• Journal of the Korean Society for Precision Engineering
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• v.26 no.2
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• pp.94-100
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• 2009

In diesel engines, it is inevitable that the torsional vibration is produced by the fluctuation of engine torque. Therefore, it is necessary to establish preventive measures to diminish the torsional vibration. The sleeve spring type damper is one of the preventive measures for reducing the torsional vibration. In this study, a closed form equation to predict spring constant of the sleeve spring and torsional characteristic of the torsional vibration damper was proposed to calculate stiffness of the damper and verified their availability through the finite element analysis. The theoretical values have a good agreement with the results obtained by the finite element analysis. The results obtained from the equation derived enable the designers in actual fields to be more efficient.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.11a
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• pp.911-914
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• 2005

The vibrational characteristics of the piezoelectric disc for a torsional vibration transducer is theoretically studied in this paper. The characteristic equation of the piezoelectric annular disc has been derived from Newton's End law and Gibb's free energy equations. With an anisotropic material property of the disc, the characteristic equation has yielded resonance frequencies. Numerically-calculated results were compared with the values obtained by finite element analysis and experiments

• Journal of KSNVE
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• v.4 no.3
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• pp.319-325
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• 1994

The flucturation of the engine torque appears to be the major source of the torsional vibration of the automotive driveline. The reduction of this torsional vibration has become a significant problem, due to an increase in the flucturation of the torque of recent light weighted powered engines, along with the requirements of higher performance. The torsional vibration of the automotive driveline can be reduced by soothing the fluctuation by adjusting the torsional characteristics of the clutch-disc. Computer simulation of the engine- input gear train is a useful investigative tool on studying the torsional characteristics of the clutch-disc. In this paper, a dynamic model for the automotive driveline was developed, and the engine torque and drag torque of the model were evaluated withe experimental data. By executing a simulation using the model, it has become possible to obtain the clutch-disc torsional characteristics when the engine is idling and the clucth-disc torsional characteristics for reducing the torsional vibration has been suggested.

• Transactions of the Korean Society of Automotive Engineers
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• v.3 no.2
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• pp.102-111
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• 1995

The non-periodic fluctuation of the engine torque appears to be the major source of the torsional vibration of the automotive driveline. The reduction of this torsional vibration has become a significant problem along with the requirements of higher performance. The torsional vibration of the automotive driveline can be reduced by smoothing the fluctuation by adjusting the torsional characteristics of the clutch-disc. Computer simulation of the driveline is a useful investigative tool on studying the torsional characteristics of the clutch-disc. In this paper, a dynamic model for the automotive driveline was developed, and the engine torque of the model were evaluated with experimental data. By executing a simulation using the model, it has become possible to obtain the clutch-disc torsional characteristics for reducting the torsional vibration at creeping.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2009.10a
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• pp.344-350
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• 2009

According to torsional vibration characteristic of a damper clutch in auto-transmission, the input shaft system have occurred breakdown for the duration cycle and over-vibration happened on vehicle at specific condition. This paper describes the improvement of the torsional vibration of input shaft and the vehicle vibration by tuning of the damper clutch and suggests to the guide line about torsion characteristic on the design of damper clutch.

• Transactions of the Korean Society of Automotive Engineers
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• v.6 no.3
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• pp.88-96
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• 1998

The rattle noise is the most significant in many kinds of manual gearbox nioses, which is generated at the idle stage of the engine operation. The main torsional vibrat- ion source of the driveline is the fluctuation of the engine torque. The gear rattle is impacts generating in the backlash of the free gear due to this torsional vibration. Many researchers reported the clutch torsional characteristic optimization method to reduce the idle gear rattle but only few of them give sufficient consideration to the system parameters like gear backlash, drag torque, system inertia, inertia distribution, engine torque fluctuation, idle engine rotation speed, and accessory load. In this paper, influence rate of system parameters on the gear rattle is presented and counterplans like backlash reduction, drag torque increase, inertia addition, inertia distribution modification and engine torque characteristic control are suggested.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.06a
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• pp.1280-1285
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• 2000

The paper deals with a theoretical study on the vibrational characteristics of piezoelectric torsional transducers. The differential equations of piezoelectric torsional motion have been derived in terms of the circumferential displacement and the electric potential. Applying mechanical and electrical boundary conditions has yielded the characteristic equations of natural vibration in several transducer types. Numerical results have clarified the effect of the piezoelectric phenomenon on the mechanical resonance and the effect of the elastic block of a Langevin-type transducer on the natural frequency.

• Journal of KSNVE
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• v.10 no.6
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• pp.955-962
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• 2000

The paper deals with a theoretical study on the vibrational characteristics of piezoelectric torsional transducers. The differential equations of piezoelectric torsional motion have been derived in terms of the circumferential displacement and the electric potential. Applying mechanical and electrical boundary conditions has yielded the characteristic equations of natural vibration in several transducer types. Numerical results have clarified the effect of the piezoelectric phenomenon on the mechanical resonance and the effect of the elastic block of a Langevin-type transducer on the natural frequency.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2000.10a
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• pp.249-256
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• 2000

The visco-elastic dampers were used to improve the torsional responses of an asymmetric buildings. The modal characteristic equation of an asymmetric structure with added viscoelastic dampers were derived using the complex modal analysis method. Parametric study has been performed based on the modal characteristics, and the appropriate condition for compensating the stiffness eccentricity was investigated. According to the results the torsional response of the asymmetric buildings could be improved significantly once the dampers were properly placed

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.15 no.12 s.105
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• pp.1416-1421
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• 2005

This paper presents an analytical approach for the vibration characteristics of a piezoelectric disc for torsional vibration transducers. The characteristic equation of the piezoelectric annular disc has been derived from Gibbs' free energy equations and mechanical and electrical equilibrium. With an anisotropic material properties of the disc, the characteristic equation has yielded resonance frequencies. Numerically-calculated results have been compared with the results obtained by the finite element analysis and experiments and have confirmed the validity of the theoretical analysis.