• Journal of the Korean Wood Science and Technology
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• v.23 no.2
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• pp.55-69
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• 1995

The primary objective of this research was to investigate optimum manufacturing condition of thin composite panels composed of sawdust, polyethylene film and polypropylene net. At the study the experiment was designed to make thin board in which sawdust offers effectiveness as core composing material, polyethylene as adhesive with added urea resin, and polypropylene as stiffness and flexibility in the composition panel. 100 types of thin composite panels were manufactured according to press-lam and mat-forming process of various hot pressing conditions(pressure, temperature and time). They were tested and compared with control boards on bending properties(MOR, MOE, SPL, WML), internal bond strength, thickness swelling, linear expansion and water absorption. At the same time the visual inspections of each types of panels were accomplished. The physical and mechanical properties of composite types passed by visual inspection were analyzed by Tukey's studentized range test. From the statistical analysis, the optimum manufacturing condition of thin composite panels were selected. Compared with two manufacturing processes, mat-forming process performed better than press-lam process in all tested properties. The optimum manufacturing conditions resulted from the experiment and statistical analysis were able to determine as following: the press temperature was shown the most good result at 130$^{\circ}C$ in mat forming process and 140$^{\circ}C$ press lam process, the press time 4 min in both processes, but the press pressure was 25-10kg/$cm^2$ in mat forming and 15k/$cm^2$ press lam process.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2005.11a
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• pp.45-48
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• 2005

In manufacturing process of composite cylinders with metal liner, the autofrettage process which induces compressive residual stress on liner to improve cycling life can be applied. In this study, finite element analysis technique is presented, which can predict accurately the compressive residual stress on liner induced by autofrettage and stress behavior after. Material and geometry non-linearity is considered in finite element analysis, and the Von-Mises stress of a liner is introduced as a key parameter that determines pressure cycling life of composite cylinders. Presented methodology is verified through fatigue test of liner material and pressure cycling test of composite cylinders.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.10 no.1
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• pp.47-53
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• 2011

From recent research, it has revealed that Electroacitve polymer(EAP) has a physical limitation. Carbon nanotube(CNT) is known as the promising material which has excellent electro-mechanical characteristics and is mostly defect-free. It is expected that a successful synthesis of CNT and Nafion known as a primary material for IPMC would make a great improvement on its electro-mechanic feature. In this paper, we suggest the method of synthesis of CNT with Nafion which improves electro-mechanical characteristic. Using mechanical dispersion with Nafion and Isopropyl Alcohol(IPA), we disperse Single-walled carbon nanotubes(SWCNT). For a uniformly layer of CNT, we used a spray gun on a hot plate by a simplified method. In the result, we fabricated a disperse SWCNT/Nafion composite uniformly.

• Journal of Aerospace System Engineering
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• v.10 no.3
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• pp.63-69
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• 2016

The properties of composite materials, when compared to those of metallic materials, are highly variable due to many factors including the batch-to-batch variability of raw materials, the prepreg manufacturing process, material handling, part-fabrication techniques, ply-stacking sequences, environmental conditions, and test procedures. It is therefore necessary to apply reliable statistical-analysis techniques to obtain the design allowables of composite materials. A new composite-material qualification process has been developed by the Advanced General Aviation Transport Experiments (AGATE) consortium to yield the lamina-design allowables of composite materials according to standardized coupon-level tests and statistical techniques; moreover, the generated allowables database can be shared among multiple users without a repeating of the full qualification procedure by each user. In 2005, NASA established the National Center for Advanced Materials Performance (NCAMP) with the purpose of refining and enhancing the AGATE process to a self-sustaining level to serve the entire aerospace industry. In this paper, the statistical techniques and procedures for the generation of the allowables of aerospace composite materials will be discussed with a focus on the pooling-across-environments method.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.19 no.2
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• pp.75-80
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• 2020

In this study, we designed car frames for collision analysis using carbon fiber reinforced polymer (CFRP) as the lighter composite material. The impact conditions were 100 percent frontal impact, 40 percent frontal impact, and 90 degrees side impact. The impact analysis measured the maximum stress at velocities of 20km/h and 40km/h for each condition and evaluated the vulnerable points in the car frame. Additional supports have been designed both to improve the weak points in existing vehicle frames, and to be taken into account when new parts are assembled. Our impact analysis compared the results of maximum stress on the car frame with and without the support.

• Textile Coloration and Finishing
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• v.35 no.1
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• pp.29-41
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• 2023

This study is about a hybrid lightweight cowl crossbeam structure with high rigidity and ability to absorb collision energy to support the cockpit module, which is an automobile interior part, and to absorb energy during a collision. It is a manufacturing process in which composite material bracket parts are inserted and injected into existing steel bars. When considering the mounting condition of a vehicle, the optimization of the fastening condition of the two parts and the mechanical properties of the composite material is acting as an important factor. Therefore, this study is about a composite material having a volume content of Polyamide(PA) and Glass Fiber used as a composite material for a composite material-metal hybrid cowl crossbeam. As a result of analyzing the physical properties of the PA/GF composite material, experimental data were obtained that can further enhance tensile strength and flexural strength by using PA66 rather than PA6 used as a base material for the composite material. And based on this, it contributed to securing the advantage of lightening by using high-stiffness composite material by improving the high disadvantage of the weight of the cowl crossbeam material, which was made only of existing metal materials.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.10 no.5
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• pp.131-136
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• 2011

Many researchers are recently studying about Electroactive polymer(EAP). But it has a physical limitation, because of property of material. Carbon nanotube(CNT) is known as the promising material which has excellent electro-mechanical characteristics and is mostly defect-free. It is expected that a successful synthesis of CNT and Nafion known as a primary material for IPMC would make a great improvement on its electro-mechanic feature. This study focuses on the method of synthesis of CNT with Nafion which improves electro-mechanical characteristic. To come up with mechanical dispersion with Nafion and Isopropyl Alcohol(IPA), we dispersed Single-walled carbon nanotubes(SWCNTs). For a uniformly layer of CNT, we used a spray gun on a hot plate by a simplified method. We fabricated a disperse SWCNT/Nafion composite uniformly. Through the use of the E-beam evaporator to form an uniform electrode layer, we consummated the IPMC actuator. This result shows improving 1.5 times mechanical properties about driving force in IPMC.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.20 no.12
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• pp.78-84
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• 2021

Reducing the weight of automobiles is a significant global developmental task. Two materials are used to lighten automobiles: aluminum and CFRP frames. Aluminum is a non-ferrous metal, and CFRP is a composite material. They are lighter and harder than other materials. The two materials were used for the collision analysis. Subsequently, the two cases were compared. Three cases were considered for the collision analysis: head-on collision, partial head-on collision, and side collision at a speed of 60 km/h. The three cases were compared and analyzed considering the materials used to understand the difference between aluminum and CFRP and their collision characteristics.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.23 no.1
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• pp.96-102
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• 2015

Composite materials are widely used as structural materials for manufacturing an aircraft, due to their : low weight, low thermal expansion coefficient, production efficiency, anisotropy, corrosion resistance and long fatigue life. The range of using composite materials has been extended from the fuselage and the wings to the entire aircraft structure. In this paper, by analyzing the problems which were generated while designing and fabricating aircraft structures using composite materials, the differences between metallic structures and composite structures are described. In addition, the methodological improvement directions on design and fabricating are described.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.15 no.5
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• pp.100-108
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• 2016

In various industries, many researches studies have been done in using nano thin film fabrication technology. In the field of printed electronics, various electronic devices can be fabricated using a direct printing process of on multiple functional materials. It has the advantages of low prices, environment-friendly environmentally friendly, flexibleility, large scale, mass production produced, simple process and so on. In this study, a viable thin film fabrication technology has beenwas introduced using the surface acoustic wave mechanism for thin film deposition. Fabrication of thin films using organic, inorganic and composite of organic/inorganic materials have been were analyzed through the experimental research. In this experiment, organic material MEH:PPV, inorganic material ZnO and composite material MEH:PPV/ZnO have been depo sited as thin films.