• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.37 no.3
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• pp.255-266
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• 2009

In this study, a robust aerospace system design process for the aerospace system is developed by considering the uncertainties of user requirements, manufacturing errors, and operational environment variation. User requirements are analyzed and quantified by decision making models and system engineering methods to select alternative concepts which satisfies the various requirements. Robust design and optimization method is applied to derive the robust solution of the selected system. First, a variance of objective function is calculated, and a mean value and a variance of target value are determined by the deterministic design optimization results of the system. A robust optimum design formulation is then needed to derive the robust solution that minimizes the variance of the response and moves the mean values to the target value. It is applied to Very Light Jet (VLJ) aircraft to which much attention is paid recently in civil aerospace market.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.20 no.7
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• pp.665-671
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• 2010

To improve the gear noise quality, gear tooth grinding machine are widely used in automotive industry. While using the gear profile grinding machine to improve the gear tooth quality of the transmission, several defects such as chattering, tooth waves that cause the gear noise occasionally happened. But it is very difficult to solve that problem, because there is no one who knows the setting up the optimal grinding condition appropriately. The abnormal manufacturing conditions which make the gear noise make the engineer to spend a lot of time, effort, and money. Due to demands for solving the serious abnormal gear noise happened in the automatic transmission in the mass product stage, the vibration checking process in the worm wheel axis, work rotation and fixed axis of the grinding machine were adapted to find the root causes. As a result, gear profile wave are affected by the work rotation axis's unbalance which is caused by worm wheel feeding speed. And a primary and the secondary grinding feeding speed, cutting oil, work fixed forces are also proved as the important factors. After setting up the grinding condition reported in this paper, it was adapted successfully to the grinding machine to manufacture the new automatic transmissions' gear. The gear noise was dramatically disappeared and the process and the results will offer good guides to the engineers who manufacture the gear with the grinding machine.

• Journal of Adhesion and Interface
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• v.1 no.1
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• pp.30-37
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• 2000

This study focused on the direct blending of bonding agents (resorcinol, hexamethylenetetramine, NaOH) into rubber compound to simplify the composite manufacturing process. The mechanism of direct blending system was studied by comparing the following two cases. The one is direct blending of bonding agents into rubber compound and then allows the reaction (Case I). The other is mixing of reactant obtained by reaction of bonding agents (Case II). According to the morphology analysis, the Case II showed the clean interfacial area between bonding agents and matrix rubber, while the Case I created the new interphase under proper processing condition. Also, the optimum adhesion strength between SBR and nylon cord could be obtained with bonding agents whose molar ratios of resprcinol/hexamethylenetetramine was 1.2/1 in the recipes.

• Journal of Engineering Education Research
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• v.24 no.5
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• pp.38-45
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• 2021

The CanSat was designed as an educational satellite simulation program that implements the overall system of the satellite such as the command processing unit, the communication unit, and the power unit in a structure of the size of a can. In particular, the training effect is very excellent because the trainee can learn a process similar to the actual satellite development process by designing, manufacturing, testing, and launching. Republic of Korea Air Force Academy has been using the CanSat production kit used by the domestic can satellite contest experience department for education, but since it was produced based on PCB, it was impossible to show creativity and operation was restricted even with small mistakes. In this paper, we analyze the existing CanSat kit and propose a new educational CanSat kit that can be used in creative engineering design and practice subjects that will be reorganized into a regular course from 2021, and a lesson plan. In conclusion, by using the proposed CanSat kit for lectures, it is possible to achieve educational purposes and effects, improve lecture satisfaction, and provide stable instruction.

• Composites Research
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• v.33 no.6
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• pp.383-389
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• 2020

Thermoplastic composite is introduced to design an automotive door impact beam, and the manufacturing process is demonstrated. The safety regulation for vehicles has been steadily tightened, and weight-reduction has become a mandatory factor in the automotive industry. Hence, both high-performance and lightweight are demanded for automotive components. The aim of the present study is to develop an automotive door impact beam using fiber-reinforced thermoplastic composites to reduce the weight of the impact beam while increasing its mechanical performance. A new production method which combines continuous fiber-reinforced composite and LFT(Long Fiber-reinforced Thermoplastic) is implemented by using insert injection molding process. The mechanical performance of the composite impact beam was evaluated using 3-point bending tests. Thermoplastic composite will expand its application range to various automotive components due to its light-weight design capability and high productivity.

• Journal of Digital Convergence
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• v.20 no.4
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• pp.597-606
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• 2022

This study attempted to find a new manufacturing method through Basalt fiber and resin infusion method to expand the range of expressions of Contemporary jewelry produced in studios. To this end, the concept of fiber introduction and infusion method was examined through analysis of used cases, and based on this, flat plates and color samples were produced, and then the samples were made to estimate the possibility of direct use in jewelry. As a result, the infusion method process presented certain results that could be used as a production process in the studio, and Basalt fibers were able to express various colors of spray and porselin, especially fiber its painted with porselin, which have high strength and they can be expressed intentionally, it are very valuable as jewelry's material, it is expected to be an opportunity to expand the practical production methods and expressions of Contemporary jewelry.

• Journal of the Semiconductor & Display Technology
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• v.21 no.1
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• pp.148-154
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• 2022

As the 4th industrial age approaches, the demand for semiconductors is increasing enough to be used in all electronic devices. At the same time, semiconductor technology is also developing day by day, leading to ultraprecision and low power consumption. Semiconductors that keep getting smaller generate heat because the energy density increases, and the generated heat changes the shape of the semiconductor package, so it is important to manage. The temperature change is not only self-heating of the semiconductor package, but also heat generated by external damage. If the package is deformed, it is necessary to manage it because functional problems and performance degradation such as damage occur. The package burn in test in the post-process of semiconductor production is a process that tests the durability and function of the package in a high-temperature environment, and heat dissipation performance can be evaluated. In this paper, we intend to review a new material formulation that can improve the performance of the adapter, which is one of the parts of the test socket used in the burn-in test. It was confirmed what characteristics the basic base showed when polyamide, a high-molecular material, and alumina, which had high thermal conductivity, were mixed for each magnification. In this study, functional evaluation was also carried out by injecting an adapter, a part of the test socket, at the same time as the specimen was manufactured. Verification of stiffness such as tensile strength and flexural strength by mixing ratio, performance evaluation such as thermal conductivity, and manufacturing of a dummy device also confirmed warpage. As a result, it was confirmed that the thermal stability was excellent. Through this study, it is thought that it can be used as basic data for the development of materials for burn-in sockets in the future.

• Journal of Powder Materials
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• v.29 no.4
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• pp.320-324
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• 2022

Lightweight steel is a crucial material that is being actively studied because of increased carbon emissions, tightening regulations regarding fuel efficiency, and the emergence of UAM, all of which have been recently labeled as global issues. Hence, new strategies concerning the thickness and size reduction of steel are required. In this study, we manufacture lightweight steel of the Fe-Mn-Al-C system, which has been recently studied using the DED process. By using 2.8 wt.% low-Mn lightweight steel, we attempt to solve the challenge of joining steel parts with a large amount of Mn. Among the various process variables, the laser scan power is set at 600 and 800 W, and the laser scan speed is fixed at 16.67 mm/s before the experiments. Several pores and cracks are observed under both conditions, and negligibly small pores of approximately 0.5 ㎛ are observed.

• Journal of the Korea Society of Computer and Information
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• v.14 no.9
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• pp.179-187
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• 2009

The national boundary's meanings turn to weak according to advent of Global enterprises. The place for design a product and marketing are separated to actual market. R&D is to the area where the knowledge activity is well, and low skilful product assembling is to the place the low wage is acceptable. It shows that the importance of net work structure. From early 90's, production system is diversified to markets where with the consumer as the central as multifarious items and creation new demands through consumer's participation into manufacturing process. This phenomenon show that logistics structures adapt to demand of technical variation, and the development of e-business with VAN(:value added network) and EDI(:Electronic data interchange) prove it. This study tried to analyze utilitarian assay about systems those land, sea, air logistics through documents research, and this study also present the direction of logistics system of airline company and goal of development on the based to the model of domestic airline company accordingly.

• Journal of Digital Convergence
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• v.10 no.9
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• pp.89-100
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• 2012

This study is designed to explore whether the integration of product development and quality management have influence on the success of localization of weapon system. To that end, empirical analysis has been conducted on a total of 110 systematic major defense contractors, their subcontractors and small-and-medium sized defense contractors. The result shows that success of the localization of weapons system, as well as the price of localization, manufacturing time, and quality turn out to have significantly influenced by factors of quality management capabilities including human resources development capability, organizational capability and process capability and R&D development factors including human resources capabilities, capability to accumulate technology and internal/external collaborative capabilities. To sum up, this study suggests that integration of quality management and product development continuously provides a competitive strength in developing new product by a non-defense company as well as localization of core parts of weapon system.