• 한국전산유체공학회:학술대회논문집
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• 2010.05a
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• pp.468-472
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• 2010

To develop the Exhaust Maniverter(Manifold and converter) it needs to consider flow characteristics related to durability and performance of the catalyst, manufacturability, etc. This paper presents the analysis results regarding to flow characteristics such as flow uniformity, tangential speed, O2 sensor sensitivity and CHT (conjugate heat transfer) for the LCF(Low Cycle Fatigue) for gasoline 2.0 liter engine. The results are satisfactorily corresponded to the general criteria. Also skin temperature and pressure drop wire measured at the Engine Bench. These results can be useful for the design guide for Exhaust Maniverter.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1999.10a
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• pp.579-584
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• 1999

The purpose of the present paper are not to develope machine tools of new concepts and advanced mechanisms but to introduce and apply new methods and concepts in the design procedure by using and changing the previously existing technologies. In this paper 3D modeller was proposed for designing machine tools and the design and the better manufacturability checking than 2D one so that design error was dramatically reduced. As designer may easily understand the real shape of a part and assembly object, it's easy to draw the drawings not only in a conceptual design but also in a detailed design. Also, design automation software enabled designer to consider the real important design parameters by reducing time to spend in estimating and calculating the strength of the model by the computer aided automatic calculation instead of a tedious and complex calculation by manual method and help him to easily make the decision for selecting the stocks and design the structure of part or unit of machine tools.

• Journal of Power Electronics
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• v.9 no.2
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• pp.243-258
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• 2009

Bearingless centrifugal pump systems are employed in the semiconductor, pharmaceutical and medical industries due to their facility for pumping high purity fluids without particle contamination. Two types of forces have to be generated by the stator units, namely bearing forces for achieving magnetic levitation, and drive forces for producing the needed pump torque. The generation of these forces requires bearing and drive windings, which can be realized as separate bearing and drive coils or as identical, combined coils on the stator claws. In this paper, a detailed comparison between these two winding concepts is undertaken, whereby the copper losses, the power electronics losses, and the achievable pump output pressure are evaluated for both concepts. For each criterion a ratio of improvement is calculated analytically which allows evaluation of the performance of the two winding concepts for any given pump operating point and design. Finally, also practical features such as control complexity, cabling effort and manufacturability are discussed and measurements on prototype systems are carried out to validate the considerations.

• Journal of Korea Society of Industrial Information Systems
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• v.3 no.1
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• pp.67-77
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• 1998

Reliability growth testing used to evaluate reliability in the automobile industry have not always been able to correctly address reliability concerns with increased confidence. The demand to confirm to all product performance requirements under various operating environments has added to the complexity of accurately assessin theproduct's reliability in the required development time. In addition, it is often desired to determine the relationship of a product's reliability to cost, development time, design, manufacturability and assembly. This paper presents the methods for reliability growth modeling to evaluate and interpret reliability concerns to support the reliability analysis of automobile assemblies and systems. This reliability growth modeling process is a mechanism to help "build in" reliability during early phases in the vehicle devleopment stage.

• Transactions of Materials Processing
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• v.26 no.5
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• pp.277-285
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• 2017

Vehicle weight reduction is a known strategy to improve fuel efficiency and strengthen exhaust gas regulation. The use of high strength steel can satisfy safety, efficiency, emission, manufacturability, durability, and cost requirements. However, springback of high strength steel results in undesired shape defects. Springback is one of the most important issues of high strength steel for many applications in an automobile. Servo press has various capabilities to improve defects, process conditions, and productivity problems when forming a high strength steel. Especially, servo press can be set to function with variable slide motion in a single operation. In this study, the effect of servo press slide motion on 980MPa high strength steel was investigated through U-bending test.

• Journal of Aerospace System Engineering
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• v.8 no.1
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• pp.12-17
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• 2014

In this paper, optimal design of composite rotor blade cross-section to consider manufacturability was performed. Skin thickness, torsion box thickness and skin lay-up angle were adopted as discrete design variables and The position and width of a torsion box were considered as continuous variables. An object function of optimal design is to minimize the mass of a rotor blade, and various constraints such as failure index, center mass, shear center, natural frequency and blade minimum mass per unit length were adopted. Finally, design variables such as the thickness and lay-up angles of a skin, and the thickness, position and width of a torsion box were determined by using an in-house program developed for the optimal design of rotor blade cross-section.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.21 no.47
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• pp.289-302
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• 1998

Concurrent Engineering(CE) can provide a competitive edge for companies that have confronted with rapidly changing market requirements, such as shortening of product life cycles, high quality, low cost, diversity of customer demand, and so on. We construct a prototype of integrated information system to support a new product development process by CE concept. This integrated information system can be useful for considering concurrently all of the aspect in the product design process. In this system, an Engineering Database is constructed for gathering data of four departments; i.e. marketing, production, quality control and design department. Also DFM(Design For Manufacturability) is applied for analysis of product design.

• Proceedings of the Korea Society for Simulation Conference
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• 1998.10a
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• pp.204-208
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• 1998

The fundamental issues to evaluate machine tool's performance through simulation pertain to the physical models of the machine tool itself and of process while the practical problems are related to the development of the modular software structure. It allows the composition of arbitrary machine/process models along with the development of programs to evaluate each state of machining process. Surface roughness is one of the fundamental factors to evaluate machining process and performance of machine tool, but it is not easy to evaluate surface roughness due to its tribological complexity. This paper presents an algorithm to calculate surface roughness considering cutting geometry, cutting parameters, and contact dynamics of cutting between tool and workpiece as well as tool wear in turning process. The designed virtual machining system can be used to evaluate the surface integrity of a turned surface during the design and process planning phase for the design for manufacturability analysis of the concurrent engineering.

• Journal of the Korea Society for Simulation
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• v.8 no.1
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• pp.19-33
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• 1999

The fundamental issues to evaluate machine tools performance through simulation pertain to the physical models of the machine tool itself and of process while the practical problems are related to the development of the modular software structure. It allows the composition of arbitrary machine/process models along with the development of programs to evaluate each state of machining process. Surface roughness is one of the fundamental factors to evaluate machining process and performance of machine tool, but it is not easy to evaluate surface roughness due to its tribological complexity. This paper presents an algorithm to calculate surface roughness considering cutting geometry, cutting parameters, and contact dynamics of cutting between tool and workpiece as well as tool wear in turning process. This proposed algorithm could be used in the designed virtual machining system. The system can be used to evaluate the surface integrity of a turned surface during the design and process planning phase for the design for manufacturability analysis of the concurrent engineering.

• Proceedings of the KIPE Conference
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• 2005.07a
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• pp.651-654
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• 2005

In this paper, an efficient switching pattern to equalize the size of transformer is proposed for a multi-level inverter employing cascaded transformers. It is based on the prior selected harmonic elimination PWM(SHEPWM) method. Because the maximum magnetic flux imposed on each transformer becomes exactly equal each to each, all transformers can be designed with the same size regardless of their position. Therefore, identical full-bridge inverter units can be utilized, thus improving modularity and manufacturability. The fundamental idea of the proposed switching pattern is illustrated and the analyzed theoretically. The validity of the proposed switching strategy is verified by experimental results.