• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2002.04a
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• pp.649-654
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• 2002

In recent days the more use of CFRP composite is in the airplane, automobile, and sport goods , etc., the more necessity of research on it in this engineering. In this research, the CFRP composite specimen are fabricated by 48 CFRP plies with 8 orientation angles, and the specimens are drilled with 3 tools. The results are analyzed with consideration of cutting force, type of tools and fabrication condition. The specimens with each drilling conditions are also investigated with SEM. The optimal drilling conditions such as drill types and cutting fence with respect to the fabricating condition are studied.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.05a
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• pp.960-963
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• 2002

In recent days the more use of CFRP composite is in the airplane, automobile, and sport goods, etc., the more necessity of research on it in this engineering. In this research, the CFRP composite specimen are fabricated by 48 CFRP plies with 8 orientation angles, and the specimens are drilled with 3 tools. The results are analyzed with consideration of cutting force, type of tools and fabrication condition. The specimens with each drilling conditions are also investigated with SEM. The optimal drilling conditions such as drill types and cutting force with respect to the fabricating condition are studied.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.12 no.6
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• pp.8-13
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• 2003

CFRP composite has a lot of merits such as mechanical characteristic, light weight and thermal resistance. For these merits CFRP is applied to so many industrial area. In order for the composite materials to be used in the aircraft structures or machine elements, accurate surfaces for bearing mounting or joints must be provided, which require precise machining. In this paper, the relationship between the stack thickness and drill diameter is examined from the drilling experiment, which is the drilling of 16, 32, 48p1ies specimen with the ${\phi}8$, ${\phi}10$, ${\phi}12mm$ cemented carbide drill. The results are analyzed with consideration of cutting force, stack thickness and drill diameter.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2003.04a
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• pp.190-195
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• 2003

CFRP composite has a lot of merits such as mechanical characteristic, light weight, and thermal resistance. For these merits CFRP is applied to so many industrial area. In this paper, the relationship between the stack thickness and drill diameter is examined from the drilling experiment, which is the drilling of 16, 32, 48 plies specimen with the $\phi$8, $\phi$10, $\phi$12mm cemented carbide drill. The results are analyzed with consideration of cutting force, stack thickness and drill diameter.

• The Journal of the Acoustical Society of Korea
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• v.13 no.6
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• pp.50-59
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• 1994

Spectral analysis of transient elastic waves were carried out in order to identify the propagation modes in glass and unidirectional carbon fibre reinforced plastic (CFRP) plates. Pencil leads were broken on the surface of plates to generate elastic waves, and two broad band transducers of 6.35 mm in diameter and 10 MHz center frequency were placed at the linear location from the source. The frequency spectra of detected signals showed that the wave propagation in the plates obeyed the Lamb wave dispersion relation. The transient signals were the fast propagating modes around maximum group velocity of the lowest and first order symmetric $modes(S_{0} and S_{1}),$ and first order antisymmetric $mode(A_{1})$. The transient signals were not severely distorted due to relatively small dispersion of those modes around the maximum group velocity. The fastest propagating mode in the plates was shown to be $S_{0}$ mode less the than cut-off frequency of $A_{1}$ mode.

• Journal of Aerospace System Engineering
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• v.12 no.6
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• pp.58-65
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• 2018

The dynamic characteristics of the deployable composite parabolic reflector with several panels were numerically and experimentally investigated. The deployment mechanism is designed to efficiently fit in a small volume. The parameters guiding the deployment are determined by considering; the number of panels, folding/twisting angles, and the driving forces of actuating devices. The panels are fabricated using carbon fiber reinforced plastics (CFRPs). The zero-gravity simulator is manufactured for the unfolding test. The deployment behaviors of the reflector are finally observed.

• Composites Research
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• v.35 no.2
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• pp.115-119
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• 2022

The performance of carbon fiber is important for the production of these high-quality polymer composite materials such as CFRP (Carbon Fiber Reinforced Plastic). For this purpose, it is essential to use an optimized spinning process for improving the mechanical, physical, and structural properties of the precursor fiber, which greatly affects the properties of the carbon fiber, and the use of a suitable precursor polymer. In this study, the content of MAA (Methacrylic Acid), MAA injection time, and concentration of AIBN (2,2'-Azobis(2-methylpropionitrile)) were set as parameters for the polymer synthesis process, and Poly(AN-co-MAA) (poly(acrylonitrile-co-methacrylic acid)) was polymerized by solution polymerization. Poly(AN-co-MAA) with a molecular weight of 305,138 g/mol and an MAA ratio of 4.2% was dissolved in DMF (N,N-dimethylformamide) at a concentration of 16.0 wt%, and then a precursor fiber was prepared through dry-jet-wet spinning. The precursor fiber had a tensile strength of ~1.06 GPa and a tensile modulus of ~22.01 GPa, and no voids and structural defects were observed on the fiber.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.7 no.11
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• pp.925-932
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• 2017

In this study, the analysis of plate under torsion was carried out according to stacking angle at the unidirectional carbon fiber reinforced plastic(UD CFRP) among composite materials. In case of UD CFRP, the material property due to stacking angle becomes different. Also, the stacking angles were designated to 15°, 30°, 45°, 60°, 75° and 90° at the study models. The notch hole was applied at the center part by supposing that rivet or hole was used. The analysis method was used by applying the experimental method at ISO 15310. Two jigs were fixed at the lower part and two jigs were descending at the upper part. As seen by the analysis result values at this study, the shear stress happening at the fracture part was seen with the lowest value in case of the stacking angle of 45°. It is known that the case of the stacking angle of 45°has the structural safety and durability higher than those of the other stacking angles when the torsion applies. It is thought that this result can be applied to the data of basis which can be devoted to the durability when the torsion is applied at CFRP plate.

• Composites Research
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• v.37 no.3
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• pp.170-178
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• 2024

This study proposes a hybrid composite where a thin copper film (Cu film) is embedded in carbon fiber reinforced plastic (CFRP), and quantum annealing is applied to derive the combination of Cu film placement that maximizes the through-thickness thermal conductivity. The correlation between each ply of CFRP and the Cu film is analyzed through finite element analysis, and based on the results, a combination optimization problem is formulated. A formalization process is conducted to embed the defined problem into quantum annealing, resulting in the formulation of objective functions and constraints regarding the quantity of Cu films that can be inserted into each ply of CFRP. The formulated equations are programmed using Ocean SDK (Software Development Kit) and Leap to be embedded into D-Wave quantum annealer. Through the quantum annealing process, the optimal arrangement of Cu films that satisfies the maximum through-thickness thermal conductivity is determined. The resulting arrangements exhibit simpler patterns as the quantity of insertable Cu films decreases, while more intricate arrangements are observed as the quantity increases. The optimal combinations generated according to the quantity of Cu film placement illustrate the inherent thermal conductivity pathways in the thickness direction, indicating that the transverse placement freedom of the Cu film can significantly affect the results of through-thickness thermal conductivity.

• Transactions of the Korean Society of Automotive Engineers
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• v.25 no.1
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• pp.1-10
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• 2017

In reverse engineering, one of the main tasks is reconstructing the mechanical properties of used materials. For an isotropic material, it could be defined by a single tensile test using a coupon extracted from the structure. In contrast, CFRP composites require many tests and complex procedures to define all the material properties because CFRP is an orthotropic material and a stacked laminate. In this paper, the procedure to reconstruct composite material properties is studied by using the classical lamination theory and the test data of three different laminates from a composite structure. A sample reconstruction of composite material properties using a composite car body is introduced to verify the method.