Most of automobile steering parts are manufactured through the multi-stage cold forging process using round-bar drawn materials. The same process is applied to the ball stud parts of the outer ball joint, and various research activities are being carried out to reduce the extreme manufacturing cost in order to survive in the limitless competition. In this paper, we present a quantitative prediction method for the limiting life of the die as a method for cost reduction in the multi-stage cold forging process. The load on the die was minimized by distributing the forming load based on process optimization through finite element analysis. In addition, based on the quantitative prediction algorithm of the limiting life of the die, the application of the split die and the optimization of the phosphate treatment of the material surface are presented as a conclusion as a method to improve the limiting life of the die.

본 논문에서는 1차원 오일러 보 요소(Euler-Bernoulli Beam Element)를 이용한 회전익기 축계에 대한 중량 최적설계를 수행하였다. 회전 축계의 특성을 고려해 비틀림(Torsion)과 베어링과 같은 축지지 강성 및 플랜지(Flange) 질량을 모두 고려하였고, 동적 안전성 확 보를 위해 고유치 해석을 수행하여 임계속도(Critical Speed)와 기어박스로부터 오는 치 변형 가진을 회피할 수 있도록 하였다. 축의 길 이는 고정된 상태에서 두께와 반경을 조절하여 중량 최적화를 수행하였으며, 최적화 과정은 2단계로 나누어 진행하였다. 1단계에서 는 비틀림 강도를 제약조건으로 하여 중량을 최적화한 후 2단계에서는 축계 안정성 확보 기준(Headquarters, U.S. Army Material Command, 1974)에 따라 축의 비틀림 강도에 대한 제약조건을 만족시키며, 축의 1차 모드가 임계속도를 회피할 수 있도록 축 1차모드 와 임계속도의 차이가 최대가 되도록 최적화를 진행하였다. 주어진 1차원 보 요소를 이용하여 최적설계를 한 결과를 3차원 유한요소 모델과 실제 제작된 축게의 시험결과와 비교하여 제안된 방법을 검증하였다.

This paper describes the design of H-infinity controller for robust control of a DC motor system. The suggested controller can ensure robustness against disturbance and model uncertainty by minimizing H-infinity norm of the transfer function from exogenous input to performance output and applying the small gain theorem. In particular, the controller was designed to reduce the effects of disturbance and model uncertainty simultaneously by formalizing these problems as a mixed sensitivity problem. The validity of the proposed controller was demonstrated by computer simulations and real experiments. Moreover, the effectiveness of the proposed controller was confirmed by comparing its performance with PI controller, which was tested under the same experimental condition as the H-infinity controller.

The aim of this study was to develop Jiangxi Nuo masks using 3D digital fashion design technology and suggest various ways to utilize traditional culture based on the characteristics of Nuo masks, a traditional Chinese artifact of intangible cultural significance. The researchers conducted a literature review to gather information about Nuo culture and masks that could represent Jiangxi. Features of the masks were analyzed and classified. The result are as follows. First, the symbolic characteristics of Jiangxi’s Nuo masks can be divided into those based on their origin and history, the user’s social status, and the notions of primitive beliefs of the chosen people, such as naturism and totemism. Second, Nuo masks’ splendid decorations convey meanings such as luck, the bixie, longevity, wealth, and peace in the family. Third, playfulness in mask-making is about dismantling the original form of the mask, re-creating it through application. Fourth, the masks express primitiveness mostly by conserving the wood’s original color or material. The initial masks carved to represent images of figures aptly deliver the primitive forms and images of Nuo culture. In this study, Nuo masks were developed and produced using the 3D digital technology CLO 3D by adopting the expressive characteristics and applying design methods such as asymmetricity, exaggeration, and modification. The results of this study demonstrate the possibility of creating diverse as well as economical designs through the reduction of production.

The purpose of this study was to develop a 3D mesh-type impact protection pad with excellent motion adaptability and functionality by applying 3D printing technology. The hexagonal 3D mesh, which constitutes the basic structure of the pad, comprises two types: small and large. The bridge connecting the basic units was designed as the I-type, V-type, IV-type, and VV-type. After evaluating the characteristics of the bridge, it was found that the V-type bridge had the highest flexibility and tensile elongation. The hip joint pad and knee pad were completed by combining the hexagonal 3D mesh structure with the optimal bridge design. The impact protection pad was printed using a fused deposition modeling-type 3D printer with a filament made of thermoplastic polyurethane material, and the protection pad’s performance was evaluated. When an impact force of approximately 6,500N was applied to the pad, the force attenuation percentage was 78%, and when an impact force of approximately 8,000N was applied, the force attenuation percentage was 75%. Through these results, it was confirmed that the 3D-printed impact protection pad with a hexagonal 3D mesh structure connected by a V-shaped bridge developed in this study can adapt to changes in the body surface according to movement and provides excellent impact protection performance.

The purpose of this study is to develop Korean clothing designs that can satisfy future consumer’s needs based on the elements extracted through the content analysis method in a study on the design elements expressed in traditional outfits in the 2010s. To this end, data analyzing Hanbok in wedding magazines were used, and after extracting design elements, research methods for empirical design development were used. After subclassifying the major design elements, factors with a steady increase in frequency and appearance rate were identified. Through this, five elements capable of aesthetic sampling were extracted by complex expression methods and expressed in a total of seven combinations. The types extracted from the design elements are items, silhouette, top shape, skirt shape, skirt length, mixed items with increasing frequency. In the element of color, the adjacent color harmony, which showed the highest frequency of color, and the white-blue harmony, which showed an increase among them, were extracted. When using materials, top and skirt have similar usage rates of the same and different materials, so both contents were extracted, and many patterns were arranged in the top and the whole, but these three were extracted because there were increasing cases where there were no patterns. In the case of decoration, embroidery, pintuck, sakdong, applique, lace, ribbon on the top, silver foil and print on the skirt were extracted. Through this study, it was possible to propose a future Korean costume design model.

The purpose of this study is to investigate historical and geographical environments in the development of the Naxi costumes of Chinese ethnic minorities and their characteristics—including religious cultures and totem worship—and to suggest the direction of fashion design toward the modernization of traditional costumes. The research methodology involved the collection of materials and investigatation into the history, culture, and characteristics of Naxi costumes; in particular, the “seven-star” sheepskin cape, one of the Naxi people’s important ethnic costumes as demonstrated by the women’s clothing that has been designed in reflection of this traditional costume. The results are as follows. First, Naxi costumes are found to have overall coherence and distinct locality when retained in the process of modernizing the traditional costume. The theme of this work is titled “By the Light of the Moon and the Stars,” which is expressed in contemporary fashion by the use of grey and dark red against a background of black, a color preferred by the Naxi people. Second, the Naxi people’s seven-star sheepskin cape is a symbol of women’s clothing with its characteristic patterns, shapes, and colors, and it is subject to creative modernization while retaining its unique ethnic characteristics. Third, the work expresses the contemporary stylishness of the costume while maintaining the customary decorative accessories from the Naxi people’s traditional culture.

This work provided a review of three techniques—(1) spectrochemical, (2) electrochemical, and (3) spectroelectrochemical– for molten salt medias. A spectroelectrochemical system was designed by utilizing this information. Here, we designed a spectroelectrochemical cell (SEC) and calibrated temperature controllers, and performed initial tests to explore the system’s capability limit. There were several issues and a redesign of the cell was accomplished. The modification of the design allowed us to assemble, align the system with the light sources, and successfully transferred the setup inside a controlled environment. A preliminary run was executed to obtain transmission and absorption background of NaCl-CaCl2 salt at 600°C. It shows that the quartz cuvette has high transmittance effects across all wavelengths and there were lower transmittance effects at the lower wavelength in the molten salt media. Despite a successful initial run, the quartz vessel was mated to the inner cavity of the SEC body. Moreover, there was shearing in the patch cord which resulted in damage to the fiber optic cable, deterioration of the SEC, corrosion in the connection of the cell body, and fiber optic damage. The next generation of the SEC should attach a high temperature fiber optic patch cords without introducing internal mechanical stress to the patch cord body. In addition, MACOR should be used as the cell body materials to prevent corrosion of the surface and avoid the mating issue and a use of an adapter from a manufacturer that combines the free beam to a fiber optic cable should be incorporated in the future design.

The design of a wooden impact limiter equipped to a transportation cask for radioactive materials was optimized. According to International Atomic Energy Agency Safety Standards, 9 m drop tests should be performed on the transportation cask to evaluate its structural integrity in a hypothetical accident condition. For impact resistance, the size of the impact limiter should be properly determined for the impact limiter to absorb the impact energy and reduce the impact force. Therefore, the design parameters of the impact limiter were optimized to obtain a feasible optimal design. The design feasibility criteria were investigated, and several objectives were defined to obtain various design solutions. Furthermore, a probabilistic approach was introduced considering the uncertainties included in an engineering system. The uncertainty of material properties was assumed to be a random variable, and the probabilistic feasibility, based on the stochastic approach, was evaluated using reliability. Monte Carlo simulation was used to calculate the reliability to ensure a proper safety margin under the influence of uncertainties. The proposed methodology can provide a useful approach for the preliminary design of the impact limiter prior to the detailed design stage.

디지털 정보 기술의 급속한 발전에 따라 사람들은 점점 더 자연스럽고 편리한 방식으로 인간과 컴퓨터의 상호작용을 실현하는 경향이 있습니다. 본고에서는 Leap Motion 센서를 하드웨어 플랫폼으로 하고 Unity3D 와 Leap Motion 플러그인을 소프트웨어 플랫폼으로 하여 가상 거문고의 상호작용 설계를 개발합니다. 또한 Leap Motion 장치의 개발과 연구를 통해 Leap Motion 센서에서 수집된 제스처 정보의 처리와 인식을 알고리 즘으로 구현하고, 제스처 인식 알고리즘을 이용하여 서로 다른 제스처를 분리하여 서로 다른 응답을 가능하 게 합니다.

최근 패션업계에서 이슈가 되고 있는 Virtual Fashion 관련 서비스는 소비자들이 피팅 서비스를 사용함에 있 어 실제 상황과 상호작용하는 것처럼 의류의 재질감, 색상 그리고 사이즈를 실제적으로 경험해 볼 수 있게 하는 수단으로 활용되고 있다. 하지만 기존에 생산한 3D Object 데이터에 대한 접근성 및 재활용성이 낮은 단점을 가지고 있다. 또한 다양한 데이터 포맷을 사용하면서 생성되는 Texture의 용량과 출력되는 Animation 파일들의 크기가 커서 최종 결과물의 용량이 비대 해지는 단점도 있다. 본 논문에서는 기존 선행 연구된 시 스템을 Legacy Virtual Fashion System으로 정의하고 해당 시스템에서 사용하던 자원들을 효율적으로 재활용 하고 프로세스 단축 및 Texture과 Animation의 용량을 축소시키기 위하여 공통으로 사용할 수 있는 게임 엔 진 기반의 Virtual Fashion 프레임워크를 제안하고 구현했다. 게임엔진 기반의 Virtual Fashion 프레임워크를 이용하여 Virtual Show Room, 3D Runway 및 Virtual Fashion Sample을 제작하고 또한 해당 프레임워크의 성능 을 측정하기 위하여 실험을 구성했다. 구성된 실험으로 최대 50%의 용량 감소의 효과를 확인했다. 또한 본 연구의 결과물을 이용하여 다양한 형태의 출력물을 개발 확대 적용하는 것 기대해 본다.

최근 게임상의 아이템을 현금화하여 게임 플레이를 통하여 본을 벌 수 있다는 개념의 P2E(Play to Earn)게임 들이 많이 생겨났다. 일부 저소득 국가에서는 일을 할 때보다 돈을 더 많이 벌게 되는 일이 벌어지면서 많 은 게임 기업들은 각자의 메인넷을 만들어서 각자의 생태계 안에서 게임을 서비스하고 있다. 초기에는 코딩 을 할 수 있어야만 NFT 발행이 가능했다. 하지만 코딩을 하지 않아도 되는 형태의 NFT 응용프로그램이 제 작되고 제작된 응용프로그램을 통하여 NFT 발행을 진행한다. 하지만 해당 응용프로그램들은 많은양의 그림 파일들을 다루기 때문에 한꺼번에 많은 발행 작업을 하면 컴퓨터 메모리 사용량이 지속적으로 늘어나는 단 점이 있다. 본 연구에서는 이러한 문제점을 해결하고자 새로운 NFT Game 프레임워크를 설계하고 구현하고 자 한다. 설계된 프레임워크는 기존의 문제점인 지속적으로 늘어나는 메모리를 정리하여 저사양 컴퓨터에서 도 원하는 만큼의 NFT를 발행 수 있게 지원하고자 한다. 또한 기능을 추가하여 자동으로 오픈마켓에 배포 할 수 있는 기능을 제공한다. 본 논문에서 제안하는 프레임워크는 3가지의 형태의 각 기능 역할을 하고있는 Market System 프레임워크, Game 프레임워크, NFT Conveter 프레임워크로 설계했다. C# 기반으로 제작하였으 며 게임엔진에 적용하기 위하여 Unity3D엔진으로 개발된 게임을 사용하였습니다. 프레임워크를 활용하여 아 이템 데이터를 NFT 토큰을 발행하여 마켓에 등록했다. 토큰의 Metadata에는 7가지의 의상 데이터 정보와 6 가지의 캐릭터 설정 정보 및 배경 화면을 등급을 나누고 분류하여 각각의 희소성을 부여했다. 본 연구의 결 과물로 Unity 기반의 게임들이 해당 프레임워크를 사용하여 다양한 형태로 NFT 발행을 확대 적용하는 것을 기대해 본다.

Equipment used for ships operating in the polar regions, such as icebreakers, should consider countermeasures against freezing. This study performed a structural design that prevents freezing and tolerates thermal stress and wind pressure of the air vent louver heating blades. As boundary conditions for performing the analysis, analysis was performed when the flow rates at the inlet end were 10m/s, 20m/s 30m/s, 40m/s, and 50m/s. As a result of the analysis, if the CNT heating element can maintain the heating performance of 200°C, the blade can maintain the room temperature state except for the end of about 40mm. There are pressure drop between the front and rear of the air vent louver. It can be seen that the allowable wind speed varies depending on the design criteria. As a results, it is required to select an optimal heating temperature to prevent condensation of a blade, optimize the generation of compressive stress by thermal expansion, and trade off the wind pressure and thermal stress according to wind speed.

The sub-frame is located on the lower body of a monocoque type vehicle and serves as an engine and suspension, and is an important object part that receives a lot of load. The existing press-type sub-frame has a large number of parts for assembling, which causes an increase in cost. Changing the machining form of this part from the existing press-type machining method to the hydro-forming machining method has the advantage of reducing the cost and weight at the same time due to the reduction of the process. Therefore, in this study, the purpose of this study is to change the design so that the sub-frame of the existing press type can be changed to the hydro-forming process method. To this end, we intend to present a design method by analyzing the effect on the rigidity of the sub-frame using the existing machining method through shape optimization analysis.

Bellows product is an important part in the area of plant engineering, shipbuilding and petrochemistry. For safety and durability it is necessary to consider lots of factors when designing it. This research developed a metal bellows design software based on EJMA 10th Edition manual. This Bellows software was developed by using Excel software and can be able to design U type of bellows which are Unreinforced Single Bellows, Unreinforced Double Bellows, Reinforced Single Bellows and Reinforced Double Bellows. The already proven bellows model were designed to verify this software. This software would predict the life cycle of a product and produce a company report to be provided to the demanding company. This suggested updated software will be helpful for design engineers to save time and effort.

본 연구에서는 3D 프린팅 FDM 방식의 적층 방향에 따라 기계적 물성이 달라지는 이방성 특성을 확인하고 이를 이용하여 위상 최 적설계를 수행하였다. 벤치마크 문제인 자동차 현가장치 부품 중 하나인 로어 컨트롤 암에 대하여 밀도법 기반 위상 최적설계를 수행 하였으며, 외부 하중과 이방성 특성에 따라 위상 최적결과가 다르게 나타나는 것을 확인하였다. 이를 이용하여 최적화된 모델에 대하 여 3D 프린터로 적층 방향을 달리하여 2가지 시험품을 제작하였으며 인장시험을 수행하였다. 시험시 3D 비접촉 변형률 측정기를 이 용하여 변형률을 구하였으며 이를 CAE 응답해석으로 얻은 변형률과 비교한 결과가 정량 및 정성적으로 일치하는 것을 확인하였다. 3D 프린팅 적층 방향을 고려한 위상 최적모델의 인장 실험 결과를 통해 해당 최적설계 방법론의 유효성을 검증하였다.