• Title, Summary, Keyword: Volume Fraction

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Mechanical Properties of Permeable Polymer Concrete for Permeability Pavement with Recycled Aggregate and Fiber Volume Fraction (재생골재 및 섬유 혼입률에 따른 포장용 투수성 폴리머 콘크리트의 역학적 특성)

  • Sung, Chan-Yong;Kim, Young-Ik
    • Journal of The Korean Society of Agricultural Engineers
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    • v.52 no.1
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    • pp.69-77
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    • 2010
  • Research on permeable pavement like asphalt and concrete pavement with porous structure has been increasing due to environmental and functional need such as reduction of run off and flood, and increase and purification of underwater resource. This study was performed to evaluate permeability, strengths and durability of permeable polymer concrete (PPC) using recycled aggregate that is obtained from waste concrete. Also, 6mm length of polypropylene fiber was used to increase toughness and interlocking between aggregate and aggregate surrounded by binder. In the test results, regardless of kinds of aggregates and fiber contents, the compressive strength and permeability coefficient of all types of PPC showed the higher than the criterion of porous concrete that is used in permeable pavement in Korea. Also, strengths of PPC with increase polypropylene fiber volume fraction showed slightly increased tendency due to increase binder with increase of fiber volume fraction. The weight reduction ratios for PPC after 300 cycles of freezing and thawing were in the range of 1.6~3.8 % and 2.2~5.6 %, respectively. The weight change ratio was very low regardless of the fiber volume fraction and aggregates. The weight reduction ratios of PPC with fiber and aggregate were in the range of 1.3~2.7 % and 2.2~3.2 % after 13 weeks and was very low regardless of the fiber volume fraction and aggregates.

High Strain-rate Deformation Behavior of NiAl/Ni Micro-laminated Composites (NiAl/Ni 미세적층복합재료의 고속변형거동)

  • Kim Hee-Yeoun;Kim Jin-Young;Jeong Dong-Seok;Enoki Manabu;Hong Soon-Hyung
    • Proceedings of the Korean Society For Composite Materials Conference
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    • pp.237-240
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    • 2004
  • High strain-rate deformation behavior of NiAl/Ni micro-laminated composites was characterized by split hopkins on pressure bar(SHPB). When the strain rate increased, the compressive stress of micro-laminated composites were increased a little. When the intermetallic volume fraction increased, the compressive stress of micro-laminated composites increased linearly irrespective of strain rate. Absorbed energy during the quasi-static and SHPB tests was calculated from the integrated area of stress-strain curve. Absorbed energy of micro-laminated composites deviated from the linearity in terms of the intermetallic volume fraction but merged to the value of intermetallic as the strain rate increased. This was due to high tendency of intermetallic layer for the localization of shear deformation at high strain rate. Microstructure showing adibatic shear band(ASB) confirmed that the shear strain calculated from the misalignment angle of each layer increased and ASB width decreased when the intermetallic volume fraction. Simulation test impacted by tungsten heavy alloy cylinder resulted that the absorbed energies multiplied by damaged volume of micro-laminated composites were decreased as the intermetallic volume fraction increased. Fracture mode were changed from delamination to single fracture when the intermetallic volume fraction and this results were good matched with previous results[l] obtained from the fracture tests.

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Numerical Analysis for Two-Dimensional Compressible and Two-Phase Flow Fields of Air-Water in Eulerian Grid Framework (2차원 압축공기-물의 압축성 이상 유동 수치 해석)

  • Park, Chan-Wook;Lee, Sung-Su
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.32 no.6
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    • pp.429-445
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    • 2008
  • Two-phase compressible flow fields of air-water are investigated numerically in the fixed Eulerian grid framework. The phase interface is captured via volume fractions of each phase. A way to model two phase compressible flows as a single phase one is found based on an equivalent equation of states of Tait's type for a multiphase cell. The equivalent single phase field is discretized using the Roe‘s approximate Riemann solver. Two approaches are tried to suppress the pressure oscillation phenomena at the phase interface, a passive advection of volume fraction and a direct pressure relaxation with the compressible form of volume fraction equation. The direct pressure equalizing method suppresses pressure oscillation successfully and generates sharp discontinuities, transmitting and reflecting acoustic waves naturally at the phase interface. In discretizing the compressible form of volume fraction equation, phase interfaces are geometrically reconstructed to minimize the numerical diffusion of volume fraction and relevant variables. The motion of a projectile in a water-filled tube which is fired by the release of highly pressurized air is simulated presuming the flow field as a two dimensional one, and several design factors affecting the projectile movement are investigated.

Mechanical Properties and Fracture Behavior of Cylindrical Shell Type for Unidirectional CFRP Composite Material under Tension Load (원통형 셀 구조를 갖는 한방향 CFRP 적층 복합재료의 정적인장파괴거동)

  • 오환섭
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • pp.273-278
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    • 1998
  • In this paper, basic micro-mechanical properties of unidirectional CFRP composite shell such as bonding strength, fiber volume fraction and void fraction are measured and tensile strength test is performed with a fixture. And then fracture surfaces are observed by SEM. In case of basic micro-mechanical properties, bonding strength is reduce with decreasing of radius of each ply in a shell for the effect of residual stress, fiber volume fraction is smaller than plate, and void fraction is vise versa. For these reason, tensile strength of shell is smaller than plate fabricated with same prepreg. For failure mode shell has many splitted part along its length, and it is assumed that this phenomenon is caused by the difference of bonding strength for residual stress.

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Effect of Volume Fraction of Fibers on the Mechanical Properties of a Lightweight Aggregate Concrete Reinforced with Polypropylene Fibers (섬유 혼입률에 따른 섬유보강 경량골재 콘크리트의 역학적 특성)

  • Lee, Haeng-Ki;Song, Su-Yong
    • Journal of the Korea Concrete Institute
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    • v.18 no.6
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    • pp.743-748
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    • 2006
  • This paper presents results of an experimental study conducted to investigate the effect of volume fraction of fibers on the mechanical properties of a fiber-reinforced, lightweight aggregate concrete(FRLAC) that was produced without an autoclave process. The FRLAC enhanced the strength of lightweight, cellular concrete by adding polypropylene fibers and lightweight aggregates. To investigate the effect of volume fraction of fibers on the mechanical behavior of FRLAC and to determine the optimal volume fraction of fibers, a series of compression and flexural strength tests on FRLAC specimens with various fiber volume fractions(0%, 0.10%, 0.25%, 0.50%) were conducted. It was observed from the tests that a 0.25% volume fraction of fibers maximized the increase in the strength of FRLAC and the fibers controlled cracking in FRLAC.

Theoretical Analysis of Heat Pipe Thermal Performance According to Nanofluid Properties (나노유체 특성에 따른 히트파이프 성능해석)

  • Lim, Seung Min
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.39 no.7
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    • pp.599-607
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    • 2015
  • In this study, we theoretically investigate the thermal performances of heat pipes that have different nano-fluid properties. Two different types of nano-particles have been used: $Al_2O_3$ and CuO. The thermal performances of the heat pipes are observed for varying nano-particle aggregations and volume fractions. Both the viscosity and the conductivity increase as the volume fraction and the aggregation increase, respectively. Increasing the volume fraction helps increase the capillary limit in the well-dispersed condition. Whereas, the capillary limit is decreased under the aggregate condition, when the volume fraction increases. The dependence of the heat pipe thermal resistance on the volume fraction, aggregation, and conductivity of the nano-particles is analyzed. The maximum thermal transfer of the heat pipe is highly dependent on the volume fraction because of the high permeability of the heat pipe. For the proposed heat pipe, the optimum volume fraction of the nano-particle can be seen through 3D graphics.

Measurements of Soot Volume Fraction Using Laser Induced Incandescence (레이저 유도 백열법을 이용한 화염 내부 매연 농도 측정)

  • Lee, Seung;Lee, Sang-Hup;Lee, Byeong-Jun;Hahn, Jae-Won
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.24 no.5
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    • pp.725-732
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    • 2000
  • Laser induced incandescence (LII) method is frequently used to measure soot volume fraction in flames. In this study, experiments were performed to measure soot volume fraction in coaxial diffusion flame using LII method and calibrated with laser scattering/extinction method. The effects of laser intensity (>$1{\times}10^8W/cm^2$), laser wavelength (532nm, 1064nm) and detection wavelength (400nm, 600nm) on the LII signal were investigated. On the range of $4{\times}10^8{\sim}8{\times}10^8W/cm^2$ there were no effects of laser intensity on LII signal. Except these ranges, LII signal was increased with laser intensity. For the long gate width, the LII signals of the higher laser intensity (>${\vartheta}(GW/cm^2)$) cases had better correlation with soot volume fraction which were measured by laser extinction method compared with lower laser intensity cases. The errors of 2-dimensional cases at the calibration height were approximately 50% regardless of laser wavelength.

A Study on the Soot Particle Measurement in Co-flow Diffusion Flame Using a Laser Diagnostics and a Thermocouple (레이저 및 열전대를 이용한 동축류 확산화염에서의 매연입자 측정에 관한 연구)

  • Han, Yong-Taek;Lee, Ki-Hyung;Lee, Won-Nam
    • Proceedings of the KSME Conference
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    • pp.1267-1273
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    • 2004
  • The temperature and soot particle measurement technique in a laminar diffusion flame have been studied to investigate the characteristics of soot particle with temperature using a co-flow burner. The temperature distributions in the flame were measured by rapid insertion of a R-type thermocouple and the soot particles were detected were detected by LEM/LIS techniques. In these measurement, soot volume fraction, number density and soot diameters were analyzed experimentally. As a results, the spacial distributions of particle volume fraction, soot diameter, and number density are mapped throughout the flame using the Rayleigh theory for the scattering of light by absorbing particles. A laser extinction method was used to measure the soot volume fraction and Laser induced scattering method was used to measure the soot particle diameter and number density. Also, we measured temperature without the effect of soot particles attached to the thermocouple junction, which is close to the nozzle. In this result, we found that upstream zone has a unstable flowing in co-flow diffusion flame and the y-axis temperature of flame has a uniform temperature distribution in the most soot volume fraction zone.

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A Study on the Soot Particle Measurement in Co-Flow Diffusion Flame Using a Laser Diagnostics and a Thermocouple (레이저 및 열전대를 이용한 동축류 확산화염에서의 매연입자 측정에 관한 연구)

  • Han, Yong-Taek;Lee, Ki-Hyng;Lee, Won-Nam
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.28 no.7
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    • pp.863-870
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    • 2004
  • The temperature and soot particle measurement technique in a laminar diffusion flame has been studied to investigate the characteristics of soot particle with temperature using a co-flow burner. The temperature distribution in the flame were measured by rapid insertion of a R-type thermocouple and the soot particles by LEM/LIS techniques. In these measurement, soot volume fraction, number density and soot diameters were analyzed experimentally. As a results, the spacial distributions of particle volume fraction, soot diameter, and number density are mapped throughout the flame using the Rayleigh theory for the scattering of light by particles. A laser extinction method was used to measure the soot volume fraction and laser induced scattering method was used to measure the soot particle diameter and number density. Also, we measured temperature without the effect of soot particles attached to the thermocouple junction, which is close to the nozzle. In this result, we found that upstream zone has a unstable flowing in co-flow diffusion flame and the y-axis temperature of flame has a uniform temperature distribution in the most soot volume fraction zone.

Effect of Cold Working on the Tensile Strength of Fe-26Mn-4Co-2Al Damping Alloy (Fe-26Mn-4Co-2Al 제진합금의 인장강도에 미치는 냉간가공의 영향)

  • Kang, Chang-Yong;Kim, Seong-Hwi;Jeong, Gyu-Seong
    • Journal of the Korea Society For Power System Engineering
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    • v.20 no.6
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    • pp.46-50
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    • 2016
  • This study was carried out to investigate the effect of cold working on the tensile strength of Fe-26Mn-4Co-2Al damping alloy. ${\alpha}^{\prime}$ and ${\varepsilon}$-martensite were formed by cold working, and martensite was formed with the specific direction and surface relief. With the increasing degree of cold rolling, volume fraction of ${\alpha}^{\prime}$-martensite was increased, whereas the volume fraction of ${\varepsilon}$-martensite was decreased after rising to maximum value at specific lever of cold rolling. Tensile strength was linearly increased with an increasing of degree of cold rolling. Tensile strength was strongly affected to the volume fraction of ${\varepsilon}$-martensite formed by cold working, but the effect of volume fraction of ${\varepsilon}$-martensite on the tensile strength was not observed.