Abstract: The present study aimed at obtaining torsional stiffness, bending stiffness and stiffness center position of full composite wing using thin wall structure mechanics theory. The influence of stringer layout on wing integer structure stiffness was furthermore investigated. It was found that wing section stiffness was influenced by stringer layout and dimension. The best spacing of stringer was within the range from 130 mm to 150 mm, at the same time, stringer stiffness had more change by the differences of its numbers. The study of this paper provided important support for structural design and aeroelastic analysis on composite wing.
Abstract: Epoxy resin (EP) composites including carbon black (CB) and graphite (G) were produced and investigate. The in-plane electrical conductivity of EP/CB/G composites was measured. Various weight percentages (wt.%) of CB as a secondary filler and G as a primary filler were added into the EP as a matrix. Dispersion of CB and G within matrix were conducted by an internal mixer (Haake Reomix). Mixture of EP/CB/G was poured into the steel mold, and produced through hot press machine. In-plane electrical conductivity of EP/CB/G composites in terms of variation of CB and G concentration were measured by the Jandel multi high four point probe. The highest in-plane electrical conductivity of the EP/CB/G composites obtained was 120 S/cm. This value exceeds the requirement of U.S Department of Energy (DOE) target for bipolar plate application (> 100 S/cm).
Abstract: This study focuses on the influence of surface treatment and fibre sizes on mechanical behavior, physical properties and morphology of rice husk fibre (RHF) reinforced polylactic-acid (PLA). Modified RHF was prepared by using 6w.t.% sodium hydroxide (NaOH) and distilled water. PLA composite reinforced with 25w.t.% volume fractions of modified RHF was mixed using the internal mixer and fabricated by the mini injection moulding. Tensile and flexural strength results showed that the PLA composite with 100, 200 and 500μm particles sizes of water treated fibre are much higher than those of alkaline treated. DSC measurement was performed and indicated that the Tg, Tm and ΔHm of PLA reduced after reinforcement with water treated and alkaline treated fibres. TGA results showed that the treatment reduced the thermal stability of the PLA. FESEM micrographs for flexural fractured surfaces of composites showed micro crack and pores due to brittle fracture of the PLA matrix adjacent to the fibre as a result of the brittle nature of the PLA resin.
Abstract: This paper presents the effect of moisture absorption towards thermal modulus evaluation of Arenga Pinnata fibre reinforced epoxy composite. The specimens are produced by hand lay-up method for practically with the ratio of combination of fibre with epoxy and hardener. The fibres were treated with sodium hydroxide (NaOH) prior the composites fabrication. Then, it were submerged in the water for moisture absorption and left for 8 days, 16 days and 30 days. The flexural modulus indicates there is reduction of elastic modulus values over the submerged period. Thermal analysis depicted by storage modulus curve showed the submerged specimens were not affected too much as compared to the control specimens. In fact, their performances were remaining the same across the temperature across from-10°C to 100°C. It is suggested from the experimental result that Arenga Pinnata fibres have a potential prospect as fibre reinforcement composites in many application.
Abstract: Wood fiber has long been known as fiber reinforcement for concrete . Because of the availability and low cost of production, natural fiber has been used in less developed countries where conventional building materials are very expensive. Fiber added to cement composite for increasing toughness, strength, impact resistance and resistance to fire.In this study, initially it is expected to develop an environmentally matrix binder for the composite by utilizing fly ash as the largest proportion of the matrix binder, silica fume and limestone.Fillers used in this study are differentiated into sawdust and wood shavel. Wood shavel filler were on two condition : treated in base liquid and untreated. The particle size of the sawdust used for the composite were those retained on ≠ 0.60 mm sieve size, while wood shavelgradation was used as received.Results of the flow test of fresh mortar for the entire design matrix either without or with filler are very low, that do not meet the flow specification standard. The limestone matrix using 35 % by volume has a low compressive strength , as it acts as a diluent in the mixture. The optimized volume proportion of matrix composites is 12 % (filler) : 47 % (binder) : 41 % (water). This composite has a dimensional stability, compressive strength of 211.6 kg/cm2 > minimum requirement of cement board ( 150 kg/cm2 ), while the flexural strength 73.3 Kg/cm2 < provision of cement board ( 90-150 Kg/cm2 ) .The density of the composite boards is 1.28 gr/cm3, and this can be considered high, but this also causes the composite board difficult to be cut and installed. Most of the test results on the composite board referring to JIS A 5908 do not fit the provision for the cement boards, although the difference is not too great. Therefore, during the production, compaction and curing or post-production treatment need to be considered.
Abstract: In this paper various thermal energy storage mechanisms are overviewed. Furthermore, the effectiveness of three insulating materials based on alkali activated and prepared with different expanded perlite filler contents was investigated. The results showed that the developed materials could be used to insulate a thermal energy storage facility, operating in the temperature range of 650-800 °C.
Abstract: The influences of surface treatment on kenaf fibre for rubber toughened polyester filled carbon black (CB) and kenaf hybrid composite were investigated, in consideration for applications such as automotive parts and integrated circuits (IC) encapsulations. Kenaf fibres were divided into treated and untreated fibres, where 6% of NaOH solution was used as the treatment solution. Unsaturated polyester was mixed with 3% liquid natural rubber (LNR) as toughening agent and 4% of CB, before hybridised with both treated and untreated kenaf that were varied from 5, 10, 15, 20 and 25% using mechanical stirrer and moulded by using hot compression technique. Flexural and impact testing were conducted and it was found that the hybridisation of CB and treated kenaf fibres composite showed improvement on flexural properties compared to non-hybrid CB filled composites although there are slight decrement on impact toughness. The optimum fibre loading for both treated and untreated kenaf were found at 25%.
Abstract: Palm oil industry produces huge amount of oil palm decanter cake (OPDC). Currently it is not yet commercialized however due to its characteristics, it can be used to produce oil palm decanter cake natural polymer composite (OPDC-NPC). NPC is a type of material made by combining natural fiber with polymer. Therefore the objective of this paper is to produce NPC from OPDC and then determine its mechanical and physical properties such as elasticity, stiffness, tensile strength and water absorption rate. The OPDC samples were collected from Felda Trolak Palm Oil Mill. Prior to NPC development, the oil was removed from OPDC using hexane soxhlet extraction method. OPDC-NPC was fabricated using molding method where the mixture of 95% polypropylene (PP) and 5% OPDC were mixed using twin-screw extruder. The results showed that OPDC-NPC has an elasticity of 2231 MPa, stiffness of 30 MPa, tensile strength of 32 MPa and water absorption rate of 0.16 % which was slightly better with the other types of fibers.
Abstract: Nafion/Silica hybrid membranes were prepared via in situ solgel method for redox flow battery (RFB) system. In this work, a novel Nafion/organically modified silicate hybrids nanocomposite membrane was prepared via in situ solgel reactions for mixtures of tetraethoxysilane (TEOS) and trimethoxyprohanthiol (TMSP). The primary properties of Nafion/Silica hybrids membrane were measured and compared with Nafion and Nafion/SiO2 hybrid membranes. Fourier transform infrared spectra (FT-IR) analysis of the hybrids membranes reveal that the silica and organic modified silica phase is well formed within hybrids membrane. The XRD results indicate thatthe Nafionhybrid membranes are not influenced by SiO2 nanoparticles.Nafion/Silica hybrid membrane shows nearly the same ion exchange capacity (IEC) and slightly greater of proton conductivity as pristine Nafion-117 membrane. The water uptake for Nafion/Organosilica hybrids membrane shows greatly reduced than a pristine Nafion 117, suggesting of low water cross over that is mostly faced in the RFB applications.