• Journal of the Korean GEO-environmental Society
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• v.14 no.9
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• pp.21-30
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• 2013

Because the noise and vibration regulations in domestic areas are being tightened more and more, a more environmentfriendly method than the current low-noise & low-vibration methods is needed. In this study, the characteristics of screw concrete piles for reduction of noise and vibration were explained, and during pilot tests the noise and vibration were measured. The measured vibration value is satisfied with the vibration regulations at 7.5m distance from the source. The measured noise value is exceeded over about 2dB(A) at the 15.0m distance from the source but these values are about 5~20dB(A) less than the measured values of the current low-noise & low-vibration method.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1990.10a
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• pp.71-77
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• 1990

This paper describes the experimental analysis of the vibration and noise reduction for the washing machine of the home appliances. For the washing machine, the customers always feel electrical and mechanical noise and vibration. First of all, when the dehydration process is working, the washing machine has nonlinear problems and boundary conditions are varied with time. Therefore these problems are very complicated and difficult to analyze. We verify the sources of the noise and vibration and consider the countermeasure to reduce the noise and vibration level of the washing machine.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.6 no.2
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• pp.67-75
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• 1997

The noise . vibration characteristics of Hypoid gears which were made from three seperate materials(SCM, TSCM, SNCM) under the identical process were investigated for the sake of durability improvement of differential gear compatible with low level noise gear set. For this study, we developed a rig experimental equipment which can perform close noise.vibration experiment of differential gear. Consequently, we could analyze the noise.vibration characteristics of final reduction gear by materials, and also we observed changes in both metallic structure and hardness according to the materials of pinion gear. In addition to this, the correlation between the vibration of the differential gear and the interior noise of the passenger vehicles was proved by analyzing the results of rig vibration experiment and field noise test.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.06a
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• pp.1273-1279
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• 2000

A new concept of piezoelectric smart panels for noise reduction in wide band frequencies is proposed and their possibility is experimentally investigated. The proposed panels are based on active and passive methods. They use piezoelectric smart structure technology for active noise reduction at low band frequencies and passive sound absorbing materials for mid-range of noise frequencies. To prove the concept of piezoelectric smart panels, an acoustic measurement experiment was performed. The smart panels exhibit a good noise reduction in middle and high frequency ranges due to the mass effects of absorbing materials or/and the air gap. The use of piezoelectric smart panel renders noise reduction large at resonance frequency. Another concept of smart panel that uses piezoelectric damping is experimentally investigated. Since piezoelectric dampings can reduce vibration and noise at resonance frequencies with simple shunt circuit, they have merits in terms of economy and simplicity. Dissipated energy method(DEM) is adopted to tune the shunt circuit precisely in piezoelectric dampings. Noise reduction at multiple resonance frequencies is demonstrated.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.21 no.6
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• pp.546-552
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• 2011

In this study, noise sources of a reducer which is combined a spiral bevel gear and a planocentric gear are identified by experimental method and the noise was reduced by the structure modification of the reducer. In order to identify the noise sources, noise and vibration signals were measured by microphone and accelerometer and these signals were analyzed with waterfall plot. In addition, the frequency response functions were obtained to prove the noise and vibration sources. It was found that the resonance was generated by the gear mesh frequencies and natural frequency of the reducer. The noise of the reducer could be reduced by structure modification.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2011.04a
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• pp.51-56
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• 2011

In this study, noise sources of a reducer which is combined a spiral bevel gear and a planocentric gear are identified by experimental method and the noise was reduced by the structure modification of the reducer. In order to identify the noise sources, noise and vibration signals were measured by microphone and accelerometer and these signals were analyzed with waterfall plot. In addition, the frequency response functions were obtained to prove the noise and vibration sources. It was found that the resonance was generated by the gear mesh frequencies and natural frequency of the reducer. The noise of the reducer could be reduced by structure modification.

• Journal of KSNVE
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• v.9 no.4
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• pp.730-737
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• 1999

This paper illustrates the sound vibration phenomenon of mono type TV set produced by spearker and suggests guidelines for reducing the noise induced by the sound vibrations. In order to illustrate the sound vibration phenomenon, the structural acoustic coupled analysis for the grill and cavity of speaker and structural analysis for main frame are performed. To veify the structural analysis results, experimental modal test is carried out. It is found that the acoustic excitation in the cavity is negligible and main sound vibrations occur near the bottom of TV set. An improved model is found by doing structural modifications based on structural analysis and sound vibration tests are performed to verify the validation of the improved model. The obtained results are applied to similar models and design guide lines for noise reduction are suggested.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.11a
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• pp.686-689
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• 2006

In a wheel loader, the tail-pipe is installed at the exhaust tube of muffler for the reduction of exhaust noise and the cooling of engine room however, the cabin noise level can be largely increased due to the tail-pipe. In this paper, to grasp and reduce the cabin noise, a series of noise and vibration tests were carried out in addition to numerical simulations. As a result, the transmission path of exhaust noise toward the cabin was exactly identified and the improved shape of tail pipe, that can reduce the cabin noise, was derived through various numerical simulations and real tests.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.16 no.12 s.117
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• pp.1238-1243
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• 2006

In a wheel loader, the tail-pipe is installed at the exhaust tube of muffler for the reduction of exhaust noise and the cooling of engine room, however, the cabin noise level can be largely increased due to the tail-pipe. In this paper, to grasp and reduce the cabin noise, a series of noise and vibration tests were carried out in addition to numerical simulations. As a result, the transmission path of exhaust noise toward the cabin was exactly identified and the improved shape of tail pipe, that can reduce the cabin noise, was derived through various numerical simulations and real tests.

• Proceedings of the SAREK Conference
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• 2005.11a
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• pp.506-510
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• 2005

This study shows work on the properties of noise and vibration in Whirlpool bath and plan for its reduction. Totally through 3 steps. we found out the properties of noise and vibration. various anti-vibration design for an effeciency test is conducted. By Anti-vibration for the pump causing vibration, about 4dB(A) was reduced. Moreover. by anti-vibration construction fixing the bathtub frame. about 3db(A) could be reduced. In the case of anti-vibration construction about the wall around the bathtub. and spreading damping paint on the bathtub. the noise was reduced.