• Korean Journal of Materials Research
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• v.7 no.11
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• pp.951-956
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• 1997

Vacuum Hot Pressing을 이용하여 제조한 TiNi형상기억섬유 강화 6061 AI기지 복합재료를 제조하고 미세조직 및 기계적 특성 등을 연구하였다. 제조된 복합재의 항복응력은 예비변형량, 섬유체적율 및 열처리에 따라 증가하였다. 복합재의 지적특성은 예비변형이 가하여진 후 재가열되었을 때 기지 내 TiNi 섬유의 형상기억효과에 의한 압축잔류응력 발생에 기인된다. 미세조직 관찰 섬유와 기지 사이에는 AI$_{3}$Ti및 AI$_{3}$Ni의 금속간화합물층이 관찰되었다. 또한 시험온도 증가와 더불어 TiNi섬유강화된 복합재의 유동강도는 높은 값을 나타내었다.

• Polymer(Korea)
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• v.24 no.4
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• pp.459-468
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• 2000

To improve the mechanical properties of fiber-reinforced polymer matrix composites, laminated composites plates were fabricated using different matrix resins and glass or aramid fibers. The effect of matrix resin system were evaluated by tensile, flexural strength measurements. In the case of surface treated aramid fiber and unsaturated polyester resin composite, maximum flexural properties were observed in the composite prepared from the glass fiber treated with 0.5 wt% silane coupling agents. Vinylester resin composites show the highest tensile properties and isophthalic polyester composites have the highest flexural properties among the unsaturated polyester resin composites studied. The relationship between overlap laminated composites plates and mechanical properties of polymer composites is also investigated in order to improve mechanical properties of glass fiber and unsaturated polyester resin composites.

• 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.

• Composites Research
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• v.13 no.1
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• pp.50-60
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• 2000

This paper presents an analytical method considering tensile strength enhancement in hybrid $Al_2O_3$ fiber/particle/aluminum composites(MMCs). The tensile strength and elastic modulus of the hybrid MMCs are even 20% higher than those of the fiber reinforced MMCs with same volume fraction of reinforcements. This phenomenon is explained by the cluster model which is newly proposed in this research, and the strengthening mechanisms by a cluster is analyzed using simple modified rule of mixtures. From the analysis, it is observed that cluster structure in hybrid MMCs increase the fiber efficiency factor for the tensile strength and the orientation factor for the elastic modulus. The present theory is then compared with experimental results which was performed using squeeze infiltrated hybrid MMCs made of hybrid $Al_2O_3$ short fiber/particle preform and AC8A alloy as base metal, and the agreement is found to be satisfactory.

• Proceedings of the Korean Fiber Society Conference
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• 2001.10a
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• pp.330-333
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• 2001

일반적으로 하나 또는 그 이상의 입자상 충전재 흑은 섬유상 강화재와 연속상인 고분자 기재로 이루어진 고분자 복합재료는 물성이나 기능이 더욱 더 우수한 고성능/고기능성 고분자 재료에 대한 수요가 급격히 증대됨에 따라 이에 대한 많은 연구가 행해지고 있다[1,2]. 그러나 고분자 복합재료의 응력전달은 강화재와 고분자 기재의 계면을 통하여 일어나게 되므로 복합재료의 기계적 물성 등은 충전재의 양, 입자의 크기, 표면성질 뿐만 아니라 강화재와 고분자 기재 사이의 계면 접착력 또는 계면 성질에 크게 좌우된다. (중략)

• Composites Research
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• v.16 no.4
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• pp.74-79
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• 2003

Comparison of interfacial properties and microfailure mechanisms of oxygen-plasma treated poly(p-phenylene-2,6-benzobisoxazole(PBO. Zylon) and poly(p-phenylene terephthalamide)(PPTA, Kevlar) fibers/ epoxy composites were investigated using micromechanical technique and nondestructive acoustic emission(AE). Interfacial shear strength(IFSS) and work of adhesion, Wa of PBO or Kevlar fibers/epoxy composites increased by oxygen-plasma treatment. Plasma-treated Kevlar fiber shooed the maximum critical surface tension and polar term, whereas the untreated PBO fiber showed the minimum value. Microfibril fracture pattern of plasma-treated Kevlar fiber appeared obviously. Based on the propagation of microfibril failure toward core region. the number of AE events for plasma-treated PBO and Kevlar fibers increased significantly. The results oi nondestructive AE were consistent well with microfailure modes by optical observation in microdroplet and two-fiber composites tests.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2003.04a
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• pp.202-205
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• 2003

Investigated whether fiber orientation situation of fiber reinforcement macromolecule composition board and the fiber inclusion rate are perpendicular and horizontal direction tensile strength and some correlation. Fiber orientation situation of tensile strength of 0 direction of composition board increased changelessly by aeolotropy in isotropy. Tensile strength of 90 direction that is isotropy and tensile strength of 0 direction that is aeolotropy agreed almost. Get into aeolotropy, the reinforcement rate of fiber decreased. When load interacts for width direction of reinforcement.

• Proceedings of the Korean Fiber Society Conference
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• 2001.10a
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• pp.139-142
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• 2001

섬유강화 복합재료는 상대적으로 아주 높은 질량 대비 탄성계수를 가지고 있으므로 경량화 할 필요가 있는 물체나 관성력이 최소로 요구되는 부분에 사용되고 있다. 대부분의 복합재료판들은 고탄성-저신도 섬유를 사용하여 만든 단층의 복합재료를 그배향 방향을 조절하여 원하는 방향 특성으로 접근한다. 그러나 다층으로 만들어 2차원의 등방성 소재로 만들어 사용하고 있다. 그러나 이러한 경우에는 여러 층을 결합 하여야 하는 번거로움과 두께의 제약 등이 있다. (중략)

• Composites Research
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• v.15 no.4
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• pp.1-8
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• 2002

In this study, the rigidities of fiber-reinforced composite corrugated plates are derived to achieve the weight reduction, high strength, and high stiffness. The vibration of the corrugated plates for all the conventional boundary conditions in the plates is analyzed numerically by applying the derived rigidities, and so the analysis system is programmed to obtain the results by using Visual Basic language. Consequently, the characteristics of fiber-reinforced composite corrugated plates can be easily investigated from the results provided by the programmed system.

• Journal of the Korea Concrete Institute
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• v.23 no.4
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• pp.461-469
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• 2011

In this study, the effect of polyvinyl alcohol (PVA) fiber volume fraction on the pullout behavior of structural synthetic fiber in hybrid structural synthetic fiber and PVA fiber cement composites are presented. Pullout behavior of the hybrid fiber cement composites and structural synthetic fiber were determined by dog-bone bond tests. Test results found that the addition of PVA fiber can effectively enhance the structural synthetic fiber cement based composites pullout behavior, especially in fiber interface toughness. Pullout test results of the structural synthetic fiber showed the interface toughness between structural synthetic fiber and PVA fiber reinforced cement composites increases with the volume fraction of PVA fiber. The microstructural observation confirms the incorporation of PVA fiber can effectively enhance the interface toughness mechanism of structural synthetic fiber and PVA fiber reinforced cement composites.