• Title, Summary, Keyword: fiber model

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Effects of Dietary Fiber Extracted from Citrus (Citrus unshiu S. Marcoy) Peel on Physicochemical Properties of a Chicken Emulsion in Model Systems

  • Choi, Yun-Sang;Kim, Hyun-Wook;Hwang, Ko-Eun;Song, Dong-Heon;Kim, Hack-Youn;Lee, Mi-Ai;Yoon, Yo-Han;Kim, Cheon-Jei
    • Food Science of Animal Resources
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    • v.32 no.5
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    • pp.618-626
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    • 2012
  • Citrus (Citrus unshiu S. Marcoy) industry by-products were used as a source of dietary fiber, and the effects of dietary fiber extracted from citrus peel on the proximate composition, pH, color, protein solubility, cooking loss, emulsion stability, and apparent viscosity of a chicken emulsion in model systems were examined. Chicken emulsions were prepared by adding citrus peel fiber at four different concentrations (1, 2, 3, and 4%). The apparent viscosity, redness, and yellowness of the chicken emulsion with citrus peel fiber were higher than those of the control (p<0.05). The lightness values of the chicken emulsions were lower in treatments containing citrus peel fiber (p<0.05). Furthermore, moisture content, cooking loss, and emulsion stability of the chicken emulsion with 1-2% citrus peel fiber were higher than those of other treatments (p<0.05). Fat content was lower in the treatments with added citrus peel fiber than that in the control (p<0.05). Chicken emulsions with added citrus peel fiber had improved quality characteristics, and the best results were obtained for the chicken emulsion with 2% added citrus peel fiber.

Time-dependent and inelastic behaviors of fiber- and particle hybrid composites

  • Kim, Jeong-Sik;Muliana, Anastasia
    • Structural Engineering and Mechanics
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    • v.34 no.4
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    • pp.525-539
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    • 2010
  • Polymer matrix composites are widely used in many engineering applications as they can be customized to meet a desired performance while not only maintaining low cost but also reducing weight. Polymers can experience viscoelastic-viscoplastic response when subjected to external loadings. Various reinforcements and fillers are added to polymers which bring out more complexity in analyzing the timedependent response. This study formulates an integrated micromechanical model and finite element (FE) analysis for predicting effective viscoelastic-viscoplastic response of polymer based hybrid composites. The studied hybrid system consists of unidirectional short-fiber reinforcements and a matrix system which is composed of solid spherical particle fillers dispersed in a homogeneous polymer constituent. The goal is to predict effective performance of hybrid systems having different compositions and properties of the fiber, particle, and matrix constituents. A combined Schapery's viscoelastic integral model and Valanis's endochronic viscoplastic model is used for the polymer constituent. The particle and fiber constituents are assumed linear elastic. A previously developed micromechanical model of particle reinforced composite is first used to obtain effective mechanical properties of the matrix systems. The effective properties of the matrix are then integrated to a unit-cell model of short-fiber reinforced composites, which is generated using the FE. The effective properties of the matrix are implemented using a user material subroutine in the FE framework. Limited experimental data and analytical solutions available in the literatures are used for comparisons.

Modeling the polypropylene fiber effect on compressive strength of self-compacting concrete

  • Nazarpour, Mehdi;Asl, Ali Foroughi
    • Computers and Concrete
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    • v.17 no.3
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    • pp.323-336
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    • 2016
  • Although the self-compacting concrete (SCC) offers several practical and economic benefits and quality improvement in concrete constructions, in comparison with conventionally vibrated concretes confronts with autogenously chemical and drying shrinkage which causes the formation of different cracks and creates different problems in concrete structures. Using different fibers in the mix design and implementation of fibrous concrete, the problem can be solved by connecting cracks and micro cracks together and postponing the propagation of them. In this study an experimental investigation using response surface methodology (RSM) based on full factorial design has been undertaken in order to model and evaluate the polypropylene fiber effect on the fibrous self-compacting concrete and curing time, fiber percentage and fiber amount have been considered as input variables. Compressive strength has been measured and calculated as the output response to achieve a mathematical relationship between input variables. To evaluate the proposed model analysis of variance at a confidence level of 95% has been applied and finally optimum compressive strength predicted. After analyzing the data, it was found that the presented mathematical model is in very good agreement with experimental results. The overall results of the experiments confirm the validity of the proposed model and this model can be used to predict the compressive strength of fibrous self-compacting concrete.

Theoretical Study on the Strengthening Mechanism in Short Fiber Composites (단섬유 복합강화 메커니즘에 관한 이론적 연구)

  • 김홍건;최창용;노홍길
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • pp.295-300
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    • 2003
  • In discontinuous composite mechanics, shear lag theory is one of the most popular model because of its simplicity and accuracy. However, it does not provide sufficiently accurate strengthening predictions in elastic regime when the fiber aspect ratio is small. This is due to its neglect of stress transfer across the fiber ends and the stress concentrations that exist in the matrix regions near the fiber ends. To overcome this shortcoming, a more simplified shear lag model introducing the stress concentration factor which is a major function of modulus ratio is proposed. It is found that the proposed model gives a good agreement with finite element results and has the capability to correctly predict the values of intefacial shear stresses and local stress variations in the small fiber aspect ratio regime.

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Performance and modeling of high-performance steel fiber reinforced concrete under impact loads

  • Perumal, Ramadoss
    • Computers and Concrete
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    • v.13 no.2
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    • pp.255-270
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    • 2014
  • Impact performance of high-performance concrete (HPC) and SFRC at 28-day and 56-day under the action of repeated dynamic loading was studied. Silica fume replacement at 10% and 15% by mass and crimped steel fiber ($V_f$ = 0.5%- 1.5%) with aspect ratios of 80 and 53 were used in the concrete mixes. Results indicated that addition of fibers in HPC can effectively restrain the initiation and propagation of cracks under stress, and enhance the impact strengths and toughness of HPC. Variation of fiber aspect ratio has minor effect on improvement in impact strength. Based on the experimental data, failure resistance prediction models were developed with correlation coefficient (R) = 0.96 and the estimated absolute variation is 1.82% and on validation, the integral absolute error (IAE) determined is 10.49%. On analyzing the data collected, linear relationship for the prediction of failure resistance with R= 0.99 was obtained. IAE value of 10.26% for the model indicates better the reliability of model. Multiple linear regression model was developed to predict the ultimate failure resistance with multiple R= 0.96 and absolute variation obtained is 4.9%.

Bundle Flow Dynamics in Roll Drafting

  • You Huh;Kim, Jong S.
    • Proceedings of the Korean Fiber Society Conference
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    • pp.114-114
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    • 2003
  • Fiber bundles output from a draft operation have linear density irregularity. This study is dealing with modeling the dynamics of fiber bundle during roll drafting based on continuity, momentum balance, and a constitutive assumption. The simulation results from this model are compared with experimental results and analyzed by applying the concept of the Describing Function(DF). It can be confirmed that the simulation results agree well with experiments in a steady state, if the model parameters are good adjusted.

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Design Model of Intensity Modulation Type Displacement sensor Using Step-index Multimode Optical Fiber (스텝 인덱스 멀티모드 광섬유를 이용한 광강도 변조방식 변위센서 설계모델 연구)

  • Shin, Woo-Cheol;Hong, Jun-Hee
    • Korean Journal of Optics and Photonics
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    • v.17 no.6
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    • pp.500-506
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    • 2006
  • An optical fiber displacement sensor has the advantages of relatively simplicity, cheap, small probe size and immunity against environmental perturbation. The working principle of the sensor is based on the intensity modulation that is detection light intensity reflecting from the surface being measured. This paper presents the mathematical model of displacement measurement mechanism of this sensor type. The theoretical and experimental data are compared to verify the model in describing the realistic approach to sensor design. Finally, the analysis results show that displacement response characteristics such as sensitivity, measuring range are easily modified by principal design parameters such as magnitude of optical Power, diameter of optical fiber core and distance between transmitting fiber and receiving fiber.

Tensile Behavior of Fiber/Particle Hybrid Metal Matrix Composites (섬유/입자 혼합금속복합재료의 인장거동)

  • 정성욱;정창규;한경섭
    • Proceedings of the Korean Society For Composite Materials Conference
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    • pp.139-142
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    • 2002
  • This study presents a mathematical model predicting the stress-strain behavior of fiber reinforced (FMMCs) and fiber/particle reinforced metal matrix composites (F/P MMCs). MMCs were fabricated by squeeze casting method using Al2O3 short fiber and particle as reinforcement, and A356 aluminum alloy as matrix. The fiber/particle ratios of F/P MMCs were 2:1, 1:1, 1:2 with the total reinforcement volume fraction of 20 vol.%, and the FMMCs were reinforced with 10 vol,%, 15 vol. %, 20 vol. % of fibers. Tensile tests were conducted and compared with predictions which were derived using laminate analogy theory and multi-failure model of reinforcements. Results show that the tensile strength of FMMCs with 10 vol.% of fiber was well matched with prediction, and as the fiber volume increases, predictions become larger than experimental results. The difference between the prediction and experiment is considered to be a result of matrix allowance of fiber damage in tensile loading. As the fiber volume fraction in FMMCs increases, the fiber damage increases and so that the tensile strength is reduced. The strength of F/P MMCs approaches more closely to the prediction than FMMCs reinforced with 20 vol.% of fibers because F/P MMCs contains small quantity of fibers and thus has a positive effect in fiber strengthening.

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Effects of Elastic Modulus Ratio on Internal Stresses in Short Fiber Composites (단섬유 복합체에서 탄성계수비가 내부응력에 미치는 영향)

  • 김홍건;노홍길
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.13 no.4
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    • pp.73-78
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    • 2004
  • The conventional SLT(Shear Lag Theory) which has been proven that it can not provide sufficiently accurate strengthening predictions in elastic regime when the fiber aspect ratio is small. This paper is an extented work to improve it by modifying the load transfer mechanism called NSLT(New Shear Lag Theory), which takes into account the stress transfer across the fiber ends and the SCF(Stress Concentration Factor) that exists in the matrix regions near the fiber ends. The key point of the model development is to determine the major controlling factor among the material and geometrical coefficients. It is found that the most affecting factor is the fiber/matrix elastic modulus ratio. It is also found that the proposed model gives a good result that has the capability to correctly predict the elastic properties such as interfacial shear stresses and local stress variations in the small fiber aspect ratio regime.

Finite Element Analysis of Concrete Columns Strengthened with Glass Fiber Sheets (유리섬유쉬트로 보강된 콘크리트 기둥의 유한요소해석)

  • 정택원;송하원;변근주
    • Proceedings of the Korea Concrete Institute Conference
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    • pp.449-454
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    • 2002
  • For finite analysis of concrete columns strengthened with glass fiber sheets, an effective concrete model which considers the confining effects by lateral reinforcement and glass fiber sheets is necessary. In this paper, the so-called elasto-plasticity and continuum fracture model (EPF model) is modified to consider high confining effects of strengthened reinforced concrete columns by introducing a simple correction factor ($\alpha$) which relates maximum lateral confining stress of the column to the evolution of deviatoric plasticity. Then, a finite element analysis is carried out for the strengthened reinforced concrete columns using the modified EPF model and equally spaced truss elements. It is shown that the, analysis predicts well the failure behavior of reinforced concrete columns strengthened with glass fiber sheets.

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