Papers by Keyword: Volume Fraction

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Authors: Xiao Lei Li, Xiao Jing Li, Jian Wei Zhang, Yan Hui Qie, Xin Ye Li, Bo Liu
Abstract: . The volume fraction of inclusions is one of the most critical parameters of polymer composites, which affects or even decides the mechanical behaviour of the materials. A procedure to calculate the volume fractions of inclusions of any size and shape distributions in polymer composites is introduced. It combines the capabilities of a digital processing technique to obtain configuration parameters of inclusions and of a statistical analysis which determines their volume fractions.The measurement principles and the basic procedures of the method are explained in detail. The procedure has been validated on simple shapes. The subsequent analysis is carried out using the method and is shown to be stable in some cases.
283
Authors: Ke Zheng Sang, Chun Feng Wan
Abstract: SiC/Al composites with high volume fraction of SiC were prepared at 1150°C by pressureless infiltration. The volume fraction of SiC was increased by decreasing the amount of starch in the green body. Both the microstructure and the strength of the composites were investigated. The results showed that the strength decreased with the increasing of the particle size and volume fraction of SiC. It was suggested that the interface between the SiC particles, which were not sintered, make of the defects in the composites. The defects led to the decreasing of the strength with increasing of the volume fraction of SiC.
189
Authors: Yu Hong Zhao, Hua Hou, Yu Hui Zhao
Abstract: The microscopic phase field approach was applied for modeling the early precipitation process of Ni75AlxV25-x alloy. Without any a prior assumption, this model can be used to simulate the temporal evolution of arbitrary morphologies and microstructures on atomic scale. Through the simulated atomic pictures, calculated order parameters and volume fraction of the θ (Ni3V) and γ′ (Ni3Al) ordered phases, Ni75AlxV25-x alloys with Al composition of 0.05, 0.053 and 0.055 (atom fraction) were studied. Results show: For these alloys, θ and γ′ precipitated at the same time. With the increase of Al content, the amount of γ′ phase is increasing and that of θ phase is decreasing; the precipitation characteristic of γ′ phase transforms from Non-Classical Nucleation and Growth (NCNG) to Congruent Ordering + Spinodal Decomposition (CO+SD) gradually, otherwise, the precipitation characteristic of θ phase transforms from Congruent Ordering + Spinodal Decomposition (CO+SD) to Non-Classical Nucleation and Growth (NCNG) mechanism gradually. Both θ and γ′ has undergone the transition process of mixture precipitation mechanism with the characteristic of both NCNG and CO+SD mechanism. No incontinuous transition of precipitation mechanism has been found.
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Authors: E.G. Bennett, L.J.M.G. Dortmans, M. Hendrix, Roger Morrell, G. de With
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Authors: H.H. Ya, H. El-Sobky
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, Vf = 5% to 20% and average angle of orientation, θ = 50o to 80o to evaluate the effect of anisotropy and Vf on the energy absorption capacity and collapse modes. The observations indicate that, the samples containing of higher Vf and θ, collapsed in brittle failure mode (fragmentation), while those with less Vf and θ angle collapsed in non-axis-symmetric (diamond) mode with local fracture. The galss fillet with polypropylene-60o (GPP-60) displayed the highest specific energy absorption (Es) compared to the other GPE, MDPE and LDPE pipe samples. However, the glass fillet polyethylene – 75o (GPE-75) displayed the highest Es and the glass fillet polyethylene – 65o (GPE-65) displayed the lowest Es 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 15o (GE-15) / which is 30 kJ/kg, and much higher than aramid-epoxy-15o (AE-15)/ which is 9 kJ/kg.
141
Authors: Nor Azwadi Che Sidik, N.G. Yen Cheong, Alireza Fazeli
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.
539
Authors: Qing Xin Zhao, Jin Rui Zhang, Zhao Yang Liu, Ran Ran Zhao
Abstract: By means of the three-point bending impact equipment, with the measurement of ultrasonic velocity, the low velocity impact damage evolution of reactive powder concrete (RPC) with 0, 1%, 2% and 3% volume fraction of steel fiber were tested. In this study, the damage variable D pertaining to ultrasonic velocity had been selected to study the damage evolution process of RPC. The results indicate that the fatigue damage process of RPC is linear. The addition of fibers effectively improves the impact energy absorption behavior of RPC matrix, and the damage variable D of RPC with different fiber dosages increases by 1.1~3.5 times than that of plain concrete when it is ultimately destroyed.
252
Authors: A.W. Bowen, M.G. Ardakani, John F. Humphreys
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