• Composites Research
• /
• 제22권1호
• /
• pp.15-21
• /
• 2009

본 논문에서는 편향각을 갖는 직물 복합재료 시편을 제작하여 정적 압축실험과 피로실험을 수행하고 그 결과를 비교하였다. 직물구조의 차이에 따른 압축거동을 평가하기 위해 동일한 섬유와 기지로 구성된 일방향 복합재료와 평직 복합재료의 적층순서를 동일하게 조절한 시편을 준비하였다. 정적 압축실험을 통해 편향각을 갖는 시편의 강성과 강도를 측정하였고, 측정된 강도를 바탕으로 압축강도 예측식을 제안하였다. 피로실험을 통해 복합재료의 직물 구조의 차이에 의한 피로수명의 변화를 관찰하였으며, 편향각의 변화와 하중조건에 따른 피로수명의 차이를 비교하였다.

• 한국복합재료학회:학술대회논문집
• /
• 한국복합재료학회 2001년도 추계학술발표대회 논문집
• /
• pp.64-69
• /
• 2001

In general, laminate effective orthotropic thermal conductivities are dependent on fiber and matrix material properties, fiber volume fraction and fabric geometric parameters. This paper deals with the predicting method of the transverse and the in-plane thermal conductivities of plain weave fabric composites based on the three dimensional series-parallel thermal resistance network. Thermal resistance network was applied to unit cell model that characterizes the periodically repeated pattern of plain weave. Also, an experiment apparatus is setup to measure the thermal conductivities of composite material. The numerical and experimental results of carbon/epoxy plain weave are compared.

• 한국복합재료학회:학술대회논문집
• /
• 한국복합재료학회 2005년도 춘계학술발표대회 논문집
• /
• pp.125-129
• /
• 2005

A micromechanical model for predicting the elastic constants of stitched multi-axial warp knitted (MWK) composite is developed. The averaging method is used to obtain effective properties of stitched MWK fabric composites. In the analysis, a representative volume of the MWK fabric composite is identified. The geometric limitations, effects of stitching yarns and design parameters of MWK fabric composites are considered in the model. Then, the elastic properties of stitched MWK fabric composites are predicted. Finally, the predicted elastic constants are validated by comparison with experimental data. The predicted results are in fair agreement with the experimental results.

• 한국복합재료학회:학술대회논문집
• /
• 한국복합재료학회 2004년도 추계학술발표대회 논문집
• /
• pp.198-202
• /
• 2004

An analytical model using expanded bridging model was proposed to predict the elastic properties and behaviors of stitched multi-axial warp knitted (MWK) fabric composites, The characteristics of MWK fabric composites are the assemblage of multi-layers of fiber bundles for in-plane reinforcement and stitch yams for the through-the-thickness reinforcement. In the analysis, a representative volume of the MWK fabric composite was identified, The geometric limitations, effects of stitching yams and design parameters of MWK fabric composites were considered in the model. Then, the elastic properties and behaviors of MWK fabric composites were predicted, Finally, the results of proposed model of the composites were verified through the experiments, The predicted results were in fair agreement with the experimental results

• 한국염색가공학회지
• /
• 제16권5호
• /
• pp.42-47
• /
• 2004

The main objective of this work is to develop melt-blown nonwoven fabric composite materials have electromagnetic shielding characteristics using thin copper film. Melt-blown nonwoven fabric is the matrix phase and thin copper films are the reinforcement of the composite materials. Thin copper films are incorporated as conductive fillers to provide the electromagnetic shielding property of the melt-blown nonwoven fabric. The width and interval of thin copper films in the nonwoven fabric are varied by changing 1, 3, 5 mm for thin copper film's width and 1, 3, 5 mm for thin copper film's interval. The shielding effectiveness(SE) of various melt-blown nonwoven fabrics is measured in the frequency range of 50 MHz to 1.8 GHz. The variations of SE of melt-blown nonwoven fabric with width and interval of thin copper films are described. Suitability of melt-blown nonwoven fabric for electromagnetic shielding applications is discussed. The results indicate that the melt-blown nonwoven fabric composite material using thin copper film can be used for the purpose of electromagnetic shielding.

• 한국복합재료학회:학술대회논문집
• /
• 한국복합재료학회 2002년도 춘계학술발표대회 논문집
• /
• pp.89-92
• /
• 2002

Traditionally unidirectional laminated composite which are characterized by high specific stiffness and strength were used for structural application. But theses composites are highly susceptible to impact damage because of lower transverse tensile strength. The main failure modes of laminated composite are fiber breakage, matrix cracking and delamination for low velocity impact. The modified failure criterions are implemented to predict these failure modes with finite element analysis. Failure behavior of the woven fabric laminated composite which is used in forehead part of subway to lighten weigh has been studied. The new failure criterions are in good agreement with experimental results and can predict the failure behavior of the woven fabric composite plate subjected to low velocity impact more accurately.

• 대한기계학회논문집A
• /
• 제27권8호
• /
• pp.1338-1346
• /
• 2003

Three-dimensional formability of the thermoplastic laminar composite was studied according to manufacturing conditions. Five different types of the plain weave fabric were used as reinforcement with PET matrix. The square blank was made by press consolidation technique and formed in the type hemisphere. B-factor defined as the ratio of width of yarn and distance between yarns was used as the factor of formability in the type of plain weave fabric. The formability of PET/Glass fabric laminar composite was estimated in terms of forming rate and B-factor with the thickness distribution, area ratio of blank, and intra-ply shear angle. The thickness distribution across hemisphere was strongly affected by the B-factor, forming rate and blank thickness. The area ratio of blank was increased with B-factor, forming rate and blank thickness. Also, it was found that the intra-ply shear angle depends on the B-factor and forming rate.

• 한국의류학회지
• /
• 제23권4호
• /
• pp.584-592
• /
• 1999

Highly conductive polyaniline(PAn)-nylon 6 composite fabric was prepared by immersing the nylon 6 fabric in 0.5M aniline+0.35M HCl aqueous solution at 4$0^{\circ}C$ for 2hours, Polymerization was then followed by mixing the prepared oxidant and dopant solution(0.5M(NH4)2S2O+0.35M HCl) to the diffusion bath at 5$^{\circ}C$ for 30 minutes. The conductivity of prepared PAn-nylon 6 composite fabrics reached as high as 0.5$\times$10-1S/cm. Their conductivity were significantly affected by the aniline and oxidant concentration. As compared to those of nylon 6 fabric heat of fusion melting point the degree of crystallinity and tensile strength of PAn-nylon 6 did not significantly changed by inclusion of PAn. In the aspect of serviceability wheras the fabric conductivity was significantly decreased after multiple washion no significant changes in the fabric conductivity were observed after abrading the composite fabric over 50 cycles. However we found that the fabric conductivity could be recovered by acid re-doping with HCl.

• 한국복합재료학회:학술대회논문집
• /
• 한국복합재료학회 2002년도 추계학술발표대회 논문집
• /
• pp.79-82
• /
• 2002

A finite element method based on the two-dimensional progressive failure analysis considering material nonlinearity is presented for characterizing the strength and failure of the unidirectional-fabric hybrid laminated composite joints under pin loading. The 8-node laminated shell element is incorporated in the updated Lagrangian formulation. Failure criteria including the Maximum Stress and Tsai-Wu are used in conjunction with the complete unloading stiffness degradation method. For the verification, joint tests are conducted for the specimens with two different ply-number ratios of UD composite to fabric composite. Although there are some differences depending on ply-number ratios, the finite element model using the maximum stress criterion considering nonlinear material behavior predicts the failure strength best.

• 한국복합재료학회:학술대회논문집
• /
• 한국복합재료학회 2004년도 추계학술발표대회 논문집
• /
• pp.135-138
• /
• 2004

Because the compressive properties such as compressive stiffness and compressive maximum strength of the fabric composite materials are essential to analyse the drape behaviour and estimate the quality of the final products, compressive tests of fabric composites with different stacking sequences were performed. Appropriate shape and dimensions for the compressive test specimens were prepared and several specimens with different conditions were tested and compared with each other.