Papers by Keyword: Volume Fraction

Abstract: By conducting the quasi-static compression and split Hopkinson pressure bar testing,the flow strain - stress curves under strain rate range of 0.0001-1000/s and temperature range of normal-400°C of different volume fraction SiC particles reinforced metal matrix composite SiCp/6063Al were obtained. The commonly used Johnson-Cook constitutive model in metal materials was applied in this research. And on the basis of it, the influence of volume fraction to flow stress was utilized to establish the equivalent and homogeneous constitutive model.

Abstract: Soft magnetic material FeCoV is sensitive to magnetic field and its cost is lower than giant magnetostriction materials (Terfenol-D et al.). In the present investigation Pb (Mg_1/3Nb_2/3)O₃-PbTiO₃ (PMN-PT) with different thickness and FeCoV laminate with 0.8mm thickness were assembled into layer structure to study the effect of the PMN-PT volume fraction on the magnetoelectric coefficient of PMN-PT/FeCoV laminate composites. The ME coefficients and voltages have been characterized in the longitudinally magnetized and transversely polarized mode. The measurement was conducted under a static magnetic field superimposed with an alternating magnetic field. The influences of the static and the alternating field strength were discussed. The peak ME coefficient was obtained at 430 Oe. With the volume fraction of PMN-PT increased, the ME coefficient decreased within the experiment fraction. It can be explained by the module of M.I.Bichurin. A linear relationship was observed between the magnetoelectric voltage and the alternating field strength under a static field of 400 Oe. The ME voltage decreased when the PMN-PT volume fraction increased in the experiment fraction.

Abstract: –The behaviour of extruded glass fibre reinforced thermoplastic pipe under axial crushing load was investigated experimentally. It was envisaged that the difference between the axial and hoop moduli and strengths as well as the volume fraction would influence the mode of collapses and energy absorption. The moduli could be varied using a new extrusion technology, which controls the fibre orientation pattern, hence, the mechanical properties. The ability to vary the moduli and the fibre volume fraction provide means of controlling the collapse mode in order to optimise specific energy absorption. Axial compression tests were performed on glass filled Polypropylene and Polyethylene composite pipes. The samples were chosen with a variety of fibre volume fraction, V_f = 5% to 20% and average angle of orientation, θ = 50^o to 80^o to evaluate the effect of anisotropy and V_f on the energy absorption capacity and collapse modes. The observations indicate that, the samples containing of higher V_f and θ, collapsed in brittle failure mode (fragmentation), while those with less V_f and θ angle collapsed in non-axis-symmetric (diamond) mode with local fracture. The galss fillet with polypropylene-60^o (GPP-60) displayed the highest specific energy absorption (E_s) compared to the other GPE, MDPE and LDPE pipe samples. However, the glass fillet polyethylene – 75^o (GPE-75) displayed the highest E_s and the glass fillet polyethylene – 65^o (GPE-65) displayed the lowest E_s compared with in the GPE pipes. The specific energy absorption of GPP-70 pipe (24 kJ/kg) and GPE-75 pipe (12 kJ/kg) is almost 50 % and 25% of the amount of specific energy absorption of aluminium tubes (60 kJ/kg), respectively. Moreover, it is close to the specific energy absorption of glass-epoxy 15^o (GE-15) / which is 30 kJ/kg, and much higher than aramid-epoxy-15^o (AE-15)/ which is 9 kJ/kg.

Abstract: Nanotechnology is a novel approach in thermal engineering science to enhance the overall thermal performance of compact heat exchangers by the homogeneous dispersion of solid nanoparticles of higher thermal conductivity in conventional base fluid like water, oil, ethylene glycol etc. The heat transfer rate is substantially intensified by the addition of nanosized solid particles which provide superior thermo-physical properties in comparison with base fluid. In the present study, a numerical simulation is performed to investigate the turbulent convective heat transfer characteristics of Al₂O₃-water nanofluid of volume fractions (1%, 3% and 5%) through a rough circular tube subjected to constant heat flux for a range of Reynolds number 10,000 to 30,000. The finite volume method is employed for solving the governing equations and k-ω SST turbulent model for single phase analysis is considered. At a Reynolds number of 25000, application of nanofluid combined with rough tube enhances the Nusselt number by 13.10%, 21.86% and 63.03% in case of relative roughness of the wall of 0.001, 0.005 and 0.01 respectively.

Abstract: It is reported actual volume fraction of the primary phase in alloys is larger than the equilibrium value. Larger volume fraction of the primary phase may cause shrinkage cavities and surface or internal cracks. Although control of the solidified structure is important for the quality of cast products, this problem has not been fully elucidated. Taking these results into account, this study has been carried out in order to comprehend the phenomenon of larger volume fraction of primary phase. The Sn-Pb alloy has been used as a test alloy to examine the relation between supercooling for nucleation and the volume fraction of primary phase. Actually, the volume fraction of the primary phase in Sn-Pb alloy is larger than that of the lever rule. It was also observed that the volume fraction of β-Sn decreases with decreasing the supercooling in the early stage of solidification. In the final stage of solidification, however, the effect of supercooling on volume fraction of primary phase is small. Futhermore, when the supercooling was low, the volume fraction of primary phase slowly increased.

Abstract: This research has been carried out in order to analyse the possibility of fiberglass woven roving used as an alternative material for the hull of of fishing boat. The standard used in this analyzing process was the Standard of Biro Klasifikasi Indonesia (BKI), especially to find how the forces applied to the boat. Once the forces were found, they would be applied to justify the possibility mentioned above. The justification process was done by theoretically analyzing the mechanical properties of some fiberglass woven roving composites using mathematical software. The composites have been made by varying the mixture volume fraction between 0% - 100% within 10% interval, fiber orientation angle between 0^o – 90^o within 5^o interval, and then the results which met the requirements according to BKI Standard would be justified by the results obtained from experimental analysis. Based on the experimental analysis results, it could be stated that the fiberglass woven roving with composition of 40% - 60% and fiber orientation angle 0^o can be used as an alternative material for the hull of fishing boat.

Abstract: Al.6061/Al₂O₃ metal matrix composites (MMCs) has been fabricated by stir casting. The MMCs were prepared by addition of Al₂O₃ particulates reinfoced with varios Mg content, 8, 10, 15 %wt Mg. Al.6061/Al₂O₃ composites with different Mg contents were successfully fabricated by stirring technique under optimum processing conditions. Effects of Mg content on microstructure and hardness were studied by Scanning Electron Microscopy (SEM)-EDX, SEM-Xray Map, XRD and Rockwell Hardness. The results indicate that Al₂O₃ particles disperse homogeneously in Al matrix and interfacial reaction between Al matrix and Al₂O₃ particles is effectively controlled. Distribution of Al₂O₃ reinforcement and interfacial bonding were improved by adding Mg. Additionally, the hardness of composites were remarkably improved with the Mg. The highest hardness of composites obtained in 15%wt Mg with a value of 55 HRB.

Abstract: Metal matrix composite materials are finding increased applications in many fields due to their excellent properties. Adding of one more constituent in the metal matrix make the composites hybrid. Machining of these composite materials are important and is different from the conventional materials. In the present investigation, hybrid metal matrix composites is machined by using Polycrystalline Diamond tool and the effect of volume fraction on surface roughness in turning is evaluated and presented in detail.

Abstract: The paper presents the vibration response investigation of glass fibre/epoxy composite plates of different volume fractions. The different in composition of glass fibre is expected to yield different response hence can be used to determine the properties of the material. The laminate samples were prepared by compressed moulding process at volume fractions of 35%, 40%, 45% and 50% with 5mm thickness. Vibration signals at different volume fractions were then measured and the natural frequencies and damping factor were obtained. Feature extraction algorithms with respect to time and frequency domain were developed by means of signal processing methods to classify the signals according to the property of the materials. That indicates the vibration signals obtained shows potential to be used as non-destructive means for detecting the laminates composition.

Abstract: Nanofluids are basically nanoparticles in base fluids. Nanofluids have unique features different from conventional solid-liquid mixtures in which nanosized particles of metals and non-metals are dispersed. Due to enhancement of mechanical properties, nanofluids are widely used in heat transfer industries. Two type of base fluids which are water and 50-50 mixture of Ethylene Glycol with water (EGW) are tested. Copper (Cu) and Alumina (Al2O3) nanoparticles with volume fraction or concentration of 0.5 percent and 5 percent are examined in this study. In the recent decades, car manufacturers are exploring nanotechnology and applying onto mass production car such as Hybrid car that symbolize green products. Nanofluids in car radiator will increase heat transfer of the engine, reducing radiator size hence reducing fuel consumption and higher efficiency. On the other hand, water based nanofluids have better heat transfer compared to EGW based nanofluids. Results also show higher concentration will have better heat transfer. Thermal conductivity of nanoparticles will directly affect the thermal conductivity of the nanofluids and it is proportional related.