• Title/Summary/Keyword: particle-reinforced composites

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Incremental Damage Mechanics of Particle or Short-Fiber Reinforced Composites Including Cracking Damage

  • Cho, Young-Tae
    • Journal of Mechanical Science and Technology
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    • v.16 no.2
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    • pp.192-202
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    • 2002
  • In particle or short-fiber reinforced composites, cracking of the reinforcements is a significant damage mode because the cracked reinforcements lose load carrying capacity. This paper deals with an incremental damage theory of particle or short-fiber reinforced composites. The composite undergoing damage process contains intact and broken reinforcements in a matrix. To describe the load carrying capacity of cracked reinforcement, the average stress of cracked ellipsoidal inhomogeneity in an infinite body as proposed in the previous paper is introduced. An incremental constitutive relation on particle or short-fiber reinforced composites including progressive cracking of the reinforcements is developed based on Eshelby's (1957) equivalent inclusion method and Mori and Tanaka\`s (1973) mean field concept. Influence of the cracking damage on the stress-strain response of composites is demonstrated.

Damage Mechanics in Particle or short-Fiber Reinforced Composite (분산형 복합재료의 손상 메커니즘)

  • 조영태
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 1998.10a
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    • pp.287-292
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    • 1998
  • In particle or short-fiber reinforced composites. cracking of the reinforcements is a significant damage mode because the broken reinforcements lose load carrying capacity. This paper deals with the load carrying capacity of intact and broken ellipsoidal inhomogeneities embedded in an infinite body and a damage theory of particle or short-fiber reinforce composites. The average stress in the inhomogeneity represents its load carrying capacity. and the difference between the average stresses of the intact t and broken inhomogeneities indicates the loss of load carrying capacity due to cracking damage. The composite in damage process contains intact and broken reinforcements in a matrix. An incremental constitutive relation of particle or short-fiber reinforced composites including the progressive cracking damage of the reinforcements have been developed based on the Eshelby's equivalent inclusion method and Mori and Tanaka's mean field concept. Influence of the cracking damage on the stress-strain response of the composites is demonstrated.

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A Micromechanics-based Elastic Model for Particle-Reinforced Composites Containing Slightly Weakened Interfaces (미소한 손상경계면을 갖는 입자강화 복합재료의 미세역학 탄성 모델에 관한 연구)

  • Lee, Haeng-Ki;Pyo, Suk-Hoon
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2007.04a
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    • pp.441-444
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    • 2007
  • This paper presents a part of micormechanics-based elastic modeling (Lee and Pyo, 2007) of particle-reinforced composites containing slightly weakened interfaces. The Eshelby's tensor for a damaged ellipsoidal inclusion to model particles with slightly weakened interfaces is incorporated into a micormechanical formulation by Ju and Chen (1994). A damage model in accordance with the Weibull's probabilistic function is also developed to simulate the progression of weakened interface in the composites.

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Effect of particle size on graphite reinforced conductive polymer composites (입자의 크기에 따른 흑연 보강 전도성 고분자 복합재료의 특성 연구)

  • Heo, S.I.;Yun, J.C.;Oh, K.S.;Han, K.S.
    • Proceedings of the Korean Society For Composite Materials Conference
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    • 2005.04a
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    • pp.257-260
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    • 2005
  • Graphite reinforced conductive polymer composites were fabricated by the compression molding technique. Graphite powder was mixed with an phenol resin to impart electrical property in composites. The ratio and particle size of graphite powder were varied to investigate electrical conductivity of cured composites. In this study, graphite reinforced conductive polymer composites with high filler loadings(>66wt.%) were manufactured to accomplish high electrical conductivity. With increasing the loading ratio of graphite powder, the electrical conductivity and flexural strength increased. However. above 80wt.% filler loadings, flexural strength decreased due to lack of resin. Regardless of graphite particle size, electrical conductivity wasn’t varied. On the other hand, with decreasing particle size, flexural strength increased due to high specific surface area.

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Strength Analysis of Particle-Reinforced Aluminum Composites with Length-Scale Effect based on Geometrically Necessary Dislocations (기하적 필수 전위에 의한 길이효과를 고려한 입자 강화 알루미늄 복합재의 강도해석)

  • Sub, Y.S.;Kim, Y.B.;Rhee, Z.K.
    • Transactions of Materials Processing
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    • v.18 no.6
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    • pp.482-487
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    • 2009
  • A finite element based microstructural modeling for the size dependent strengthening of particle reinforced aluminum composites is presented. The model accounts explicitly for the enhanced strength in a discretely defined "punched zone" around the particle in an aluminum matrix composite as a result of geometrically necessary dislocations developed through a CTE mismatch. The density of geometrically necessary dislocations is calculated considering volume fraction of the particle. Results show that predicted flow stresses with different particle size are in good agreement with experiments. It is also shown that 0.2% offset yield stresses increases with smaller particles and larger volume fractions and this length-scale effect on the enhanced strength can be observed by explicitly including GND region around the particle. The strengths predicted with the inclusion of volume fraction in the density equation are slightly lower than those without.

Incremental Theory of Reinforcement Damage in Discontinuously-Reinforced Composite (분산형 복합재료의 강화재 손상 증분형 이론)

  • 김홍건
    • Proceedings of the Korean Society of Marine Engineers Conference
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    • 2000.05a
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    • pp.122-126
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    • 2000
  • In particle or short-fiber reinforced composites cracking of the reinforcements is a significant damage mode because the broken reinformcements lose load carrying capacity . The average stress in the inhomogeneity represents its load carrying capacity and the difference between the average stresses of the intact and broken inhomogeneities indicates the loss of load carrying capacity due to cracking damage. The composite in damage process contains intact and broken reinforcements in a matrix, An incremental constitutive relation of particle or short-fiber reinforced composites including the progressive cracking damage of the reinforcements have been developed based on the Eshelby's equivalent inclusion method and Mori-Tanaka's mean field concept. influence of the cracking damage on the Eshelby's equivalent inclusion method and Mori-Tanaka's mean field concept. Influence of the cracking damage on the stress-strain response of the composites is demonstrated.

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A Micromechanics based Elastic Constitutive Model for Particle-Reinforced Composites Containing Weakened Interfaces and Microcracks (계면손상과 미세균열을 고려한 입자강화 복합재료의 미세역학 탄성구성모델)

  • Lee, Haeng-Ki;Pyo, Suk-Hoon;Kim, Hyeong-Ki
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.21 no.1
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    • pp.51-58
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    • 2008
  • A constitutive model based on a combination of a micromechanics-based weakened interface elastic model (Lee and Pyo, 2007) and a crack nucleation model (Karihaloo and Fu, 1989) is proposed to predict the effective elastic behavior of particle-reinforced composites. The model specifically considers imperfect interfaces in particles and microcracks in the matrix. To exercise the proposed constitutive model and to investigate the influence of model parameters on the behavior of the composites, numerical simulations on uniaxial tension tests were conducted. Furthermore, the present prediction is compared with available experimental data in the literature to verify the accuracy of the proposed constitutive model.

Dry Sliding Tribological Characteristics of SiC Particle-reinforced Aluminum Composites in Brakes

  • Yue, Chen;Baolin, Dai;Bao, Shangguan;Yongzhen, Zhang;Lemin, Sun
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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    • 2002.10b
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    • pp.417-418
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    • 2002
  • The dry sliding tribological characteristics were investigated using SiC particle-reinforced aluminum composites against semi-metallic frictional materials. The experimental results have indicated that, whether under the condition of continuous braking or not, the wear rates of SiC particle reinforced composites are much less than that of gray cast iron which is used as one of the common brake disk materials. At the same time, their frictional coefficients are about the same.

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High temperature and damping properties of squeeze cast Mg hybrid Metal Matrix Composites. (하이브리드 Mg 복합재료의 진동 감쇠능 및 고온 특성평가)

  • 장재호;김봉룡;최일동;조경목;박익민
    • Proceedings of the Korean Society For Composite Materials Conference
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    • 2002.10a
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    • pp.143-146
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    • 2002
  • Mg alloy is the lightest material of structural materials and is noticed for lightweight automotive parts because of excellent castability, superior ductility and damping capacity than Al alloy. But Mg Alloy is poor corrosion resistance and high temperature creep properties. In this study, Mg Matrix Composites were fabricated by squeeze casting method to improve high temperature creep properties and damping capacity. Hybrid Mg composites reinforced with Alborex, graphite particle, and SiCp was improved creep properties and damping capacity compared with Mg alloy. Compared to the length ($9\mu\textrm{m}, 27\mu\textrm{m}, 45\mu\textrm{m} etc.$), Hybrid Mg composites reinforced with SiCp, one of the most superior of the length and Alborex were more superior than those reinforced with graphite particle and Alborex in mechanical properties, creep characteristics, and damping capacity, etc.

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In-situ Crack Propagation Observation of a Particle Reinforced Polymer Composite Using the Double Cleavage Drilled Compression Specimens

  • Lee Yeon-Soo;Yoon Young-Ki;Jeong Bo-Young;Yoon Hi-Seak
    • Journal of Mechanical Science and Technology
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    • v.20 no.3
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    • pp.310-318
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    • 2006
  • In this study, we investigate the feasibility of in-situ crack propagation by using a double cleavage drilled compression (DCDC) specimen showing a slow crack velocity down to 0.03 mm/s under 0.01 mm/s of displacement control. Finite element analysis predicted that the DCDC specimens would show at least 4.3 fold delayed crack initiation time than conventional tensile fracture specimens under a constant loading speed. Using DCDC specimens, we were able to observe the in-situ crack propagation process in a particle reinforced transparent polymer composite. Our results confirmed that the DCDC specimen would be a good candidate for the in-situ observation of the behavior of particle reinforced composites with slow crack velocity, such as the self-healing process of micro-particle reinforced composites.