• KEPCO Journal on Electric Power and Energy
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• v.1 no.1
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• pp.181-188
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• 2015

The non-contact permanent magnet gear has advantages of high efficiency and improved reliability. It has other advantages of no mechanical friction loss, very little noise and vibration, and no need for lubricant. With these advantages, the non-contact permanent magnet gear that solves the physical contact problem of the mechanical gear has drawn attention. Due to this unique non-contact characteristic, the non-contact permanent magnet gear which is capable of non-contact torque transmission has replaced mechanical gear. The mechanical gears which is in many fields of the modern industry, is used mostly for power transmitting mechanical devices. However, it also has the problem of a low torque density, which requires improvement. In this paper, a novel pole piece shape is proposed in order to improve the problem of low torque density of the non-contact permanent magnet gear. The experiment data required for predicting the relationships among them are obtained using finiteelement Operating method based on two-dimensional (2-D) numerical analysis. Therefore, this paper derived an optimal model for thenon-contact permanent magnet gear with the novel pole piece using the Box-Behnken design, and the validity of the optimal design of the proposed pole piece shape through variance analysis and regression analysis demonstrated. In this paper, we performed the thransfer torque analysis in order to improve the torque density and power density, we have performed on optimal design of proposed pole piece shape using box-behnken.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.11a
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• pp.508-512
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• 2004

This paper described operation and vibration characteristics of 'Tail-Fan' performance test system. KARI(Korea Aerospace Research Institute) developed 'Tail-Fan' system as a kind of helicopter anti-torque system(ATS) and designed ATS performance test-rig for Tail-Fan system performance test. Test-rig consists of driving parts, supporting parts and rotating parts. For Tail-Fan system performance tests, firstly, test-rig operation tests were carried out for verification of design specifications. Secondly, natural frequencies of fan blade and test-rig were measured respectively. Lastly, to find the operation rotating speed for performance tests, vibration tests using accelerometers on tail gear box(TGB) were carried out. Through the fanplot and vibration test results, Tail-Fan performance test conditions to avoid a resonance were found and performance tests were well done safely.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.11b
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• pp.41-44
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• 2005

This paper described improvement and operation of a 'Tail-Fan' anti-torque performance test system KARI (Korea Aerospace Research Institute) developed a 'Tail-Fan' anti-torque system of a helicopter and a performance test-rig to test the performance of the Tail-Fan. The test-rig was improved for full rotating test in 4300rpm(100%). Machinery and hydraulic parts ware changed to reduce vibration and to increase safety. To find the operation rotating speed for the performance test, vibration test were carried out rising accelerometers on tail gear box. The performance test conditions of the Tail-Fan to avoid a resonance were found from vibration test results. The Tail-Fan operation tests were performed safely frier to carry out performance test.

• Journal of the Korea Institute of Military Science and Technology
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• v.18 no.1
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• pp.8-14
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• 2015

Transmission of a tracked vehicle designed for multiple functions such as steering, gear-shifting, and braking is a core component of heavy vehicle to which the power is transferred based on combined technology of various gears, bearing, and fluid machineries. Robustness and durability of transmission, however, have been issued due to a large number of driving units and sub-components inside its body. Particularly, transmission housing is important structure which supports the transmission, and is made of aluminum alloy. Thus, structural robustness against such mechanical loading or vibration must be attained. Structural reliability evaluation through FEM analysis can save time and cost of the actual tests. In this study, structural evaluation is conducted on output housing of transmission, which is core component of tracked vehicle, using the simulation program. In addition, transmission dynamo test is performed to evaluate structural robustness of the output housing against the vibration which can be produced during the transmission operation.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11a
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• pp.329.2-329
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• 2002

This paper presents an improved escalator dynamic model so as to reflect the experimental observation on the pseudo-resonance affected by load applied. The experimental evidence reveals that backlash of gearbox as well as sag of driving chain are most critical factors to the pseudo-resonance in escalators. The dynamic model effectively reflects vibration characteristics measured in real escalators with respect to different conditions of driving chain and the number of passengers. (omitted)

• Journal of Applied Reliability
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• v.14 no.4
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• pp.208-212
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• 2014

An experimental gear-box was set-up to simulate the real situation of the wind-turbine. Artificial cracks of different sizes were machined into the gear. Vibration signals were acquired to diagnose the different crack fault conditions. Time-domain features such as root mean square, variance, kurtosis, normalized 6th central moments were used to capture the characteristics of different crack conditions. Normal condition, 1 mm crack condition, 2mm crack condition, 6mm crack condition, and tooth fault condition were compared using ANFIS and DAG-SVM methods, and three different DAG-SVM models were compared. High-pass filtering improved the success rates remarkably in the case of DAG-SVM.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.15 no.4 s.97
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• pp.421-428
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• 2005

This paper described operation and vibration characteristics of a 'tail-fan' anti-torque performance test system. KARI (Korea Aerospace Research Institute) developed a 'tail-fan' anti-torque system of a helicopter and a performance test-rig to test the performance of the tail-fan. The performance test-rig consists of driving, supporting and rotating parts. In the process of the performance test, firstly, operation test of the test-rig were carried out to verify design specifications. Secondly, natural frequencies of fan blade and test-rig were measured respectively. Lastly, to find the operation rotating speed for the performance test, vibration test were carried out using accelerometers on tail gear box. The performance test conditions of the tail-fan to avoid a resonance were found from the fan-plot and vibration test results. The tail-fan performance tests were well done safely.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2009.04a
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• pp.78-83
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• 2009

In this study, computer applied engineering (CAE) techniques are fully used to conduct structural and dynamic analyses of a whole huge wind turbine system including composite blades, tower and nacelle. For this study, computational fluid dynamics (CFD) is used to predict aerodynamic loads of the rotating wind-turbine blade model. Multi-body dynamic structural analyses are conducted based on the non-linear finite element method (FEM) by using super-element method for composite laminates blade. Three-dimensional finite element model of a wind turbine system is constructed including power train(main shaft, gear box, coupling, generator), bedplate and tower. The results for multi-body dynamic simulations on the wind turbine's critical operating conditions are presented in detail.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2012.10a
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• pp.583-586
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• 2012

Wind turbine industry is booming and spending a lot on research for improving the performance of its present machines and increasing their capacity. Wind turbine requires service life of about 20 years and each canponents of wind turbine requires high durability, because installation and maintenance costs are more expensive than generated electricity by wind-turbine. So the design of wind turbine must be verified in various condition before production step. For this work, high reliability model for analysis is required. Drivetrain model is modeled by multibody dynamic modeling method. The model constituted with rotor blades, hub, main shaft, gear box, high speed shaft and generator. Natural frequency and torsional stiffness of drivetrain are calculated and analyzed.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.11a
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• pp.119-124
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• 2000

The 3-stage centrifugal compressor is used in order to measure the noise spectra of compressor, and analyze the results. Two cases are investigated for compressor noise components. Case I includes total system such as compressor, inter-cooler, motor, and Case II excludes cooling system. BPF tonal noise is important in compressor, and cooling system including inter-cooler contributes to broadband noise. Also, motor, gear box, and motor cooling fan are the second contributions to total compressor noise. Centrifugal compressor flow-field is calculated using two-dimensional grid and Navier-Stokes equations. Static pressure increases, and total pressure decreases, as air passes through the compressor components.