• Journal of the Korean Society for Precision Engineering
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• v.26 no.4
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• pp.120-127
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• 2009

Spindle units of machine tool are very important part in the manufacturing area. Recently high speed machining has become the main issue of metal cutting. To develop high speed machine tools, a lot of studies have been carried out for high speed spindle. Due to increase of the rotational speed of the spindle, there has been renewal of interest in vibration of spindle. This paper concerns the improvement of spindle design using design of experiments. To improve the design of critical speed and weight of spindle, the experiments using central composite method have been carried out. The targets are critical speed and weight of spindle. For optimization of critical speed and weight and optimization of only critical speed by operation of all area search through response optimizer, the result of analysis has improved design of each factor. Finite element analyses are performed by using the commercial codes ARMD, CATIA V5 and ANSYS workbench. From the results, it has been shown that the proposed method is effective for modification of spindle design to improve critical speed and weight.

• Korean Journal of Computational Design and Engineering
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• v.8 no.4
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• pp.222-230
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• 2003

Artificial intelligence has been used in the configuration design stage of high-speed train. The traction system of a high-speed train is composed of transformers, motor blocks, and traction motors of which locations and number in the trainset should be determined in the early stage of the train conceptual design. Components of the traction system are heavy parts in the train, so it gives strong influence to the top speeds and overall train configuration of high-speed trains. Top speeds have been predicted using the neural network with the associated data of the traction system. The neural networks have been learned with data sets of many commercially operated high-speed trains, and the predicted results have been compared with the actual values. The configuration design of the train set of a high-speed train determines the basic specification of the train and layout of the traction system. The neural networks is a useful design tool when there is not sufficient data for the configuration design and we need to use the existing data of other train for the prediction of trainset in development.

• Transportation Technology and Policy
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• v.6 no.1
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• pp.155-170
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• 2009

In an effort to increase the operational efficiency of highways, South Korea has been increasing its design speed recently. However, the use of higher design speed will also increase construction costs. Moreover, increasing the design speed is expected to have an impact on safety. Hence, there is a strong need to demonstrate that the benefits outweigh the cost of having a higher design speed. This study surveyed a sample of design engineers to determine their awareness of the consequences of increasing design speed and their assessment of the right design speed for an actual rural arterial. In addition to the survey, a case study of three recently upgraded highways was conducted to determine the changes in traffic volumes, speeds, travel times, and safety.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2005.10a
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• pp.156-163
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• 2005

This study was attempted to provide some fundamental data for safety structrural design of biological production facility. Wind load and snow load, acting on agricultural structures is working more sensitive than any other load. Therefore, wind speed and snow depth according to return periods for design load estimation were calculated by frequency analysis using the weather data(maximum instantaneous wind speed, maximum wind speed, maximum depth of snow cover and fall) of 68 regions in Korea. Equations for estimating maximum instantaneous wind speed with maximum wind speed were developed for all, inland and seaside regions. The results were about the same as the current eqution in general. Design wind speed and snow depth according to return periods were calculated and Local design wind load and snow load depending on return periods were presented together with iso-wind speed and iso-snow depth maps. The calculated design snow depth by maximum depth of snow cover were higher than design snow depth by maximum depth of snow fall. Considering wind speed and snow depth, protected cultivation is very difficult in Ullungdo, Gangwon seaside and contiguity inland regions, and strong structural design is needed in the west-south seaside against wind speed, and structure design of biological production facility in these regions need special consideration.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.3
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• pp.59-65
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• 2008

High-speed electrical motor has been studied for several applications, i.e. for direct-drive systems of centrifugal compressors and turbo blowers. This paper deals with a design consideration of electromagnetic, mechanical and thermal limits of high-speed induction motor for turbo blower. Basic design concept of high-speed motor was proposed. As the motor is to be operated at high speed, the losses are quite different from conventional low-speed machines. Especially, the increases of rotor eddy current and friction losses could lead to an overheated motor. So, we suggested a special cooling system to reduce temperature rise. And, based upon this design concept, the prototype induction motor(37[kW], 45,000[rpm]) for high-speed turbo blower was designed and 2-D electromagnetic field analysis was implemented. Finally, criteria to evaluate the characteristics of high-speed induction motor have been proposed and tested.

• Proceedings of the KSR Conference
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• 1999.11a
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• pp.130-138
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• 1999

This study was carried out about interior design of trailer car for Korean High speed Train of Maximum operating speed of 350km/h. The interior main item design of high speed train is performed in order to satisfy the function of speed, safety and comfort concerning the RAMSH, ENVIRONMENT, ACTIVITY AND INFORMATION, This paper focuses on what is the design principle concerning the above mentioned factors and how did we apply that in the korea high speed train.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.12
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• pp.2028-2038
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• 2003

High-speed feed drive systems have been widely used in the manufacturing and semiconductor industries. Specifications for high-speed systems require more advanced capabilities than conventional feed drive systems. It is necessary to devise special design concepts to achieve the level of performance for high-speed feed drive systems. In this paper, an integrated design method is proposed for high-speed feed drive systems in which the interactions between mechanical and electrical subsystems ought to be considered simultaneously during the design process. Based on the integrated design method, a nonlinear optimal design procedure of mechanical subsystems considering the Abbe and radius errors is accomplished through the design process of electrical subsystems satisfying the control stability and the saturation condition of actuators as well as the relative stability. Both mechanical and electrical parameters are considered as design variables. Simulations and numerical case studies show that the integrated design method of high-speed feed drive systems creates results satisfying the desired performances of mechatronic systems.

• Proceedings of the KSR Conference
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• 2005.05a
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• pp.285-290
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• 2005

In this paper, the general process of the conceptual design of high speed train system was introduced by the review of the design process of Korea High Speed Train. The development of a general design process of high speed train is necessary in order to lead a high speed railway market in the future. For the conceptual design of high speed train system, the goals to develop a new high speed train are set. The different high speed train configurations are chosen regarding traction power, bogie type, etc and repeatedly evaluated with respect to the requirements

• International Journal of Highway Engineering
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• v.12 no.2
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• pp.25-31
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• 2010

Road design guideline provides the directions on how to design a road alignment based on design speed, and this guideline has a design expectation in that design speed is supposed to be equal to the operating speed of drivers. Horizontal curve design is also based on design speed, and minimum radius is derived based on the drivers comfort while negotiating the curve. However, side friction reflecting drivers comfort is lower than a physical friction measured on wet road surface, therefore, it is reasonable to regard the criterion on minimum radius has a safety margin. Futhermore, the practical preference of choosing the larger radius than minimum leads to a noticeable gap between design speed and operating speed, so links to the violation of design expectation implicated in the guideline. In order to review this assumption, friction and operating speed at rural roads was measured and observed. As the results, a safety margin brought out by the gap between comfort-based friction and measured friction is qualitatively derived. Also, the gap between design speed and operating speed presumably caused by the safety margin and practical preference is analysed. By this, it is suggested that current design guideline should provides not only the minimum radius but also the management of road alignment design to minimize the gap between the design speed and operating speed.

• Proceedings of the KSR Conference
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• 2009.05b
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• pp.517-524
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• 2009

This paper proposes a magnetic analysis model and design method of transformer for the high-speed EMU. It has a many part of the consideration in design because the transformer in high-speed train has the multiple output. Also the output characteristic, weight, and size of transformer is an important factor. This research proposes a design method of transformer in high-speed EMU. And it is easy to design by using the analysis model in design the transformer through the establishment of the magnetic analysis model.