• Title/Summary/Keyword: glass fiber orientation

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SALS Study on Transcrystallization and Fiber Orientation in Glass Fiber/Polypropylene Composites

  • Na, Kun;Park, Han-Soo;Won, Hong-Youn;Lee, Jong-Kwan;Lee, Kwang-Hee;Nam, Joo-Young;Jin, Byung-Suk
    • Macromolecular Research
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    • v.14 no.5
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    • pp.499-503
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    • 2006
  • This report presents a new technical approach for evaluating the fiber orientation of composites using small-angle light scattering (SALS). Glass fiber (GF)/polypropylene (PP) composites with different fiber orientations were prepared by drawing compression-molded specimens. The drawn samples were remelted and then annealed at $150^{\circ}C$ in order to induce a crystalline structure on the fiber surface, and then underwent SALS analysis. The samples showed a combination of circular and streak patterns. The model calculations demonstrated that the number of nuclei on the fiber surface and the thickness of the transcrystalline layer affected the sharpness and intensity of the streak pattern. In addition, the azimuthal angle of the streak pattern was found to be dependent on the direction of the transcrystalline layer, which correlated with the fiber direction. This correlation suggests that the fiber orientation in the composites can be easily evaluated using SALS.

Influences of Fiber Laminate Orientation on the Behavior of Fatigue Delamination in GLARE (GLARE 의 섬유층 배향이 피로층간분리 거동에 미치는 영향)

  • 황진우;송삼홍;김철웅
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2004.10a
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    • pp.479-482
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    • 2004
  • The behavior of fatigue delamination in a GLARE(Glass Fiber Reinforced Metal Laminates) under fatigue loading conditions investigated. The behavior of fatigue delamination was examined basing on investigation of the crack and delamination using a SAM (Scanning Acoustic Microscope). The crack and delamination behavior on the relationship among a-N, SAM images and crack length-delamination length were considered. The test results indicated the features of different fatigue delamination and crack growth according to each fiber orientation angle and also obtained to more increase delamination than crack through the relationship between crack length and delamination length in GLARE.

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An Experimental Study on Shear Strengthening of Concrete Deep Beams with Glass Fiber Sheets (유리섬유보강재를 이용한 Deep Beam의 전단보강에 관한 실험적 연구)

  • Jo, Byoung-Wan;Kim, Young-Jin;Kim, Do
    • Proceedings of the Korea Concrete Institute Conference
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    • 1997.10a
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    • pp.609-614
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    • 1997
  • Recently, many researchers have performed R&D about strengthening of R/C with steel plates, carbon fiber sheets. aramid fiber sheets and glass fiber sheets, and so on. However most of research were limited in study of flexural strengthening of R/C beams. This paper shows the results of an experimental study on shear reinforcement of deep beams using Glass Fiber Sheet in relation to shear-span ratio. strengthening orientation and anchorage. The results prove that shear failure is governed by reinforced orientation. adherence and anchorage. Additional anchorage of fibers does not only cause the improvement in the internal resistance, but also control the brittle shear failure of specimen after reaching the maximum load.

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Frequency Spectrum and re Correlation with Cutting Mechanisms in Orthogonal Cutting of Glass Fiber Reinforced Plastics (GFRP의 2차원 절삭에서 주파수 스펙트럼과 절삭메카니즘과의 상호연관성에 관한 연구)

  • Gi-Heung Choi
    • Journal of the Korean Society of Safety
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    • v.16 no.3
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    • pp.135-142
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    • 2001
  • This study discusses frequency analysis based on the frequency spectrum and process characterization in orthogonal cutting of Fiber-matrix composite materials. A sparsely distributed idealized composite material, namely a glass reinforced polyester(GFRP) was used as workpiece The present method employs a force sensor and the signals from the sensor are processed using the fast Fourier transform(FFT) technique. The experimental correlations between the different chip formation mechanisms and power spectrum me established. Effects of fiber orientation, cutting parameters and tool geometry on the cutting mechanisms me also discussed.

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A Study on the Processing of Long Fiber-Reinforced Composite Materials for Thermoforming On the Correlation Coefficient between Separation and Orientation (Thermoforming용 長纖維强化 複合材料의 成形工程에 관한 硏究 分離$\cdot$配向의 相關계수)

  • 이동기;김정락;김상필;이우일;김이곤
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.17 no.5
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    • pp.1106-1114
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    • 1993
  • A composite material is composed of a reinforcement and a matrix, which determine mechanical characteristics of the molded part. There is no doubt that the properties of a composite material depend not only on the characteristics of the matrix but also on the structure of glass fiber mat and a fiber type of reinforcement. Therefore it is very important to study the composites of reinforcement and the matrix, and to control the fiber type in the process of molding of composite materials. In this study, the specimen was made of a glass fiber mat of 6-7mm thickness by scattering it in the air after cutting the glass fiber mat with needle punching makes change according to the type of needle and the number of times of stretching. First the sheet was made by means of a hot-press after accumulating a matrix and a glass fiber according to each mat structure of glass fiber. It was heated the manufactured sheet with the dry oven and molded it a secondary high temperature compression by a 30 ton oilhydraulic press. A definition of a correlation coefficient is showed up during this period and find it out with the relation of the fiber-matrix separation and the fiber orientation. We studied effects of the glass fiber mat structures on the correlation coefficient.

Coupled Analysis with Digimat for Realizing the Mechanical Behavior of Glass Fiber Reinforced Plastics (유리섬유 강화 플라스틱의 역학적 거동 구현을 위한 Digimat와의 연성해석 연구)

  • Kim, Young-Man;Kim, Yong-Hwan
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.32 no.6
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    • pp.349-357
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    • 2019
  • Finite element method (FEM) is utilized in the development of products to realistically analyze and predict the mechanical behavior of materials in various fields. However, the approach based on the numerical analysis of glass fiber reinforced plastic (GFRP) composites, for which the fiber orientation and strain rate affect the mechanical properties, has proven to be challenging. The purpose of this study is to define and evaluate the mechanical properties of glass fiber reinforced plastic composites using the numerical analysis models of Digimat, a linear, nonlinear multi-scale modeling program for various composite materials such as polymers, rubber, metal, etc. In addition, the aim is to predict the behavior of realistic polymeric composites. In this regard, the tensile properties according to the fiber orientation and strain rate of polybutylene terephthalate (PBT) with short fiber weight fractions of 30wt% among various polymers were investigated using references. Information on the fiber orientation was calculated based on injection analysis using Moldflow software, and was utilized in the finite element model for tensile specimens via a mapping process. LS-Dyna, an explicit commercial finite element code, was used for coupled analysis using Digimat to study the tensile properties of composites according to the fiber orientation and strain rate of glass fibers. In addition, the drawbacks and advantages of LS-DYNA's various anisotropic material models were compared and evaluated for the analysis of glass fiber reinforced plastic composites.

Microstructure and Impactive Flexural Vibration Characteristics of Glass-Fabric/Epoxy Composite Beams (유리직물/에폭시 복합재료 보의 내부구조와 충격굽힘진동특성)

  • 서지웅;최낙삼
    • Proceedings of the Korean Society For Composite Materials Conference
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    • 1999.04a
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    • pp.53.1-56
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    • 1999
  • The vibration behavior of glass-fabric reinforced plastic(GFRP) composite beams subjected to various transverse impacts has been investigated as a function of fiber orientation and void fraction. Theoretical results of resonant frequency damping coefficient and modal amplitude dispersion using the Euler-beam theory were obtained along with the finite element analysis which were compared with experimental ones Consequently it was shown that the transverse vibration characteristics were largely affected by fiber orientation and void fraction.

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Simulation and Evaluation of Compressive Strength of FRP According to the Winding Orientation of Glass Fiber (FRP에서 와인딩 각도에 따른 압축강도의 시뮬레이션과 특성평가)

  • Park, Hoy-Yul;Kang, Dong-Pil;Han, Dong-Hee;Kim, In-Sung;Pyo, Hyun-Dong
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2000.05b
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    • pp.250-253
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    • 2000
  • The fiber orientation in FRP has a great effect on the strength of FRP because the strength of FRP mainly depends on the strength of fiber. Unidirectional FRP made by pultrusion method has comparatively lower compressive strength than tensile strength. Compressive strength of unidirectional FRP may be increased by filament winding layer which has tensile stress when compressive stress was loaded. In this study, compressive strength and stresses of FRP rods were simulated according to the winding orientation of glass fiber. Inner part of FRP was made unidirectionally by pultrusion method and outer part of FRP was made by filament winding method. Simulated value and real evaluated compressive strength were compared to investigate stresses which is prominent to the fracture of FRP. The shear stresses had a great effect on the strength of FRP although the stress of parallel direction of FRP was much higher.

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Evaluation on Tensile Properties and Fracture Toughness of Glass Fiber/Aluminum Hybrid Laminates (유리섬유/알루미늄 혼성 적층판의 인장특성과 파괴인성 평가)

  • Woo Sung-Choong;Choi Nak-Sam
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.29 no.6 s.237
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    • pp.876-888
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    • 2005
  • Tensile properties and fracture toughness of monolithic aluminum, fiber reinforced plastics and glass fiber/aluminum hybrid laminates under tensile loads have been investigated using plain coupon and single-edge-notched specimens. Elastic modulus and ultimate tensile strength of GFMLs showed different characteristic behaviors according to the Al kind, fiber orientation and composition ratio. Fracture, toughness of A-GFML-UD which was determined by the evaluation of $K_{IC}$ and $G_{IC}$ based on critical load was similar to that of GFRP-UD and was much higher than monolithic Al. Therefore, A-GFML-UD presented superior fracture toughness as well as prominent damage tolerance in comparison to its constituent Al. By separating Al sheet from GFMLs after the test, optical microscope observation of fracture zone of GFRP layer in the vicinity of crack tip revealed that crack advance of GFMLs depended on the orientation of fiber layer as well as Al/fiber composition ratio.

Visualization Analysis of Correlation between Fiber Orientation Angles and Flow Patterns by Gate-Magnetization Method

  • Miyauchi, Hidekazu;Imade, Masaaki;Okada, Saburo;Yokoi, Hidetoshi
    • 제어로봇시스템학회:학술대회논문집
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    • 2001.10a
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    • pp.86.4-86
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    • 2001
  • This paper presents the results of a visualization analysis of the correlation between the fiber orientation and flow pattern in injection molding using the Gate-magnetization method developed for the precise visualization of melt flow. The results of the comparisons of the fiber orientation angles with the flow patterns by the Gate-Magnetization method for GPPS mixed with glass fibers show the strong correlation between the flow patterns and fiber orientation angles. According to forward movement of the flow, the fiber orientation patterns move toward the side walls following the flow patterns. These results elucidate that fibers are oriented in the expansion process of the melt, and ...

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