• 대한조선학회논문집
• /
• 제35권4호
• /
• pp.98-108
• /
• 1998

중앙 단면도 등의 선박의 초기 구조설계는 여러 가지 이유로 2차원으로 설계되어 다른 설계부서에 도면으로 전달되고 있다. 본 연구에서는 기능이 서로 다른 여러 가지 컴퓨터 시스템사이의 데이터 교환을 위한 예제로, AutoCAD로 작성된 2차원의 초기 구조 설계 데이터를 구조해석(FEM) 시스템이나 상세설계 시스템(AutoDef)등의 다른 시스템에서 사용할 수 있는 데이터를 생성해 보았다. 이를 위해 STEP 제품모델의 방법에 따라 데이터가 정의 되었으며 2D 형상이나 3D 와이어프레임, 솔리드 모델등 다양한 형상을 다룰 수 있는 복합다양체 모델링 형상 도구인 ACIS가 사용되었다.

• Journal of Advanced Marine Engineering and Technology
• /
• 제22권6호
• /
• pp.836-843
• /
• 1998

In this paper effects of resonator within intake manifold system on volumetric efficiency were investigated n the 4-cylinder and 4 stroke Diesel Engines. The effects of resonator system were analyzed on resonant speed and on volumetric efficiency for a complicated intake system with resonator was confirmed. And the optimum design method of the resonant system which had the overall high and flat characteristic of volumetric efficiecncy was proposed.

• International Journal of Automotive Technology
• /
• 제8권5호
• /
• pp.575-581
• /
• 2007

As current and future automobile emission regulations become more stringent, the research on flow distribution for an exhaust manifold and close-coupled catalyst(CCC) has become an interesting and remarkable subjects. The design of a CCC and exhaust manifold is a formidable task due to the complexity of the flow distribution caused by the pulsating flows from piston motion and engine combustion. Transient flow at the exhaust manifold can be analyzed with various computational fluid dynamics(CFD) tools. However, the results of such simulations must be verified with appropriate experimental data from real engine operating condition. In this study, an experimental approach was performed to investigate the flow distribution of exhaust gases for conventional cast types and stainless steel bending types of a four-cylinder engine. The pressure distribution of each exhaust sub-component was measured using a simulated dynamic flow bench and five-hole pitot probe. Moreover, using the results of the pitot tube measurement at the exit of the CCC, the flow distribution for two types of manifolds(cast type and bending type) was compared in terms of flow uniformity. Based on these experimental techniques, this study can be highly applicable to the design and optimization of exhaust for the better use of catalytic converters to meet the PZEV emission regulation.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 1998년도 춘계학술대회논문집; 용평리조트 타워콘도, 21-22 May 1998
• /
• pp.166-172
• /
• 1998

In contrast to the conventional intake manifold of steel or aluminum material, the lst natural frequency range of plastic intake manifold becomes very lower to ca. 40Hz. That causes negative effects on the engine control unit installed inside the throttle body. In this paper, support design concepts to increase the natural frequency range larger than max. 200Hz are suggested based on the vibration analysis results using finite-element method. In conclusion, it is shown that the vibration level can be reduced most effectively by the installation of the neck support bracket between the throttle body and the plenum chamber.

• 동력기계공학회지
• /
• 제14권4호
• /
• pp.37-42
• /
• 2010

This paper deals with the sealing mechanism of the gasket component and the effects of design parameters for the exhaust manifold. The finite element model includes hot-end exhaust system and a simplified gasket model supplied by ABAQUS software. The mechanical behaviors of bead and body of a gasket are measured after several times of cyclic loads by gasket supplier. From the finite element analysis due to the cyclic thermal loads, the flange of exhaust manifold shows thermal expansion and contraction in longitudinal direction as well as convex and concave deformations with respect to the engine cylinder head. And, the contact pressures of the gasket beads suddenly changes by normal deformation of inlet flanges. Therefore, the magnitudes of contact pressures could be used to determine the sealing characteristics of the exhaust gas in the exhaust system. The distributions of contact pressures in gasket bead lines shows a good agreement with the engine test results.

• Journal of Mechanical Science and Technology
• /
• 제20권3호
• /
• pp.391-398
• /
• 2006

This work involves a method for modeling the flow distribution in the stack of a solid oxide fuel cell. Towards this end, a three dimensional modeling of the flow through a Solid Oxide Fuel Cell (SOFC) stack was carried out using the CFD analysis. This paper examines the efficacy of using cold flow analysis to describe the flow through a SOFC stack. It brings out the relative importance of temperature effect and the mass transfer effect on the SOFC manifold design. Another feature of this study is to utilize statistical tools to ascertain the extent of uniform flow through a stack. The results showed that the cold flow analysis of flow through SOFC might not lead to correct manifold designs. The results of the numerical calculations also indicated that the mass transfer across membrane was essential to correctly describe the cathode flow, while only temperature effects were sufficient to describe the anode flow in a SOFC.

• 한국산학기술학회논문지
• /
• 제8권5호
• /
• pp.984-990
• /
• 2007

본 연구에서는 자동차용 배기관에 대하여 유동, 열변형 및 내구해석 등 유동과 구조의 연계 해석을 수행하여, 배기관의 $O_2$ 농도의 유동분포, 고온의 배기가스에 의한 열적 거동 및 그 내구성능을 평가함으로써, 자동차 배기관의 최적설계를 위한 가이드로 활용하고자 한다.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 2003년도 ICCAS
• /
• pp.180-185
• /
• 2003

In order to enhance dexterity in execution of robot tasks, a redundant number of degrees-of-freedom (DOF) is adopted for design of robotic mechanisms like robot arms and multi-fingered robot hands. Associated with such redundancy in the number of DOFs relative to the number of physical variables necessary and sufficient for description of a given task, an extra performance index is introduced for controlling such a redundant robot in order to avoid arising of an ill-posed problem of inverse kinematics from the task space to the joint space. This paper shows that such an ill-posedness of DOF redundancy can be resolved in a natural way by using a novel concept named “stability on a manifold”. To show this, two illustrative robot tasks 1) robotic handwriting and 2) control of an object posture via rolling contact by a multi-DOF finger are analyzed in details.

• 한국공작기계학회논문집
• /
• 제17권6호
• /
• pp.97-103
• /
• 2008

In this paper, the Post Process for the manifold complex processing using CAD/CAM Software of two and a half Dimensions(2.5D) has been developed to maximize the application of the manifold manufacturing machine. Many companies are currently making use of high price systems to improve manufacturing process using the multi-axial complex manufacturing machine. In accordance with the requirements, the utilization of CAD/CAM Software for the manifold complex manufacturing machine is earnestly demanded. However, the experts who have experience in manifold manufacturing machine are insufficient. Consequently the outcomes of the Post Process for 2.5D CAD/CAM Systems have been dealt in order to be smoothly operated by those who have basic skills and be understood in process drawings. CNC program functions can be specially used as they are, when drawn up. The Post Process for the original point designation and transformation of coordinates has been developed and applied. The results gave proof of practical manufacturing outcomes.

• 한국정밀공학회지
• /
• 제26권12호
• /
• pp.102-109
• /
• 2009

This study proposes the structural optimization of a manifold valve. FE analysis is performed to evaluate the strength of a manifold valve. In addition, the structural optimization technique is applied to reduce its weight. In this study, the optimization method using the kriging interpolation method is adopted to obtain the minimum weight satisfying the strength constraint. The maximum stress and the weight are replaced by the metamodels. In this process, tile sample points are generated by latin-hypercube design. Optimum designs are obtained by ANSYS Workbench and the in-house program.