Abstract: Composite material referred to build speed boats with a lightweight and also endured to support a crushing load. To design and analyze speed boats to support a collision accident, the composite material would be implemented into finite element model. This research had proposed the material model of a fiberglass composite material which used to construct speed boats in Pattaya, Thailand. The rectangular plate of composite material was analyzed according to the drop weight impact test. The orthotropic and isotropic material models were applied to define material properties of the finite element model of the fiberglass plate. The finite element analysis (FEA) results were compared with experimental data. The FEA with isotropic material for modeling the fiberglass material results were in good agreement with experiment. There was an average difference of 0.4195 J when compared the residual energy with the experimental data. Consequently, this fiberglass material model would be used to analyze the speed boat collision in a further work.
Abstract: Polyaniline and graphite composites at different graphite loading were synthesized via solution method by using N-Methyl pyrrolidone (NMP) as a solvent. The structural and electrical properties of the composites were analyzed by using XRD, FT-IR and four-point probe method. The increment in the graphite content improved the conductivity of polyaniline (PANI) from 0.017 to 0.050 S/cm. The improvement in conductivity were also being observed through peak shifted in XRD pattern and FT-IR spectra.
Abstract: Graphite has attracted both academia and researchers due to its outstanding properties such as having strength 200 times stronger than steel, great efficiency of heat and electricity conduction, low cost and also facile fabrication. In this study, two facile approaches of producing nanosize graphite were performed; thermal expansion and sonication. Graphite that was produced are used as reinforcement in epoxy composite for adhesive applications. In order to determine the mechanical properties of the composite, tensile test was performed using Dumbbell shape of sample. The outcome of the test shows that 1 wt% of expanded graphite produce the highest value of Young Modulus which is 18 MPa. It was also found that adding more expanded graphite increased the ductility of composite by lowering epoxy brittleness. As for adhesive testing, double cantilever beam was used using Universal Testing Machine where the result shows that 1 wt% of expanded graphite demonstrates the highest value of adhesive toughness which is 9398 J/m2. The result of porosity-density indicates that porosity of composites will affect the mechanical properties. From the overall results, it is conclude that smaller weight percentage of expanded graphite produces better composite while for sonication process shows no difference at all. Thus demonstrates that time of dispersion does not give significant effect on the maximum load and stress of the composites.
Abstract: In the present work, the development of flyash-based friction composites for replacing asbestos material was systematically proposed. In order to solve the high-testing cost and time consuming problem in design formulation process, the mechanical properties of composites were first investigated with regarding to the contents of phenolic resin, friction modifiers and aramid fibers. Friction performances were continually tested with the samples optimized mechanical properties. When considering the results of mechanical testing, it was observed that the elastic modulus and compressive strength decreased with increasing resin fractions in the corresponding test ranges. On the other hand, an addition of friction modifiers and fiber contents can be contributed the mechanical strength. In the friction performance results, an addition of 2.5 wt% fibers showed enhancing of friction coefficient and decreasing of wear resistance at elevated temperature ranges of 100 oC to 200°C. Conversely, the composite filled with 5.0 wt% aramid fiber presented the stability of friction efficient in ranges of 0.56-0.57 and also gave better wear resistance lower than 0.39×10-7 cm3/N.m.
Abstract: This paper introduces the developing background of spherical non-metallic explosion suppression materials, and the cook-off experiment of imitated tank filling materials by self-made cook-off devices. During the experiment process, explosion doesn’t occur in imitated oil tanks and pipelines, and the perfectness ratio of spherical non-metallic explosion suppression materials is up to 96% after the experiment, which shows spherical non-metallic explosion suppression materials have good flame retardant and explosion suppression performance. On this basis, finally, the explosion suppression mechanism of spherical materials is analyzed and the application prospect of this material is looked.
Abstract: Deposition of NiCr-CrC(20NiCr) metal matrix composite (MMCs) coating have been applied on the substrate of boiler tubes material with High Velocity Oxygen Fuel (HVOF) thermal spray method and constant parameter. Variation of particle size and composition on MMCs was conducted to determined the optimum conditions for boiler applications. Microvickers hardness, metallography and thermal shock resistance testing were investigated. The best performance for boiler tubes application is MMC NiCr-CrC(20NiCr) with 270 mesh of NiCr particles size and 60:40 of composition as evidence by the highest of hardness value (410 Hv) and slightly of discoloration after thermal shock resistance with two variation cooling medium. While at MMC NiCr-CrC(20NiCr) with 70:30 variation composition, coating hardness value will decrease in line with the smaller of particle size of NiCr.
Abstract: Understanding the failure behaviour of composite laminate is crucial in designing a reliable composite structure. Failure analyses have been carried out widely. Nevertheless, the composite laminate displacements before the occurrence of failure have not been analysed thoroughly, especially when comparing between Glass/Epoxy and Graphite/Epoxy, which are the two most common composite laminates. For example, it could be observed that the lamination schemes and variations of angle orientation could affect the displacements and failure behaviour of the symmetric laminate. Therefore, this paper aims to investigate the effect of lamination scheme and angle variations to the displacements and failure behaviour of two most common composite laminates, which are Glass/Epoxy and Graphite/Epoxy laminates. Finite element modelling and analysis of symmetric Glass/Epoxy and Graphite/Epoxy laminates with various angles of fibre orientation subjected to uniaxial tension are performed. Maximum Stress Theory and Tsai-Wu Failure Criteria are employed to determine the failure load. Prior to that, convergence analysis and numerical validation are carried out. Displacements and failure behaviour of the Glass/Epoxy and Graphite/Epoxy laminates (symmetric) are analysed. The failure curves (FPF and LPF) for both theories (Maximum Stress Theory and Tsai-Wu) are plotted and found to be very close to each other. Therefore, it can be concluded that the current study is useful and significant in enhancing knowledge about the failure behaviour, deformation behaviour and mode of failure of composite laminate.
Abstract: This research studied foaming of natural rubber (NR), epoxidized natural rubber (ENR) and ethylene vinyl acetate copolymer (EVA) blends vulcanizate. The contents of NR/ENR/EVA investigated were 60/10/30, 70/10/20, 50/20/30 and 60/20/20 to keep NR based to 70 and 80 % by weight whereas EVA contents were 20 and 30 % by weight. ENR used in this research was ENR 50. The content of ENR was varied as 10 and 20 % by weight with restpect to total polymer content. The Efficient vulcanization and peroxide systems were used for rubber vulcanization in order to cure both rubber and EVA. Oxydibenzenesulfonyl hydrazide (EW or OBSH) was used as foaming agent. The results showed that rubber blends with 20% ENR tended to show better compatibilization between NR and EVA. The viscosity of rubber blend which indicated by minumum torque was increased with the content of ENR. Cell size of rubber blends foam containing ENR 20 % showed rather normal distribution than ENR 10%. Foam with high content of NR based rubber showed slightly higher density than the other systems. Tensile properties of rubber blends foam were dependent upon NR based contents and compatibility between NR and EVA. Rubber blends foam with high ENR content showed higher specific secant modulus. The specific tensile strength and elongation at break were slightly inferior. The specific tear resistance of the rubber foam was independent on compatibility. High EVA content reduced both specific compressive modulus and compressive strength of the foam. For the foam that contained EVA domain showed permanent deformation and hence high in compression set. Compatibilized rubber blend foams and the foam with high EVA possessed low ball rebound resilience.
Abstract: The purpose of this research is to optimise the processing condition of injection moulding towards samples made from polypropylene-nanoclay-bamboo fibre with compatibilizer. The defects that have been controlled upon the optimisation were shrinkage and warpage. The selection of injection moulding processing condition was packing pressure, melt temperature, screw speed and filling time. The research started by drying the bamboo fibres at 120°C. Then, the 1 wt. % fibres were mixed with 79 wt. % of polypropylene, 15 wt. % of compatibilizer and 5 wt. % of nanoclay. The mixing process was performed by using Brabender Plastograph machine. After that, pallets were produced by using Plastic Granulator machine for injection moulding process. The optimisation process was accomplished by adopting the Taguchi method. According to the results, the value of warpage defect between compounding for 1 wt. % fibre and without fibre content was not significant. However the optimum setting of 170°C melt temperature, 35% packing pressure, 30% screw speed and 2 seconds filling time can significantly reduce shrinkage. In conclusion, the optimum processing condition of polypropylene-nanoclay, fibre bamboo had been achieved, and the existence of fibre obviously giving a promising manufacturing opportunity to improve the quality of the injected moulding products.