• 한국자동차공학회논문집
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• 제3권6호
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• pp.96-111
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• 1995

A bellows is a component installed in the automobile exhaust system to reduce the impact from an engine. It's stiffness has a great influence on the natural frequency of the system. Therefore, it must be designed to keep the specified stiffness that requires in the system. This study present the finite element analysis of U-typed bellows using a curved conical frustum element and the shape optimal design with specified stiffness. The finite element analysis is verified by comparing with the experimental results. In the shape optimal design, the weight is considered as the cost function. The specified stiffness from the system design is transformed to equality constraints. The formulation has inequality constraints imposed on the fatigue limit, the natural frequencies, the buckling load and the manufacturing conditions. A procedure for shape optimization adopts a thickness, a corrugation radius, and a length of annular plate as optimal design variables. The external loading conditions include the axial and lateral loads with a boundary condition fixed at an end of the bellows. The recursive quadratic programming algorithm is selected to solve the problem. The result are compared with the existing bellows, and the characteristics of the bellows is investigated through the optimal design process. The optimized shape of the bellows are expected to give quite a good guideline to the practical design.

• Journal of Welding and Joining
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• 제17권3호
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• pp.71-78
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• 1999

The welded metal bellows is commonly manufactured by welding pairs of washer-shaped discs of thin sheet metal stamped from strip stock in thickness from 0.025 to 0.254 mm. The discs, or diaphragms, are formed with mating circumferential corrugations. In this study, the diaphragms were welded by using a CW Nd: YAG laser to form metal bellows. The bellows was fixed on a jig and compressed axially, while Cu-rings were installed between belows edges for intimate contact of edges. The difference between the inner diameter of bellows and jig shaft causes an eccentricity, while the tolerance between motor shaft and jig shaft causes a wobble type motion. A vision sensor which is based on the optical triangulation was used for seam tracking. An image processing algorithm which can distinguish the image by bellows edge from that by Cu-ring was developed. The geometric relationship which describes the eccentricity and wobble type motion was modeled. The seam tracking using the image processing algorithm and the geometric modeling was performed successfully.

• 한국정밀공학회지
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• 제16권3호통권96호
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• pp.30-37
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• 1999

This paper represents the development of the brake system for the inline skate using bellows. The inline skate that is used at present has defects due to frequent impulse, which weakens the breaking force by damaging the parts. Therefore to solve these problems a break system for the inline skates using hydraulics is suggested. To solve the oil leakage problems, bellows is used. Also to prevent the breaks from not touching the ground when skating the bellows is placed at the heel, high as possible. To obtain fast response speed, the ratio of inner diameter of the bellows is changed so that with only a small displacement from the bellows the rubber pad attached to the bellows will touch the ground fast. The performance of the break system using bellows depends on the optimal design of the bellows. Therefore the parameters that changes the form of the bellows are tested and also the interaction between the forces are investigated. The performance of new model brake system with bellows and old model system with only a rubber pad without bellows was estimated through observation of braking posture.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 추계학술대회논문집
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• pp.306-309
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• 2005

This parer describes the tracking control simulation of 6-DOF shaking table with a bell crank structure, which converts the direction of reciprocating movements. For the Joint coordinate-based control which uses lengths of each actuator, the trajectory conversion process inverse kinematics is performed. Applying the Newton-Euler approach, the dynamic equation of the shaking table is derived. To cope with nonlinear problems, time-delay control(TDC) is considered, which has been noted for its exceptional robustness to parameter uncertainties and disturbance, in addition to steady-state accuracy and computational efficiency. If the nominal model is equal to the real system, joint coordinate-based control can be very efficient. However, manufacturing tolerances installation errors and link offsets contaminate the nominal values of the kinematic parameters used in the kinematic model of the shaking table. To compensate differences between the nominal model and the real system. the joint coordinate-based control using acceleration feedback in the Cartesian coordinate space is proposed.

• 대한건축학회논문집:계획계
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• 제35권12호
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• pp.93-104
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• 2019

This study set out to analyze the architectural trends in Bell's works and spaces by applying the Gaze theory of Jacques Lacan to his minimalism works, concept changes in their changing process, and the development of exhibition spaces related to him. The findings were as follows: first, his early glass cube works sought after the reproduction of the Real Order through the repeating eyes of viewers and objects by using exhibition lighting; second, his works in the Standing Wall category pursued the reproduction of the Real Order through the repeating eyes of many different viewers around objects; third, his Nesting Boxes tried to reproduce the Real Order of a higher competition level in the perception aspects, making the repetitive elements of Standing Walls converge and including even external environmental elements; fourth, there is no decisive gaze sought after by Judd or the Key Signifiant as the core of Lacan's philosophy in Bell's formative works; and finally, Bell's works pursue the completion of Simulacrum through the infinite repetition of Derrida's Deconstruction Philosophy through the infinite visual repetition sought after by Gehry and Moss in the LA School of Architects who shared the same area and period with him.

• 한국수소및신에너지학회논문집
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• 제35권1호
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• pp.75-82
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• 2024

In this study, design parameter exploration based on finite element analysis was performed to find the optimal shape of bellows, the key component of compressor-embedded refueling tank for a newly developed hydrogen refueling station capable of high-pressure charging above 900 bar. In the design parametric study, the design variables took into account the bellows shapes such as contour radius and span spacing, and the response factors were set to the maximum stress and the gap in the contact direction. In the shape design of the compressor bellows for hydrogen refueling station considered in this study, it was found that adjusting the contour span is an appropriate design method to improve the compression performance and structural safety. From the selection of optimal design, the maximum stress was reduced to 49% compared to the initial design without exceeding the material yield stress.

• 콘크리트학회논문집
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• 제18권6호
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• pp.769-776
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• 2006

최근 급속한 산업의 발달과 더불어 토목 건축기술의 발달로 콘크리트 구조물의 초고층화 대형화가 이루어 지고 있으며, 이러한 대형 구조물의 시공에 있어서 콘크리트의 온도상승은 부재의 내 외부 온도차이로 인한 온도응력에 의하여 균열을 발생시켜 구조물의 내하력 및 내구성에 심각한 손상을 가져올 수 있다. 연구에서는 시멘트 및 혼화재의 종류 및 배합설계 조건에 따라 콘크리트의 수화발열 특성 및 콘크리트의 공학적 특성에 대해 실험을 진행하였다. 시멘트 종류는 1종 보통포틀랜드시멘트, 혼합시멘트인 고로슬래그시멘트 및 4종 포틀랜드시멘트(벨라이트시멘트)를 사용하였으며, 혼화재 종류로는 플라이애쉬와 고로슬래그미분말을 사용하였다. 혼화재의 사용방법은 일반적으로 사용되는 플라이애쉬 25% 대체한 경우와 비교용으로 고로슬래그미분말을 50% 대체한 경우(2성분계 배합)와 또는 플라이애쉬와 혼합 사용(3성분계 배합) 방법을 적용하였다. 본 연구 결과, 결합재 종류 및 설계 조건에 따른 수화발열특성에 있어서는 벨라이트시멘트를 사용하는 것이 가장 효과적이며, 플라이애쉬를 사용한 경우도 수화열 저감 효과는 우수한 것으로 나타났으며, 수화발열특성을 비롯한, 콘크리트의 품질 특성을 종합적으로 고려할 경우, 고로슬래그미분말의 사용이 효과적이며, 특히 고로슬래그미분말과 플라이애쉬를 혼합사용한 3성분계의 배합설계가 가장 효과적인 것으로 판단된다.

• 한국컴퓨터정보학회논문지
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• 제13권7호
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• pp.291-305
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• 2008

모바일 기술의 진화는 전통적인 음악 산업의 보완과 새로운 음악시장의 확대는 물론이고 음악시장에 새로운 패러다임을 만들어 가고 있는 등 음악 산업에 막대한 영향을 미치고 있다 그러나 현재까지의 모바일 음악콘텐츠에 관한 연구는 모바일 콘텐츠 전반에 대한 분석에 치중되어 있어서 실질적으로 모바일 음악콘텐츠 상품을 개발하고, 서비스를 제공하는 기업들에게 유익한 자료를 제공해 주기 어려웠다. 따라서 본 연구는 음악콘텐츠를 생산, 유통, 판매하는 기업의 입장에서 소비자들의 어떤 요인이 모바일 음악콘텐츠 상품의 지속적 사용에 영향을 미칠지에 대하여 연구 및 분석하였다. 모바일 음악콘텐츠 지속적 사용에 영향을 미치는 요인에 대한 구체적인 분석을 하기 위해 모바일 음악콘텐츠를 벨소리 콘텐츠, 통화연결음 콘텐츠, 음악전곡다운로드 콘텐츠 3가지 유형으로 분류하고, 각 유형별로 지속적 사용에 영향을 미치는 요인을 분석하였다. 연구결과는 첫째, 벨소리콘텐츠의 경우 이용경력, 차별성, 편재성이 인지된 용이성에 영향을 미치고 신뢰성, 보안성, 맞춤성이 인지된 유용성에 영향을 미치며, 인지된 용이성은 인지된 유용성과 지속적 사용에 영향을 미치며, 인지된 유용성은 지속적 사용에 영향을 미치는 것으로 나타났다. 둘째, 통화연결은 콘텐츠의 경우는 인지된 용이성이 지속적 사용에 영향을 미치지 않는 것을 제외하고는 벨소리콘텐츠의 결과와 동일하게 나타났다. 셋째, 음악전곡 다운로드의 경우 이용경력, 복제가능성, 신뢰성이 인지된 용이성에 영향을 미치고, 이용경력 맞춤성이 인지된 유용성에 영향을 미치며, 인지된 용이성과 인지된 유용성이 지속적 사용에 영향을 미치는 것으로 나타났다.

• 과학과기술
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• 제31권3호통권346호
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• pp.77-79
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• 1998

오늘날의 성인들은 어린 시절 공룡은 냉혈 동물이며 자기 몸의 온도를 자동조절할 수 없고 몸을 데우는데 오로지 태양에만 기댔다고 배웠다. 그러나 쥬라기공원에 등장하는 포악한 벨로시랩터는 입김을 씌워서 창을 흐리게 만드는데 이것은 어떤 조건에서도 몸 속의 체온을 자동조절할수 있는 온혈 동물의 능력을 보여주는 것이다. 공룡은 과연 냉혈동물이었는가 아니면 온혈동물이었는가하는 문제는 마침내 고생물학자들을 양 진영으로 갈라놓았다.

• 한국세라믹학회지
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• 제36권6호
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• pp.599-603
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• 1999

In an effort to improve the mechanical properties of the belite cement active belite cement clinker was synthesized. Properties of the clinker were characterized by a XRD, FT-IE optical microscopy and SEM. The additive effects of slag on the hydration properties were investigated by the measurement of compressive strength heat evolution and SEM. The experimental results exhibited that the 3wt% borax was effective in stabilizing $\alpha$'-C2S and the addition of 5wt% anhydrite and 40wt% slag wee effective in the hydration.