• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2005.05a
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• pp.479-482
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• 2005

To improve the efficiency of fossil power plant, the higher steam temperature and pressure are required. Ultra super critical(USC) system meets very well this requirement. The HIP rotor is one of the most important parts of turbine in USC system and its material is easy to crack during hot forging. In this study, the upsetting and cogging process far $12\%Cr$ ESR ingot was analyzed and it is suggested a optimum process to avoid surface crack. The results were verified by test product with 4,200 tonnage press.

• KEPCO Journal on Electric Power and Energy
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• v.7 no.2
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• pp.269-275
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• 2021

The turbine rotor, one of the main facilities in a power plant, it generates electricity while rotating at 3600 RPM. Because it rotates at high speed, it requires careful management because high vibration occurs even if it is deformed by only 0.1mm. However, bending occurs due to various causes during turbine operating. If turbine rotor bending occurs, the power plant must be stopped and repaired. In the past, straightening was carried out using a heating torch and furnace in the field. In case of straightening in this way, it is impossible to proceed systematically, so damage to the turbine rotor may occur and take long period for maintenance. Long maintenance period causes excessive cost, so it is necessary to straighten the rotor by minimizing damage to the rotor in a short period of time. To solve this problem, we developed a turbine rotor straightening equipment using high-frequency induction heating equipment. A straightening was validated for 500MW HIP rotor, and the optimal parameters for straightening were selected. In addition, based on the experimental results, finite element analysis was performed to build a database. Using the database, a straightening amount prediction model available for rotor straightening was developed. Using the developed straightening equipment and straightening prediction model, it is possible to straightening the rotor with minimized damage to the rotor in a short period of time.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1997.10a
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• pp.96-100
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• 1997

A design modification was made on the 9-th stage wheel dovetail of a high-intermodiate pressure (HIP) turbine rotor for a fossil power plant that necessitates the use of new long-shank buckets for the row. A bucket vibration test is necessary to verify that the new 9-th stage buckets have adequate frequency margin from a nozzle passing frequency when running at speed. A finite element analysis (FEA) has been performed using a commercial S/W to approximately estimate bucket natural frequencies, and thus to help the vibration test. A row of the new buckets has been assembled on the HIP rotor for the vibration tests using dynamic balancing facilities. The tests have been done during deceleration run with air excitation. The test results are compared with the calculation using our empirical formula, and show that the modified design meets the frequency-margin requirements.

• Journal of KSNVE
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• v.8 no.2
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• pp.331-335
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• 1998

A design modification was made on the 9-th stage wheel dovetail of a high-intermediate pressure (HIP) turbine rotor for a fossil power plant that necessitates the use of new long-shank buckets for the row. A bucket vibration test is necessary to verify that the new 9-th stage buckets have adequate frequency margin from a nozzle passing frequency when running at speed. A finite element analysis (FEA) has been performed using a commercial S/W to approximately estimate bucket natural frequencies, and thus to help the vibration test. A row of the new buckets has assembled on the HIP rotor for the vibration tests using dynamic balancing facilities. The tests have been done during deceleration run with air excitation. The test results are compared with the calculation using our empirical formula, and show that the modified design meets the frequency-margin requirements.

• Proceedings of the KIEE Conference
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• 2004.07d
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• pp.2420-2422
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• 2004

In this paper, we developed a miniaturized humanoid having the new joint mechanism. In general, the high torque actuator and the joint mechanism having three coincided axes are important in development of the miniaturized humanoid. By using the swash plate, which is generally used in three axes rotor mechanism, we developed a new three-coincided-axes joint mechanism and a miniaturized humanoid having the joint mechanism at its hip and ankle joints. Since the joint mechanism has a pair of parallel drive motors for each axis, the driving torque of the joint mechanism is very high. Futhermore, thanks to the three-coincided-axes mechanism, the solution of the inverse kinematics is simple and computationally efficient, and the resulting walking behavior of the humanoid becomes natural.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.05a
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• pp.190-195
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• 2002

The intermittent high vibration has been occurred one or two times a day for a 500MW large steam turbine during 5 months. This abnormal vibration was caused by the rubbing between the rotor and the carbide accumulated on the seal tooth of oil deflector. It was found that the accumulated carbide was insulation material installed on the HIP casing from the examination of the chemical composition. Also, this paper presents the mechanism of the intermittent high vibration and the proper method to eliminate this vibration problem. This result would be good practice to find the solution of similar high vibration in the steam turbines for power plant as well as industrial rotating machineries.

• Proceedings of the Korean Institute of Industrial Safety Conference
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• 1998.11a
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• pp.353-358
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• 1998

Vibrations exposured to human whole-body are transmitted through the contact area of a human body, such as feet, hip and back directly in contact with vibrating surface. they apparently leads to the decrease of human comfort, the reduction of working efficiency or normal activities, and, furthermore, causes the loss of health and safety. In this study, UH-1 vibration has been measured to produce the flight-time limitation at each mission Results of this study show that the most significant peaks appear at a main rotor blade-passage frequency and that the vibration level in ground is higher than that in airborne In addition, it is shown that the most affective aspect for the flight-time limitation is ground vibration level

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.12 no.11
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• pp.897-903
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• 2002

The periodic high vibration has been occurred one or two times a day for a 500 MW large steam turbine during 5 months. This abnormal vibration was caused by the rubbing between the rotor and the carbide accumulated on the seal tooth of oil deflector. It was found that the accumulated carbide was insulation material installed on the HIP casing from the examination of the chemical composition. Also, this paper presents the mechanism of the periodic high vibration and the proper method to eliminate this vibration problem. This result would be good practice to find the solution of similar high vibration in the steam turbines for power plant as well as industrial rotating machineries.