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

• Proceedings of the KSME Conference
• /
• 2007.05a
• /
• pp.1063-1068
• /
• 2007

The present study describes the effects of music and vibroacoustic stimuli to the relaxation of human body. We have carried out the experiment on 6 human subjects of which are composed 3men and 3women. We have investigated the electroencephalogram(EEG) of all subjects before and after the stimuli of which are made a strong noise or the meditatiom music and the acoustic vibration. The vibroacoustic device has transmitted meditation music as vibration between 20Hz and 250Hz to the body. From the experimental results, we made sure the effects that the meditation music and vibroacoustic stimuli influenced the stress reduction of human body for good as alpha-wave was increased continuously during the good stimuli and after that.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2011.11a
• /
• pp.119-121
• /
• 2011

플로팅 구조물의 거동은 함체의 크기에 따라 많은 영향을 받는 것으로 알려져 있다. 그에 따라 함체의 거동을 표현하기 위한 해석모델은 해석의 단순성, 파랑하중과의 상호작용의 연계정도를 고려하여 그 형태 또한 달라지게 된다. 해석모델에는 함체에 발생하는 진동을 효과적으로 저감시키기 위한 진동저감시스템을 포함하는 경우도 있다. 함체의 해석모델에 진동저감시스템의 해석모델이 연계되면 이들 해석모형이 상호결함된 통합모형은 더욱 복잡한 경향을 가지게 된다. 본 연구에서는 함체의 해석모형을 강체거동을 하는 단순한 모형으로 가정하고 해석모형이 가지는 동적특성을 ICA기법을 통하여 효과적으로 추정하는 기법을 다룬다. 이를 위하여 실험과 ICA 기법을 이용하여 동적추정이 가능한지를 평가해보고 이를 플로팅 구조물에 적용하기 위한 기법을 다룬다.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.36 no.3
• /
• pp.285-290
• /
• 2008

Pyrotechnic shock or pyroshock is characterized as a transient vibration phenomena which shows large acceleration and high frequency range up to 10kHz during the operation of separation devices where explosives are used. During the flight of a launch vehicle, pyro-shock is mainly generated at several events such as satellite separation, fairing separation and stage separation. In this paper, characteristics of pyroshock are introduced briefly, and PEEK washer shock absorber is applied for the reduction of pyroshock in the high frequency range. With some electronic devices, reduction characteristic of pyroshock using washer type shock absorber are studied. Random vibration tests are also performed for the verification of vibrational characteristics.

• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.20 no.5
• /
• pp.557-563
• /
• 2007

Rain-wind induced cable vibration can cause serious problems in cable-stayed bridge. External dampers attached to the cables have become widely accepted as an effective means for stay-cable vibration suppression. For very long stay-cables, however, such damper systems are rendered ineffective, as the dampers need be attached near the end of cables for aesthetic reasons. A recent study by the authors proposed that a movable anchorage system is replaced direct fixed support of the cable with a support through a bearing and damper. This paper extends the previous work by adding active control system to mitigate the cable vibration. The response of a cable with the proposed active control system is obtained and then compared to those of the cable with and without an external passive damper. The results show that the active control system can provide superior protection than the passive control system for a cable vibration.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.17 no.2
• /
• pp.54-61
• /
• 2013

Stay cable has a strong axial rigidity due to large initial tension and, on the other hand, it has a weak laterally flexural rigidity. Wind loads or traffic loads cause the cables to vibrate significantly and affect the mechanical properties and the performance of cables of cable-stayed bridge (CSB). Therefore, the development of vibration reduction design is an urgent task to control the vibration vulnerable long-span bridges. As Friction damper (FD) shows to reduce the amplitude and duration time of vibration of cable of CSB from measured date in field test, friction damper can be considered that it is effective device significantly to reduce the amplitude and duration time in vibration of cable of CSB under traffic load, wind load and so on. Vibration characteristics of cable can change according to manufacturing method and type of established form. Nevertheless, analysis method in this study can present the design of friction damper for vibration reduction of cable of cable-stayed bridge from now on.

• Explosives and Blasting
• /
• v.16 no.2
• /
• pp.34-46
• /
• 1998

We developed a method to control vibration from some blasting points. This method uses a correlation of vibration waves to decide the most effective delay time to control vibration by interfering vibration waves with each other. We applied this method to the small blasting using mortar blocks and examined the effect on controlling vibration. As the result of the examinations, the maximum vibration velocity by this method caused by five detonators blasting in row of five holes became smaller than that by a detonator blasting in the nearest hole from the measuring point. And the velocity was about one fifth of that of maximum condition in which vibration waves caused by the five detonators arrivved at the same time to the measuring point.

• Proceedings of the KAIS Fall Conference
• /
• 2010.11b
• /
• pp.551-554
• /
• 2010

유도탄고속함은 우리 해군의 최신예 함정으로서 디젤엔진 2기와 개스터빈 엔진 2기로 구성되어 최대 속력 40노트를 낼 수 있도록 구성되어 있다. 이를 위해 각각의 엔진에는 발전기가 배치되도록 구성되어 있는데, 이러한 발전기는 엔진 및 감속기어가 설치되어 있는 엔진룸에 배치되어 있어 커다란 진동에 그대로 노출이 되어 있는 상황이다. 따라서 이러한 진동의 저감을 위해 이중탄성마운트 등으로 발전기에 전달되는 진동을 저감하고자 하였으나 발전기의 패널에 전달되는 진동의 저감이 불충분하여 패널의 접지 불량이 수차례 발생하였다. 본 연구에서는 이러한 불량을 없애고자 유한요소법을 이용하여 발전기 패널의 위치를 변경하고 구조를 변경하였으며, 이를 통해 그 효과를 검증하였다.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2004.05a
• /
• pp.296-299
• /
• 2004

단열 완충재의 하부단면에서 양각 형태가 전체 면적에서 .차지하는 비율에 따라 진동 충격음 저감량을 실험하였다. 양각 형태가 차지하는 비율이 높더라도 진동 충격음 저감량에는 큰 성능을 나타내지 않았다. 바닥 구조에서 슬래브와 상판 사이에 단열완충재를 설치할 경우 중량 충격음이 오히려 증가하는 경향을 보이고 있다. 이것은 뜬 바닥 구조에서 완충재의 설치로 인하여 슬래브와 상판간의 거동이 다르게 발생하기 때문이다.

• Journal of KSNVE
• /
• v.11 no.1
• /
• pp.96-103
• /
• 2001

Past research has repeatedly demonstrated the fact that hydraulic semiactive systems, if operated Properly, can provide levels of control authority in structural vibration control systems that are comparable to a fully active hydraulic damper. The performance of the semiactive system when used to provide vibration mitigation for a laboratory test structure is described in this paper Numerical and experimental verification of the effectiveness of the proposed bistate controller which relies on a Lyapunov approach that seeks to dissipate the energy of the system is also presented. The results based on the bistate control are compared with those of two different control strategies. The work indicates that hydraulic semiactive actuator provides a reliable, and inexpensive means of achieving structural control.