• 한국정밀공학회지
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• 제8권2호
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• pp.36-46
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• 1991

This study was carried out to investigate the characteristic of dynamic component in drilling. Materials used were carbon steel, brass and cast iron, and the drills used were high speed steel drill and cemented carbide. The cutting resistance generated in drilling was detected with the aid of piez0-electric tool dynamometer which has an excellent frequency response, and then the magnitude and shape of dynamic component and its frequency component as well were analyuzed. After a thorough study of interrelationship, the obtained results are as follows; 1) The shape of torque and thrust of the early drilling are different. 2) The shapes of dynamic component can be classified into four kinds. 3) Torque is related to frequency more closely than thrust. 4) As cutting speed increased, dynamic component increased. 5) Chipping took place continuously, and its size decreased as cutting proceeded.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 춘계학술대회논문집
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• pp.846-851
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• 2005

The purpose of this paper is that investigates the dynamic behavior characteristic of W.T.S(Wind turbine System) and carries out the evaluation analysis during operating W.T.S. To investigate the dynamic behavior characteristic of W.T.S, the experiments to measure vibration of the blade from the attached accelerometer on the flap and edge section of the blade that is one of the most important elements of dynamic characteristic of W.T.S are performed. Natural frequency and mode shape are calculated with commercial program (ANSYS) using the measured vibration acceleration that receives the signal with F.F.T Analyzer from the accelerometer. For validation of these experiments, the finite element analysis is performed with commercial F.E.M program (ANSYS) on the basis of the natural frequency and mode shape. The results indicate that experimental values have good agreements with the finite element analysis.

• 한국CDE학회논문집
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• 제6권2호
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• pp.89-100
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• 2001

Swept volume is the sweeping region of moving objects. It is used in various applications such as interference detection in assembly design, visualization of manipulator motions in robotics, simulation of the volume removal by a cutter in NC machining. The shape of swept volume is defined by the envelope, which is determined by the boundary of moving objects and its direction of motion. In order to implement the generation of swept volume, researchers have taken much effort to develop the techniques how to generate the envelope. However, their results are confined to envelope generated only in simple shape objects, such as polyhedra or quadric surfaces. This study provided the envelope generation algorithm of NURBS objects. Characteristic points were obtained by applying the geometric conditions of envelope to NURBS equations, and then characteristic curves were created by means of interpolating those points. Silhouette edges were determined in the following procedures. First, two adjacent surfaces which have the same edge were found from B-Rep data. Then, by taking the scalar product of velocity vector of a point on that edge with each normal vector on two surfaces, silhouette edges were discriminated. Finally, envelope was generated along moving direction in the form of ruled surfaces by using both the partial information between initial and final position of objects affecting envelope along with characteristic curves and silhouette edge. Since this developed algorithm can be applied not only to NURBS objects but also to their Boolean objects, it can be used effectively in various applications.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 추계학술대회 논문집
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• pp.222-228
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• 2007

In order to solve the problem of traffic holdups and environmental pollution(contamination), several metropolises are operating the subway and many local government plans hereafter the light rail vehicle operation and it is in the process of preparing. This point of time, it need to evaluate the comfortable characteristic of the seat which is closely connected with passenger and it should be reflected to the product design through the data analysis. The methods of the comfortable characteristic evaluation should be considered to various methods from physical factor to psychological factor. Among these, the most universal and possible quantitative measurement estimate through 'Body pressure measurement system'. From this paper, it was measured the body pressure of the subway seat which is in the process of operating in a domestic and it will be compared and analyzed the material & seat shape, so we evaluated the comfortable characteristic of the short-distance transportation railway vehicle. It was operated the man and woman who belongs in standard shape of Korean, we compared and analyzed the Peak position where the body pressure is visible and body pressure spread out.

• 한국소음진동공학회논문집
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• 제15권11호
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• pp.1232-1240
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• 2005

The purpose of this paper is that investigates the dynamic behavior characteristic of W.T.S (wind turbine system) and carries out the evaluation analysis during operating W.T.S. To investigate the dynamic behavior characteristic of W.T.S, the experiments to measure vibration of the blade from the attached accelerometer on the flap and edge section of the blade that is one of the most important elements of dynamic characteristic of W.T.S are performed. Natural frequency and mode shape are calculated with commercial program ( ANSYS) using the measured vibration acceleration that receives the signal with F.F.T Analyzer from the accelerometer For validation of these experiments, the finite element analysis is performed with commercial F.E.M program (ANSYS) on the basis of the natural frequency and mode shape. The results indicate that experimental values have good agreements with the finite element analysis.

• 한국전자통신학회논문지
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• 제16권2호
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• pp.227-232
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• 2021

본 논문에서는 다이폴 형태인 기존의 부분방전 센서의 특성을 개선하고자 센서 부분을 사다리꼴 형태로 변형시킴으로써 기존의 부분방전(PD: Partial Discharge) 센서의 단점인 협대역 특성을 개선하였다. 또한 외부부착 센서용으로 사용함에 따라 외부로 부터의 전자파 신호를 원천적으로 차단시킬 수 있는 구조인 캐버티(Cavity) 구조를 적용함으로써 저자세와 설치의 편리성을 갖는 구조적인 장점을 살리는 부분방전 센서를 제안하고자 한다. 실험 결과 중심주파수 2.45GHz에서 약 70.5%의 광대역(1.59~3.32GHz) 특성이 있음을 보여, 광대역 특성을 확인할 수 있었다.

• 한국지진공학회논문집
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• 제27권3호
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• pp.139-145
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• 2023

It is essential to determine a proper earthquake time history as a seismic load in a seismic design for a critical structure. In the code, a seismic load should satisfy a design response spectrum and include the characteristic of a target fault. The characteristic of a fault can be represented by a definition of a type of possible earthquake time history shape that occurred in a target fault. In this paper, the pseudo-basis function is proposed to be used to construct a specific type of earthquake, including the characteristic of a target fault. The pseudo-basis function is derived from analyzing the earthquake time history of specific fault harmonic wavelet transform. To show the feasibility of this method, the proposed method was applied to the faults causing the Gyeong-Ju ML5.8 and Pohang ML5.3 earthquakes.

• 한국주거학회논문집
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• 제21권5호
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• pp.23-33
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• 2010

In the late twentieth century, the multistory housing has become the most preferred housing type. Moreover, in multistory housing design, not only interior design but also exterior design, uniqueness and characteristic have been added as significant factors in design to break simplicity and uniformity. The purpose of this study is to understand the tendency of the elevation design in Europe and to suggest the idea for elevation design for domestic. Also, each elements of elevation were analyzed through classification and schematization which categorized by its own characteristic. Design elements can be classified into three categories. They are corresponding with inner spaces, emphasizing visual expression of exterior material and texture, and presenting aesthetic factors of building shape. Those are named as the Spatial Externalization, the Visual Expression, and the Expression of Building Shape. In this frame nineteen elevations of sixteen different cases were analysed. As a result of case studies, it is clear that elevation designs were not standardized and each cases has its own characteristics. Also it showed how the each design elements can be coordinated as a total design and how they expressed identities of each housing. This study could contribute to motivate diversifying the design of multistory housing.

• 한국강구조학회 논문집
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• 제13권5호
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• pp.587-597
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• 2001

연속체 쉘을 이산화한 구조시스템은 돔형 구조물을 만들기 위해 많이 이용되고 있으며, 이러한 구조물은 하중레벨이 어느 임계값에 도달하면 구조물의 형상에 따라 뜀좌굴(snap-through) 또는 분기좌굴(bifurcation)에 의한 불안정 현상이 일어난다. 케이블 돔의 구조거동 특성은 초기장력 및 외력에 다라 비선형성이 강하게 나타나며 또한 초기조건에 매우 민감하게 반응한다. 본 연구에서는 케이블 돔의 불안정 문제를 파악하기 위해 Geiger 모델을 대상으로 하여 초기 장력도입에 의한 형상결정 문제를 다루고 이를 이용하여 완전형상 및 초기형상 불완전을 도입하여 외력에 의한 불안전성현상을 규명한다.

• 한국해양공학회지
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• 제9권1호
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• pp.101-110
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• 1995

In SMA(Shape Memory Alloy), the degradation by fatigue is one of the most important problems to be overcome, when SMA is used for robot-actuator materials. The actuator is operated repetitively for long time and its repeating operation develops the fatigue degradation of SMA. The fatigue degradation changes the transformation temperature and deformation behavior and results in inaccurate operation and deformation which results form repeating operation is to be investigated in advance and the scheme to resolve those problems have to be made for the design of actuator. In this paper, for the improvement of the fatigue degradation by repetive movement and better control of the correct movement by the stability of martensite transformation in the development of Robots actuator, Pre-strain(0, 1.5, 5, 8%) are loaded in the specimens and fatigue testing were carried out by the method of heating and cooling in direct condition. From the results of these experiments, the effect on pre-strain which affect the transformation characteristic and fatigue degradation phenomena were correctly investigated.