• Proceedings of the Korean Society For Composite Materials Conference
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• 2001.10a
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• pp.74-78
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• 2001

In this study, out-of-plane properties and CTEs were predicted for 8-harness satin weave textile composites. The properties were calculated by unit cell analysis for configurations with varied waviness ratio and phase shifts. Macro elements were employed to reduce the computer resource requirement. It was found that the out-of-plane properties and CTEs were varied as the phase shift changed. However the dependency was much weaker than the in-plane properties.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2003.10a
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• pp.95-98
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• 2003

In woven or knitted preforms for composites, the yams are often twisted for avoiding damage due to the contact with the textile machine elements. When the preforms of twisted yams are used in carbon/carbon composites, the thermal conductivity of the composites varies depending upon the degree of the yarn twist. This paper presents a thermal conductivity model of spun yarn composites. The thermal-electrical analogy and the averaging technique have been adopted in this analysis. The model prediction has been correlated with experimental results in order to confirm the model predictability. Parametric study has also been conducted to examine the effect of the yam twist on the thermal conductivity of spun yarn composites.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2000.11a
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• pp.183-186
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• 2000

A new textile metal matrix composite fur electronic packaging was developed and characterized. The thermal management materials consist of a plain woven carbon fabric as reinforcement and pure aluminum as matrix. The finite element method has been utilized in the analysis of thermal stress between the constituent components of packaging. The prototype part was manufactured by the liquid pressurizing method. The composite has CTE values of 4 to $5{\times}10^{-6}\;^{\circ}C^{-1}$10 in the range of $25^{\circ}C$ ~ 175$^{\circ}C$, resulting in good agreement with electronic materials such as Si and GaAs.

• Structural Engineering and Mechanics
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• v.77 no.5
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• pp.651-659
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• 2021

In this study, a new constitutive model has been developed to predict the elastic behavior of plain weave textile composites, using the finite element (FE) method. The geometric conditions and basic assumptions of this model are based on the basics of a continuum theory developed for the plane curved composites. In this model, the mechanical properties of the weave region and pure matrix region is calculated separately and then imported for the FE analysis. This new constitutive model is used to implement the mechanical properties of weave region in the representative volume element (RVE). The constitutive relations are implemented as user-material subroutine code (UMAT) in ABAQUS® FE software. The results of FE analysis have been compared with experimental results and other data available in the literature. These comparisons confirmed the capability of the presented model for the prediction of effective elastic properties of plain weave fabric composites.

• Composites Research
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• v.28 no.3
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• pp.112-117
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• 2015

Mechanical properties of nonwoven alfa fiber based reinforced biocomposite were evaluated to assess the possibility of using it as a new material in engineering applications such as orthopedic application. Samples were fabricated by needle punching, thermal bonding and Hydroentanglement, by blending alfa fibers with wool fibers or Polypropylene fibers. The mechanical properties were tested and showed that the nonwoven NW3 (alfa fiber/PP/PLA, with hydroentanglement) is the best. It has a value of stress at break of 1.94 MPa, a strain of 54.2% and a young's module of 7.95 MPa, in a production normal direction. A biocomposite has been made with NW3 mixed with PMMA matrix. The use of nonwoven based alfa fiber in reinforcing the composite material increases its rigidity and the tensile strength; the elongation was found to be 1.53%, the Young's Module of 1.79 GPa and the tensile at break of 15.06 MPa. Results indicated that alfa fibres are of interest for low-cost engineering applications and can compete with glass fibres in orthopedic application.

• Advanced Composite Materials
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• v.17 no.3
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• pp.235-246
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• 2008

This paper is concerned with geotextiles bonded chemically with geogrid to form a geocomposite. Geotextiles, thermally bonded and non-woven, play an important role as a separator. Also, this study investigates the resistance to the application environment of geotextile composites. Here, numerous tests have been performed and it was revealed from experimental results that thermally bonded geotextile in geosynthetic composites showed superior characteristics to that manufactured from needle punched non-woven method in terms of tensile strength, tensile strain and high separation performance. It was noted from experiments that the geotextile prepared for separation purpose and manufactured in a thermal bonding method showed relatively low permittivity so that it could be used as a smooth separator. In addition, PVA geotextile/HDPE geomembrane composites were designed and manufactured to investigate the waste landfill related properties. Numerous experiments have been performed and experimental results were summarized to evaluate practical applicability of PVA geotextile/HDPE geomembrane composites. Among the properties of proposed geomembrane composites, evaluation has been focused on the investigation of mechanical properties, AOS (apparent opening size), permittivity and ultraviolet stability.

• Earthquakes and Structures
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• v.16 no.3
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• pp.369-373
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• 2019

Construction industry is one of the largest markets for composite materials. Composite materials are mostly utilized as surface coatings or concrete reinforcements, and they can hardly be found as a load bearing member in buildings. The three-dimensional composite structures with considerable bending, compressive and shear strengths are capable to be used as construction load bearing members. However, these composites cannot compete with other materials due to higher manufacturing costs. If the cost issue is resolved or their excellent performance is taken into consideration to overcome disadvantages related to economic-competitive challenges, these 3D composites can significantly reduce the construction time and result in lighter and safer buildings. Sandwich composite panels reinforced with 3D woven glass fabrics are amongst composites with highest bending strength. The current study investigates the possibility of utilizing these composite materials to construct ceilings and their application as slabs. One-to-one scale experimental loading of these composite panels shows a remarkable bending strength. Simulation results using ABAQUS software, also indicate that theoretical predictions of bending behavior of these panels are in good agreement with the observed experimental results.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.18 no.1
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• pp.59-64
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• 2019

In recent years, the HP-CRTM method, which has the ability to produce carbon fiber-reinforce plastic composites at high speeds, has come into the spotlight in the automotive parts industry, which demands high productivity. Multi-axial carbon fabric, an intermediate material used in this HP-CRTM molding process, consists of layered fibers without crimp, which makes it better in terms of tensile and shear strength than the original woven fabrics. The NCF (non-crimp fabric) can form the layers of the carbon fiber, which have different longitudinal and lateral directions, and ${\pm}{\theta}$ degrees, depending on the product's properties. In this research, preforms were made with carbon fibers of ${\pm}45^{\circ}$ and $0/90^{\circ}$, which were lamination structures under seven different conditions, in order to create the optimal laminated structure for automobile reinforcement center floor tunnels. Carbon fiber composites were created using each of the seven differently laminated preforms, and polyurethane was used as the base material. The specimens were manufactured in accordance with the ASTM D3039 standards, and the effect of the NCF lamination structure on the mechanical properties was confirmed by a tensile test.

• Textile Coloration and Finishing
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• v.21 no.4
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• pp.1-10
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• 2009

This paper surveys the physical properties of sheath/core nylon/PET high hollow composites filaments and its fabrics according to the various elution conditions such as concentration of elution, eluted time and eluted temperature. For this purpose, sheath/core nylon/PET filament was texturized and four kinds of fabric specimens were woven with different warp and weft densities. These grey fabrics were eluted with two kinds of concentrations of NaOH (30g/l, 40g/l), three kinds of eluted temperatures $50^{\circ}C,\;60^{\circ}C,\;85^{\circ}C$) and two kinds of eluted times (60min, l20min). The elution characteristics of these specimens were investigated and discussed with different elution conditions. In addition, the mechanical properties such as extensibility, bending rigidity, shear modulus and compressional work of these specimens aceording to the elution conditions were analysed and summarized with cross-sectional shapes of eluted filaments measured by SEM.

• Korean Journal of Materials Research
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• v.2 no.5
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• pp.366-374
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• 1992

Mechanical and impact properties of stitched S2 glass fiber reinforced polyester woven laminates composites have been studied. Laminates were stitched using Kevlar 49 thread with 1/2, 1, and 2 inch stitch spacing. Tensile and 3-point bending tests haute been performed to evaluate the mechanical properties of stitched and unstitched laminates. Impact tests at applied energy of 234.7J were performed to examine the impact behavior and toughness changes of the specimen. The same specimens were also tested repeatedly at low impact energy level of 110.2J for 3 times to evaluate damage tolerance properties. The tensile and 3-point bending test results showed that one inch spacing specimen had the highest tensile and flexural strength. It also showed the highest energy absorption capability and the best damage tolerance property at the repeated impact test. The half inch spacing specimen showed the lowest tensile strength and energy absorption property at the impact energy level of 234.7J, even though it had the highest frequency of stitching thread.