silicon dioxide particles has been widely used. In this work, the possibility of producing glass phenolic composites with nanosized silica as an alternative to micron-scaled silicon dioxide was investigated. In order to disperse nanosilica in composites uniformly, a combination of sonication and high stirring was used. In all cases, the blends were prepared according to following procedure: the resin was weighed and diluted in methyl alcohol, and then the selected amount of nanosilica was added. The resultant mixture was sonicated and stirred for 1 h simultaneously. For preparation of glass fiber nanocopmpsites, a theoretical amount of chopped strands was weighed first and then the fibers were mixed with resin or the nanocomposites. Each produced paste was placed in a cylindrical shaped mold and then the mass was compression molded at a pressure of about 10 bar and cured at 180°C. The thermal resistance properties of the produced materials were studied using an oxy-acetylene torch. In depth temperature profiles taken through the thickness of the samples, ablation and loss of mass data of the post-test surfaces were used to evaluate the effects of nanosilica. Furthermore, to investigate the material post-test microstructure, a detailed morphological characterization was carried out using scanning electron microscopy. Findings: In comparison to neat glass/phenolic composite, the introduction of just 2, 4 and 6 wt% nanosilica particles embedded in the matrix improved the mass loss of nanocomposites about 12, 19 and 31%, respectively

The idea of combining low weight and good mechanical properties has led to efforts to develop a new light fiber/metal laminate (FML) in the last decade. FMLs are hybrid composites consisting of alternating thin layers of metal sheets and fiber-reinforced epoxy prepregs. In this study, the effect of fiber orientation on tensile properties of this material is investigated both analytically and experimentally. An analytical constitutive model based on classical lamination theory by using Kirchhoff-Love assumption, which incorporates the elastic-plastic behavior of the aluminium alloy was applied. Test results show that fiber sheet, with zero angle in laminates, improve the tensile strength. The composite layers with different fiber orientation change specimen's mode of fracture. Good agreement is obtained between the model predictions and experimental results.

During the last decades a new class of materials named fiber/metal laminates (FMLs) was introduced. It is a hybrid composite consisting of alternating thin layers of metal sheets and fiber-reinforced composite material. FMLs have both low weight and good mechanical properties. In this study, the impact behavior of this attractive material is investigated. The effect of fiber angle, stacking sequence and capacity of test apparatus were examined. In addition specimens have been prepared in two sizes according to two standards of ASTM D256-93a for plastics and then ASTM E23- 01 for metals. Test results show that suitable layering, using more aluminum layers and fiber sheets with zero angle in laminates improve the impact strength. The amount of energy absorption in heavy apparatus is higher than the light apparatus.