• Title, Summary, Keyword: Volume Fraction

검색결과 2,152건 처리시간 0.049초

Al Shee/CFRP 다적층 하이브리드 복합재료의 굴곡강도에 미치는 카본섬유 체적률 및 배열방향 영향 (The Influence of Volume Fraction and Fiber Orientation of CERP Layer on Flexural properties of A17075/CFRP Multi-Layered Hybrid Laminate Material)

  • 유재환
    • 한국안전학회지
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    • v.19 no.4
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    • pp.31-35
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    • 2004
  • The A17075/CFRP multi-layered hybrid laminate material consists of the alternating A17075-T6 sheets and carbon/epoxy prepregs of M40 fade. The influence of volume fraction and fiber orientation of A17075/CFRP layer on flexural properties of A17075/CFRP laminate alternating A17075-T6 and carbon/epoxy prepreg was investigated. The results obtained from the experimental analysis are as follows: 1. In the $0^{\circ}$ fiber orientation, the mont of increase of the flexural rigidity was $20.5\%$ at the $26.5\%$ volume fraction and $38.0\%\;at\;the\;35.7\%$ volume fraction compared with the flexural rigidity level(20.0GPa) of the $10\%$ volume fraction of CFRP. 2. In the $\pm45^{\circ}$ fiber orientation the amount of decrease of the flexural rigidity was $23.5\%\;at\;the\;20.0\%$ volume fraction and $31.5\%\;at\;the\;33.3\%$ volume fraction compared with the flexural rigidity level of the $10\%$ volume fraction of CFRP. 3. In the $0^{\circ}$ fiber orientation, the flexural strength was 481.5MPa at the $10\%$ volume fraction of CFRP and 583.8MPa at the $26.5\%$ volume fraction and 653.7MPa at the $35.7\%$ volume faction. 4. In the $\pm45^{\circ}$ fiber orientation, the flexural strength was 354.0MPa at the $20.0\%$ volume fraction of CFRP and 340.5MPa at the $33.3\%$ volume fraction.

오스테나이트계 316L 스테인리스강의 강도 및 감쇠능에 미치는 미세조직의 영향 (The Effects of Microstructure in Austenitic 316L Stainless Steels on the Strength and Damping Capacity)

  • 손동욱;이종문;김효종;남기우;박규섭;강창룡
    • 한국해양공학회지
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    • v.20 no.1
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    • pp.1-6
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    • 2006
  • The effects of microstructure on the damping capacity and tensile properties of 316L stainless steel were investigated. Increasing the degree of cold working, the volume fraction of $\varepsilon-martensite$ decreased after rising to maximum value at specific level of cold working, the volume fraction of d-martensite slowly increased and then dramatically increased from the point of decreasing $\varepsilon-martensite$ volume fraction. Increasing the degree of cold working, the behnvior of damping capacity is similar to that of the $\varepsilon-martensite$. After the damping capacity showing the maximum value at about $20\%$ of cold rolling, damping capacity was decreased with the volume fraction of $\varepsilon-martensite$. Tensile strength was proportional to the volume fraction of d-martensite, and elongation steeply decreased in the range low volume fraction of a'-martensite, then slowly decreased in range the above $10\%$ volume fraction of d-martensite. The damping capacity and elongation is strongly controlled by the volume fraction of $\varepsilon$ martensite with liner relationship. However, the effect of the volume fraction of d-martensite and austenite phase on the damping capacity was not observed. Tensile strength was governed by the volume fraction of d-martensite.

Local nanofiller volume concentration effect on elastic properties of polymer nanocomposites

  • Shin, Hyunseong;Han, Jin-Gyu;Chang, Seongmin;Cho, Maenghyo
    • Multiscale and Multiphysics Mechanics
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    • v.1 no.1
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    • pp.65-76
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    • 2016
  • In this study, an influence of local variation of nanoparticulate volume fraction on the homogenized elastic properties is investigated. It is well known that interface effect is dependent on the radius and volume fraction of reinforced nanofillers. However, there is no study on the multiscale modeling and analysis of polymer nanocomposites including polydispersed nanoparticles with consideration of interphase zone, which is dependent on the volume fraction of corresponding nanoparticles. As results of numerical examples, it is confirmed that an influence of local variation of nanoparticulate volume fraction should be considered for non-dilute system such as cluster of nanoparticles. Therefore representative volume element analysis is conducted by considering local variation of nanoparticle volume fraction in order to analyze the practical size of cell including hundreds of nanoparticles. It is expected that this study could be extended to the multiparticulate nanocomposite systems including polydispersed nanoparticles.

Effect of steel fiber volume fraction and aspect ratio type on the mechanical properties of SIFCON-based HPFRCC

  • Kim, Seugnwon;Jung, Haekook;Kim, Yongjae;Park, Cheolwoo
    • Structural Engineering and Mechanics
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    • v.65 no.2
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    • pp.163-171
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    • 2018
  • Plain concrete is a brittle material with a very low tensile strength compared to compressive strength and critical tensile strain. This study analyzed the dynamic characteristics of high-performance fiber-reinforced cementitious composites based on slurry-infiltrated fiber concrete (SIFCON-based HPFRCC), which maximizes the steel-fiber volume fraction and uses high-strength mortar to increase resistance to loads, such as explosion and impact, with a very short acting time. For major experimental variables, three levels of fiber aspect ratio and five levels of fiber volume fraction between 6.0% and 8.0% were considered, and the flexural strength and toughness characteristics were analyzed according to these variables. Furthermore, three levels of the aspect ratio of used steel fibers were considered. The highest flexural strength of 65.0 MPa was shown at the fiber aspect ratio of 80 and the fiber volume fraction of 7.0%, and the flexural strength and toughness increased proportionally to the fiber volume fraction. The test results according to fiber aspect ratio and fiber volume fraction revealed that after the initial crack, the load of the SIFCON-based HPFRCC continuously increased because of the high fiber volume fraction. In addition, sufficient residual strength was achieved after the maximum strength; this achievement will bring about positive effects on the brittle fracture of structures when an unexpected load, such as explosion or impact, is applied.

슈퍼 2상 스테인리스강의 미세조직 및 기계적 성질에 미치는 시효의 영향 (Effect of Aging on the Microstructure and Mechanical Properties in Super Duplex Stainless Steel)

  • 김수천;강창룡
    • 한국해양공학회지
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    • v.23 no.3
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    • pp.40-45
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    • 2009
  • With the increase in the annealing temperature, the volume fraction of austenite phase increased and the volume fraction of ferrite phase decreased. In compliance with the addition of N, not only the volume fraction of austenite phase was increased but also the austenite structure was made larger. Volume fraction of ${\sigma}$ phase was increased by decreasing of the volume fraction of ferrite phase, with the increase in the aging time and in compliance with the addition of N. As increasing in volume fraction of ${\sigma}$ phase, tensile strength and hardness increased, while elongation and impact value decreased. Elongation slowly decreased and impact value rapidly decreased at the early stage of aging. By the added N, tensile strength, elongation, hardness and impact value was increased.

Fe-Mn 계 합금에서 비부피 차를 이용한 ${\varepsilon}$ 마르텐사이트의 부피분율 측정 (Measurement of Volume Fraction of ${\varepsilon}$ Martensite using Specific Volume Difference in Fe-Mn Based Alloys)

  • 지광구;한준현;장우양
    • 열처리공학회지
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    • v.16 no.4
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    • pp.211-215
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    • 2003
  • In this work, a new way of measuring the volume fraction of e martensite in Fe-based alloys has been proposed. Since the specific volume of ${\varepsilon}$ martensite, depending on alloy composition, is smaller than that of austenite i.e ${\gamma}$ phase, volume expansion takes place during ${\varepsilon}{\rightarrow}{\gamma}$ reverse transformation. As the amount of the volume expansion is proportional to the product of specific volume difference times the volume fraction of ${\varepsilon}$ martensite, the volume fraction of ${\varepsilon}$ martensite can be calculated by measuring the volume expansion and the specific volume difference. Such a relationship was confirmed in Fe-21Mn and Fe-32Mn-6Si alloys which undergo ${\gamma}{\rightarrow}{\varepsilon}$ martensitic transformation on cooling and by cold rolling, respectively. It was also found that the former has isotropic ${\varepsilon}$ martensite while the latter has anisotropic ${\varepsilon}$ martensite.

Free vibration of imperfect sigmoid and power law functionally graded beams

  • Avcar, Mehmet
    • Steel and Composite Structures
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    • v.30 no.6
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    • pp.603-615
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    • 2019
  • In the present work, free vibration of beams made of imperfect functionally graded materials (FGMs) including porosities is investigated. Because of faults during process of manufacture, micro voids or porosities may arise in the FGMs, and this situation causes imperfection in the structure. Therefore, material properties of the beams are assumed to vary continuously through the thickness direction according to the volume fraction of constituents described with the modified rule of mixture including porosity volume fraction which covers two types of porosity distribution over the cross section, i.e., even and uneven distributions. The governing equations of power law FGM (P-FGM) and sigmoid law FGM (S-FGM) beams are derived within the frame works of classical beam theory (CBT) and first order shear deformation beam theory (FSDBT). The resulting equations are solved using separation of variables technique and assuming FG beams are simply supported at both ends. To validate the results numerous comparisons are carried out with available results of open literature. The effects of types of volume fraction function, beam theory and porosity volume fraction, as well as the variations of volume fraction index, span to depth ratio and porosity volume fraction, on the first three non-dimensional frequencies are examined in detail.

複合組織鋼의 衝擊破壞擧動에 영향 을 주는 마르텐사이트 體積率의 效果 (Effects of the Martensive Volume Fraction on the Behavior of Impact Fracture of Dual Phase Steels)

  • 송삼홍;오택열;장두수
    • 대한기계학회논문집
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    • v.7 no.4
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    • pp.372-378
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    • 1983
  • Use of dual phase steel are growing for its high strength and light weight in automobiles. The effect of the martensite volume fraction with various impact velocities on the strength, ductility and absorbed energy of dual phase (ferrite-martensite) steels were investigated in low carbon 1.5% Mn steels which were soaked at 700.deg. C, 730.deg. C, 780.deg. C, and brine quenched. Both the yield load and the maximum impact load increased when the martensite volume fraction increased, the loading time and the absorbed energy of the specimen decreased when the martensite volume fraction increased.

입자 함유율의 변화에 따른 나노 실리카 복합재료의 마모 특성 (Wear characteristics on particle volume fraction of nano silica composite materials)

  • 이정규;고성위
    • 수산해양기술연구
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    • v.49 no.4
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    • pp.492-499
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    • 2013
  • The characteristics of abrasive wear of the rubber matrix composites filled with nano sized silica particles were investigated at ambient temperature by pin-on-disc friction test. The range of volume fraction of silica particles tested are between 11% to 25%. The cumulative wear volume and friction coefficient of these materials on particle volume fraction were determined experimentally. The major failure mechanisms were lapping layers, deformation of matrix, ploughing, deboding of particles and microcracking by scanning electric microscopy photograph of the tested surface. The cumulative wear volume showed a tendency to increase nonlinear with increase of sliding distance. As increasing the silica particles of these composites indicated higher friction coefficient.

압전복합재료의 제작 및 음향특성 고찰 (A Study on the Fabrication and Acoustic Properties of Piezocomposites)

  • 이상욱;남효덕;류정탁;김연보
    • 한국전기전자재료학회:학술대회논문집
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    • pp.35-38
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    • 2003
  • In this paper, we investigated the electric and acoustic properties of piezoelectric composites, which were fabricated using polymer and piezoelectric ceramics, when the volume fraction of PZT varies. Practically, the shrinkage rate of polymer is an important factor in ultrasonic transducer fabrication. When 10 wt% filler A was added into polymer(Epofix), the lowest shrinkage was resulted. The electromechanical coupling factor($k_t$) of the fabricated piezoelectric composites showed its highest when the volume fraction PZT was 0.6. It decreased if the volume fraction was higher than the value. The relative permittivity and acoustic impedance of piezoelectric composites decreased linearly when PZT volume fraction was decreased. The lowest acoustic impedance was 3.2 when the volume fraction of PZT was 0.2.

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