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Murat E Sozer - One of the best experts on this subject based on the ideXlab platform.
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variation of part thickness and Compaction Pressure in vacuum infusion process
Composites Science and Technology, 2009Co-Authors: Bekir Yenilmez, Murat Senan, Murat E SozerAbstract:Abstract In vacuum infusion (VI), it is difficult to manufacture a composite part with small dimensional tolerances, since the thickness of the part changes during resin injection. This change of thickness is due to the effect of varying Compaction Pressure on the upper mold part, a vacuum bag. In this study, random fabric layers with an embedded core distribution medium is used. The thickness of the composite part and resin Pressure are monitored using multiple dial gages and Pressure transducers; the results are compared with the model developed by Correia et al. [Correia NC, Robitaille F, Long AC, Rudd CD, Simacek P, Advani SG. Analysis of the vacuum infusion molding process: I. Analytical formulation. Composites Part A: Applied Science and Manufacturing 26, 2005. p. 1645–1656]. To use this model, two material characteristics databases are constructed based on the process parameters: (i) the thickness of a dry/wet fabric preform at different Compaction Pressures, and (ii) the permeability of the preform at different thicknesses. The dry-compacted preform under vacuum is further compacted due to fiber settling in wet form after resin reaches there; the part thickens afterwards as the resin Pressure increases locally. The realistic model solution can be achieved only if the Compaction characterization experiments are performed in such a way that the fabric is dry during loading, and wet during unloading, as in the actual resin infusion process. The model results can be used to design the process parameters such as vacuum Pressure and locations of injection and ventilation tubes so that the dimensional tolerances can be kept small.
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Compaction of e glass fabric preforms in the vacuum infusion process a characterization experiments
Composites Part A-applied Science and Manufacturing, 2009Co-Authors: Bekir Yenilmez, Murat E SozerAbstract:An experimental procedure was designed to realistically characterize the Compaction behavior of e-glass fabric preforms during initial application of vacuum and mold filling stages of Vacuum Infusion (VI). To mimic VI, the loading (Compaction) was done on a dry preform, and the unloading (deCompaction) was done after the preform was saturated with resin. When fabrics were wetted at constant full Compaction Pressure, a significant decrease in thickness was observed for the random fabric, but not for woven and biaxial fabrics. The rate of change of thickness, ∂h/∂t had different signs and order of magnitudes when various constant Compaction Pressures were applied during fiber relaxation stage. Thus, previous Compaction-mold filling models based on static relationship between thickness and Compaction Pressure do not appropriately simulate the Compaction physics of VI. Time-dependent database of this study is a useful and straightforward tool to model VI, as demonstrated in Part B of this study.
I Chicinas - One of the best experts on this subject based on the ideXlab platform.
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soft magnetic composite based on mechanically alloyed nanocrystalline ni3fe phase
Journal of Magnetism and Magnetic Materials, 2005Co-Authors: I Chicinas, O Geoffroy, O IsnardAbstract:Abstract A new soft magnetic material, based on nanocrystalline Ni3Fe powder with a crystalline mean size of 17 nm, obtained by mechanical alloying and annealing, has been produced. Composite materials were obtained by covering the Ni3Fe particles with a polymer binder, then compacted into toroidal shape and finally polymerized. The magnetic properties (initial and complex permeability, the frequency dependence of the permeability and losses in the range 1–50 kHz) and electrical resistivity were studied in correlation with the dielectric content and Compaction Pressure.
J A Stegemann - One of the best experts on this subject based on the ideXlab platform.
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biosolids and microalgae as alternative binders for biomass fuel briquetting
Fuel, 2017Co-Authors: Rukayya Ibrahim Muazu, J A StegemannAbstract:Abstract Binders can be employed to improve the particle adhesion, compressive strength, abrasion resistance and energy content of densified biomass, such as briquettes. They may also reduce the energy cost of producing such briquettes, by reducing the Compaction Pressure, conditioning temperature and the wear on production equipment. This study explored and compared the effects of three different binders, including starch, enhanced treated biosolids and microalgae, on density, durability, energy content and combustion characteristics of fuel briquettes produced from blends of rice husks, corn cobs and bagasse, in a multilevel factorial design experiment. Briquettes had relaxed unit densities of 1.9–3.3 times the loose biomass bulk density, and were stronger than briquettes from the individual materials, with an average unconfined compressive strength of 125 kPa. An unconfined compressive strength of 175 kPa was achieved for a 2:4:1 blend of rice husks, corn cobs and bagasse with the microalgae binder at a Compaction Pressure of 31 MPa. Statistical analysis of the results showed that the addition of biosolids and microalgae binders significantly improved briquette density, while the addition of starch reduced briquette density, and biosolids reduced briquette strength. Of all the briquettes produced with the three binders, those containing the microalgae binder were found to be most durable, with a higher energy value, slower mass loss during briquette combustion, and a higher afterglow time. Since microalgae may be grown using CO 2 from biomass combustion, discovery of their advantages as a binder in briquetting is particularly welcome.
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effects of operating variables on durability of fuel briquettes from rice husks and corn cobs
Fuel Processing Technology, 2015Co-Authors: J A StegemannAbstract:Abstract Biomass densification processes increase fuel energy density for more efficient transport. This study presents new data to show that blending different types of biomass improves the properties of densified biomass briquettes. The specific objectives were to investigate the effects of sample batch (biomass source), material ratio (rice husks to corn cobs), addition of binder (starch and water mixture) and Compaction Pressure, on briquette properties, using a factorial experiment. Briquettes had a unit density of up to 1.9 times the loose biomass bulk density, and were stronger than briquettes from the individual materials. Considering average values from two biomass sources, an unconfined compressive strength of 176 kPa was achieved at a Compaction Pressure of 31 MPa for a 3:7 blend of rice husks to corn cobs with 10% binder. These briquettes were durable, with only 4% mass loss during abrasion and 10% mass loss during shattering tests. They absorbed 36% less water than loose corn cobs. Statistical analysis of the results showed that starch and water addition was required for adequate briquette strength, but significantly reduced green and relaxed densities. The source of the biomass had a significant effect on densification, which emphasises the need to understand factors underlying biomass variability.
Junxia Jiang - One of the best experts on this subject based on the ideXlab platform.
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modeling and experimental validation of Compaction Pressure distribution for automated fiber placement
Composite Structures, 2021Co-Authors: Junxia Jiang, Han WangAbstract:Abstract Automated fiber placement is especially suitable for manufacturing composite components with curved surfaces, in which case the uneven Compaction Pressure distribution is an important factor affecting layup quality, but it has not been widely explored. In this paper, a theoretical model of the Compaction Pressure distribution for layup on irregular curved surface is established by analyzing the contact between the Compaction roller and prepreg layers. Based on the model, a numerical algorithm for calculating the Pressure distribution in the whole placement process is proposed. Then the Pressure distribution around four path points of a winglet mold is obtained and validated by the subsequent experiment. The results show that the model can be used to predict the Compaction Pressure distribution before the placement and analyze the layup quality and defects from the perspective of Compaction Pressure.
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Pressure distribution for automated fiber placement and design optimization of Compaction rollers
Journal of Reinforced Plastics and Composites, 2019Co-Authors: Junxia JiangAbstract:During automated fiber placement, insufficient Compaction Pressure leads to low bond strength between layers and may cause defects like bridging. The Compaction roller contacts the prepreg and affe...
Han Wang - One of the best experts on this subject based on the ideXlab platform.
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modeling and experimental validation of Compaction Pressure distribution for automated fiber placement
Composite Structures, 2021Co-Authors: Junxia Jiang, Han WangAbstract:Abstract Automated fiber placement is especially suitable for manufacturing composite components with curved surfaces, in which case the uneven Compaction Pressure distribution is an important factor affecting layup quality, but it has not been widely explored. In this paper, a theoretical model of the Compaction Pressure distribution for layup on irregular curved surface is established by analyzing the contact between the Compaction roller and prepreg layers. Based on the model, a numerical algorithm for calculating the Pressure distribution in the whole placement process is proposed. Then the Pressure distribution around four path points of a winglet mold is obtained and validated by the subsequent experiment. The results show that the model can be used to predict the Compaction Pressure distribution before the placement and analyze the layup quality and defects from the perspective of Compaction Pressure.