• Bulletin of the Society of Naval Architects of Korea
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• v.44 no.4
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• pp.11-15
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• 2007

• 지반과기술
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• v.3 no.4
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• pp.62-67
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• 2006

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.11a
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• pp.179-184
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• 2001

대부분의 제품 생산 시에는 시제품을 제작하여 이에 대한 성능 심사를 통해 미비한 부분을 보완하기 위한 재설계 작업과정을 필요로 한다. 설계 작업에 가장 중요한 부분인 특정 설계 변수에 대한 민감도의 파악은 설계 작업의 핵심적인 역할을 하고 있다. 대개의 경우 진동설계를 위한 설계변수로 구조물의 단위면적, 길이, 재료의 성질과 같은 물리적인 변수를 많이 활용하고 있으며 이러한 변수들에 대한 민감도 해석 기법들은 이미 많은 연구를 통해 실용화되고 있다. 그러나 이러한 변수만으로는 주어진 조건을 만족하도록 설계하기가 어려운 경우가 있다. 이런 경우는 부가구조물을 첨가하여 저진동 설계조건을 만족하는 구조물을 제작하는 것이 보편적이다. 한편, 구조물의 최적화 과정에서 고유진동수를 고려해야 하는 경우가 많다. 저주파 영역의 문제에서는 첫번째 고유진동수가 구조물의 진동량에 관계되는 중요한 요인이 되고, 또한 공진에 의한 문제가 발생했을 경우에는 고유진동수를 옮겨서 공진을 회피할 수 있기 때문이다. 본 연구에서는 에어컨 실외기의 진동을 저감하고 그로 인한 구조기인 소음을 저감하기 위하여 음압 레벨을 바탕으로 정한 관심 주파수 영역에 고유진동수가 존재하지 않도록 부가구조물을 최적화하였다. 최적화에 필요한 민감도는 신뢰성 있는 유한요소 모델을 구성하는 것이 쉽지 않으므로 실험으로 구한 주파수 응답함수를 이용하였다.

• Journal of the Korean Institute of Gas
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• v.13 no.1
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• pp.9-13
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• 2009

A cause of noise and vibration which come from a Combustion of gas heater are a combustion roar and Combustion oscillation. A character of a combustion roar is that sound pressure is distribute with broad band frequency. otherwise, The presence of combustion oscillation caused by positive Feed Back in Combustion Chamber break out a noise and vibration. Accordingly, The method that be solved a noise and vibration is to make each natural frequency different frequency. first, in order to solve problem, we control ratio of fuel and air. that is, Keep away resonance. second, in order to changing natural frequency of Combustion Chamber, We changed the shape of Economizer.

• Transactions of the KSME C: Technology and Education
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• v.3 no.2
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• pp.117-124
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• 2015

Recently, noise reduction in room air conditioner has been one of the most important issues as well as cooling efficiency. A rotary compressor is widely used in room air conditioners. But, the rotary compressor is the dominant vibration/noise source in an air conditioner. A number of studies have been conducted on reducing rotary compressor vibration/noise through improving muffler and resonator design. However, a noise delivering path between compressor and pipe is not fully taken into consideration. In this paper, the vibration analysis model of rotary compressor is modeled using RecurDyn and experimental validation is presented.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.10a
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• pp.699-700
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• 2014

고속도로에 아스팔트 저소음포장이 시공된 현장의 소음조사를 통하여 저소음 아스팔트 포장의 소음저감효과를 분석하였다. 교통량 및 시공시기에 차이가 있는 세 현장에 대하여 측정 시기를 달리하여 저소음포장의 사용 기간에 따른 소음저감효과의 변화를 분석하였으며, 공동주택의 소음대책을 위해 시공된 현장에서는 세대내에서 실질적인 저감효과에 대해 분석하였다. 이 결과를 토대로 저소음포장을 도로소음 대책수단으로 적용을 검토할 경우 설계자가 고려해야할 사항을 제시하고자 하였다.

• Journal of KSNVE
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• v.11 no.3
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• pp.377-382
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• 2001

• 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.

• Aerospace Engineering and Technology
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• v.5 no.2
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• pp.102-107
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• 2006

In this study, the dynamic environment of satellite consists of excessive vibration at low frequency and irregular acceleration transferred by launch vehicle structure. Excessive vibration at low frequency is generally approximated by a sinusoidal wave from 100Hz to 200Hz and primarily used to preliminary design The random vibration is created by structural vibration due to the combustion of launch vehicle, separation stage and external aerodynamic noise. these are transferred to the adapter structure between satellite and launch vehicle through the structure of launch vehicle. random vibration is being specified for acceptance tests, screening tests, and qualification tests, because it has been shown that random vibration more closely represents the true environments in which the electronic equipment must operate.

• Journal of the Korean Geosynthetics Society
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• v.14 no.3
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• pp.1-12
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• 2015

During installing sheet piles for an impermeable wall or a retaining wall, vibratory hammers are widely used. Among vibratory hammers, a hydraulic hammer is used most commonly. However, a hydraulic hammer causes excessive vibration and noise due to resonance by change of natural frequency according to movements of eccentric shaft when the hammer starts and stops. In this study, new variable amplitude type hammer is developed in order to reduce the vibration and noise due to resonance produced in starting and stopping the hammer. By controlling horizontal angle in two pairs of eccentric body inside of the hammer, the amplitude and vibration of the new hammer can be controlled. The performance tests with the new hammer and existing hammers such as the hydraulic hammer and electric hammer are carried out, and the new hammer shows reduced vibration and noise results in comparison with existing hammers from performance tests. Also, this study shows that penetration rates of sheet pile using the new hammer increase due to impellent force of a backhoe in comparison with the electric hammer and penetration rate increase in comparison with a general hydraulic hammer, since the new hammer can control the amplitude during penetration of sheet pile according to soil condition.