• Journal of Magnetics
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• v.18 no.3
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• pp.260-267
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• 2013

In this paper a general 2-D model of a large air-gap synchronous machine either with non-magnetic or magnetic core rotor is investigated and electrical characteristics of the machine are analytically calculated. Considering the general model, analytical equations for magnetic field density in different regions of the large air-gap machine are calculated. In addition, self and mutual inductances in the proposed model of the machine have been developed, which are the most important parameters in the electromagnetic design and transient analysis of synchronous machines. Finite element simulation has also been performed to verify the obtained results from the equations. Analytical results show good agreement with FEM results.

• Journal of the Korean Society for Precision Engineering
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• v.18 no.11
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• pp.34-41
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• 2001

This study is to investigate the energy absorption characteristics of CFRP(Carbon-Fiber Reinforced Plastics) tubes on static and dynamic tests. Axial static compression tests have been carried out using the static testing machine(Shin-gang buckling testing machine) and dynamic compression tests have been utilized using an vertical crushing testing machine. When such tubes are subjected to crushing loads, the response is complex and depends on the interaction between the different mechanisms that could control the crushing process. The collapse characteristics and energy absorption have been examined for various tubes. Energy absorption of the tubes are increased as changes in the lay-up which may increase the modulus of tubes. The results have been varied significantly as a function of ply orientation and interlaminar number.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2002.04a
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• pp.643-648
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• 2002

In the cutting of plate steel, the quality of the cut surfaces is strongly dependent on the cutting conditions such as cutting speed, kerf width, plate thickness, length of tip-specimen and oxygen pressure etc. the cutting tests of plate steel were carried out using CNC gas cutting machine. this paper deals with cutting characteristics of plate steel using CNC cutting machine. the width of cutting entrance and exit, the surface roughness of cutting surfaces and the cutting surface are examined at various cutting conditions.

• International Journal of Precision Engineering and Manufacturing
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• v.8 no.1
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• pp.32-37
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• 2007

The outer diameter finishing grinding process required for ferrules, which are widely used as fiber optic connectors, is carried out by high-precision centerless grinding machines. In this study, the thermal characteristics of such a machine, for example, the temperature distribution, temperature rise, and thermal deformation, were estimated based on a virtual prototype and the heat generation rates of heat sources related to normal operating conditions. The prototype consisted of a concrete-filled bed. hydrostatic grinding wheel (GW) and regulating wheel (RW) spindle systems, a hydrostatic RW feed mechanism, a RW swivel mechanism, and on-machine GW and RW dressers. The reliability of the predicted results was demonstrated using temperature characteristics measured from a physical prototype. The predicted and measured results indicated that this particular high-precision centerless grinding machine had very stable thermal characteristics.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.32-36
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• 2002

High-speed movement and high-precision machining are the two most important requirements of present machine tool structures to reduce machining time and to increase the precision of products in various industrial fields such as semiconductor, automobile, and mold fabrication. The high speed operation of machine tools tue usually restricted not only by the low stiffness but also by the low damping of machine tool structures, which induces vibration during high speed machining. If the damping of machine tool structures is low, self induced or regenerative vibrations are bound to occur at high speed operation because the natural frequencies of machine tool structures can not be increased indefinitely. Therefore, the high damping capacity of a machine tool structure is an important factor for high speed machine tool structures. Polymer concrete has high potential for machine tool bed due to its good damping characteristics. In this study, a polymer concrete bed combined with welded steel structure i.e., a hybrid structure was desisted and manufactured for a high-speed gantry-type milling machine through static and dynamic analyses using finite element method. Then the dynamic characteristics were tested experimentally.

• Proceedings of the KSME Conference
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• 2001.06c
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• pp.202-206
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• 2001

Machine tool chatter is the self-excited vibration generated by chip thickness variation and severely degrades the quality of machined surface. The incidence of chatter is greatly affected by the dynamic characteristics of machine tool structure. Therefore, the cutting dynamics in the parallel machine tool is to be carefully studied considering the dynamic characteristics of parallel mechanism. In this paper, the vibration model of parallel machine tool is derived, in which the legs of the parallel mechanism are considered as spring-damper systems. The chatter stability charts for various machining parameters are examined with the example of the cubic parallel mechanism that is specially designed for machine tool use.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2007.10a
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• pp.21-24
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• 2007

This paper deals with introduction of testing equipments for the evaluation of dynamic tensile characteristics of auto-body steel sheets and the crashworthiness of auto-body members. The servo-hydraulic high speed material testing machine was developed for tensile tests at the intermediate strain rate to obtain the tensile material properties at the strain rate under 500/sec. The split Hopkinson bar apparatus using the elastic wave was developed for dynamic material characteristics at the high strain rate ranged from 1,000 to 10,000/sec. The servo-hydraulic high speed crash testing machine is the equipment for the evaluation of the collapse load and crashworthiness of auto-body members. High speed carrying truck crashes to specimen with the maximum velocity of 17 m/sec.

• International Journal of Advanced Culture Technology
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• v.10 no.3
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• pp.360-370
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• 2022

Demand for machine learning systems continues to grow, and cloud machine learning platforms are widely used to meet this demand. Recently, the performance improvement of the application processor of smartphones has become an opportunity for the machine learning platform to move from the cloud to On-Device AI, and mobile applications equipped with machine learning functions are required. In this paper, machine learning tools for mobile applications are investigated and compared the characteristics of these tools.

• Transactions of The Korea Fluid Power Systems Society
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• v.8 no.4
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• pp.1-8
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• 2011

Injection molding machine is the assembly of many kinds of mechanical and fluid power part and electro-electronic control system. From in these, fluid power is a part where becomes the first core of this machine. Fluid power systems of injection molding machine are modelled and analyzed using a commercial program AMESim. The analysis model which is detailed about the parts applied a publishing catalog data. Sub system models which is divided according to functional operation are made and its analysis results shows how design parameters work on operational characteristics like displacement, pressure, flow rates at each node and so on. Total fluid power circuit model is also made and analyzed. The results made by analysis will be used design of fluid power circuit of injection molding machine.

• Transactions of The Korea Fluid Power Systems Society
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• v.8 no.4
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• pp.24-31
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• 2011

Double-color Injection molding machine is the assembly of many kinds of mechanical, fluid power part and electric electronic control system. From in these, fluid power is a part where becomes the first core of this machine. Fluid power systems of double-color injection molding machine are modelled and analyzed using a commercial program AMESim. Partial system models which is divided according to functional operation are made and its analysis results shows how design parameters work on operational characteristics like pressure, flow rates, displacement at each node and so on. Analysis modeling and compared the data which gets from experiment and the analysis result which has a reliability got data. The results made by analysis will be used design of fluid power circuit for developing a double-color injection molding machine.