• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 추계학술대회
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• pp.1151-1156
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• 2003

The dynamic properties of short-fiber reinforced Chloroprene rubber for vibration isolators have been studied as functions of interphase conditions and fiber content. The loss factor showed the maximum at strain amplitude 2%, and increased 0.09 for matrix, 0.05 for reinforced rubber with increasing frequency respectively. The dynamic ratio rapidly decreased with increasing strain amplitude, and some increased with increasing frequency. The better interphase condition showed the lower dynamic ratio. Therefore, the short-fiber reinforced rubber could have the better isolation in frequency ratio(${\sqrt{2}}min$.) compared to frequency ratio(${\sqrt{2}}max$.). And we have investigate the possibility of applying short-fiber reinforced rubber to automotive engine mount.

• Journal of Mechanical Science and Technology
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• 제16권2호
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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.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 1998년도 추계학술대회 논문집
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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.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 춘계학술대회논문집A
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• pp.85-90
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• 2000

The fracture toughness and crack propagation behaviors of short nylon66 fiber reinforced Chloroprene rubber nave been Investigated as functions of fiber aspect ratio, fiber content and interphase conditions. The J for crack initiation and rupture were determined for short-fiber reinforced rubber. The values of $J_c$ for most reinforced rubbers were low compared that of matrix. But, $J_r$ at rupture showed a higher value than that of matrix. The crack propagation behaviors were analyzed into 3 patterns with increasing fiber aspect ratio and fiber content. The tearing mechanisms of matrix and fiber reinforced rubber were observed by CCD camera focused on the tip of crack and load-displacement graph. Both cases showed a completely different behaviors

• 한국농공학회:학술대회논문집
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• 한국농공학회 2000년도 학술발표회 발표논문집
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• pp.451-457
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• 2000

A series of consolidated undrained triaxial tests for compacted short fiber reinforced clay were performed to increase the field applications, e.g. retaining wall, waste landfill, soft ground etc. of soil admixtures mixed with short fiber. Kaolin clay and three types of fiber were selected. To acquire reliable length of fibers, an auto cutter was used and a helical mixer was also used to avoid floating of fibers during mixing soil and fibers. It is found that reinforcing effect by aspect ratio and mixing ratio of short fiber decreases as confining pressure is increased. Reinforcing effect has a maximum value at the aspect ratio of 120 and the fiber content of 0.6%∼1.2% and low confining pressure like 50kPa.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2001년도 추계학술발표대회 논문집
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• pp.61-63
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• 2001

Residual stress distribution in injection-molded short fiber composites was determined using layer-removal method. Polysterene with 3 vol% carbon fibers was injection-molded into the tensile specimen. With milling machine layer-removal process was conducted and the curvature data were acquired. Treuting and Read analysis which is assuming isotropic material, and White analysis considering anisotropy due to the fiber orientation were used to calculate residual stress of the flow direction through the thickness direction and compared with each other.

• 대한기계학회논문집A
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• 제29권2호
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• pp.318-324
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• 2005

Theoretical efforts are performed to extend the formulation of NSLT(New Shear Lag Theory) for the prediction of the elastic modulus in short fiber composite. The formulation is based on the elastic stress transfer considering the stress concentration effects influenced by elastic modulus ratio between fiber and matrix. The composite modulus, thus far, is calculated by changing the fiber aspect ratio and volume fraction. It is found that the comparison with FEA(Finite Element Analysis) results gives a good agreement with the present theory (NSLT). It is also found that the NSLT is more accurate than the SLT(Shear Lag Theory) in short fiber regime when compared by FEA results. However, The modulus predicted by NSLT becomes similar values that of SLT when the fiber aspect ratio increases. Finally, It is shown that the present model has the capability to predict the composite modulus correctly in elastic regime.

• Composites Research
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• 제13권3호
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• pp.30-37
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• 2000

계면상 조건과 단섬유 함유량 증가에 따른 강화고무의 동적 특성에 대해 실험적 고찰을 하였다. 손실계수는 대체적으로 섬유 함유량 증가에 따라 감소하였고 계면상 조건에 따라 다른 경향을 보였다. 계면 조건이 우수할수록 손실탄성율, $E_2$ 는 낮게 나타났다. 또한 동배율은 섬유 함유량 증가에 따라 감소하였고, 계면상 조건이 우수할수록 크게 감소하였다. 따라서 단섬유 강화고무는 진동수비가 $\sqrt{2}$이상에서 더 큰 진동절연 효과가 있다고 할 수 있다. 손실계수와 동배률의 관계로부터, 자동차의 엔진과 차체의 진동을 절연하는 부품인 Engine Mount Rubber의 적용가능성을 검토하였다.

• Steel and Composite Structures
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• 제47권6호
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• pp.679-691
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• 2023

The application of short, fiber-reinforced polymer composite pipes has been increasing rapidly. A comprehensive review of the prior research reveals that the majority of the previously-reported studies have been conducted on the filament-wound composite pipes, and fewer studies have been reported on the mechanical behavior of short, randomly-oriented fiber composite pipes. On this basis, the main objective of this research endeavor is to investigate the mechanical behavior and failure modes of short, randomly-oriented glass-fiber composite pipes under three-point bending tests. To this end, an experimental study is performed in order to explore the load-bearing capacity, failure mechanism, and deformation performance of such pipes. Fourteen properly-instrumented composite pipe specimens with different diameters, thicknesses, lengths, and nominal pressures have been tested and also simulated using the finite element approach for verification purposes. This study demonstrates the effectiveness of the diameter-to-thickness ratio, length-to-diameter ratio, and nominal pressure on the mechanical behavior and deformation performance of short, randomly-oriented glass-fiber composite pipes.

• Composites Research
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• 제20권6호
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• pp.28-33
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• 2007

단섬유 강화고무의 관통 특성에 대해 섬유 종횡비(AR: 섬유 길이/섬유 직경), 섬유 함유량, 시편 크기 그리고 시험속도를 변수로 하여 연구하였다. 기지와 단섬유 강화고무의 관통 저항은 시편 크기의 증가에 따라 감소하였고, 동일한 시편 크기에서 시험 속도의 증가에 따라 관통 저항력은 증가하였다. 각각의 섬유 함유량에서 섬유 종횡비가 클수록 높은 관통응력 값을 보였다. 인장강도와 관통응력의 비교를 통해 시편 형상의 문제점에 대해 고찰하였다. 기지와 단섬유 강화고무의 막에 작용하는 힘은 시편의 크기에 관계없이 유사한 값을 보였고, 동일한 시편 크기에서 시험속도의 증가에 따라 증가하였다. 각각의 섬유함유량에서 섬유 종횡비가 클수록 막에 작용하는 힘은 크게 나타났다 전체적으로 시편 크기, 시험속도가 단섬유 강화고무의 관통 특성에 지대한 영향을 미침을 확인하였다.