• 동력기계공학회지
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• 제11권2호
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• pp.32-37
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• 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 3 men and 3 women. 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.

• 동력기계공학회지
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• 제14권4호
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• pp.29-36
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• 2010

인체에 음향진동장치에 의하여 자극을 가하였을 경우 영향을 고찰한다. 5명의 건강한 남자 대학생을 대상으로 하여, 3가지 형태의 음악을 음향과 진동자극의 신호원으로 사용해서 실험을 행하였다. 모든 피험자에 대하여, 자극 전, 음악자극, 진동자극, 자극 후로 나누어 뇌파를 측정하였다. 실험의 모든 피험자의 측정 데이터의 t-검정을 수행하여 유의성이 있는 데이터에 한하여 뇌파를 고찰하였다. 결과로서, 음악과 음향파와 진동자극이 뇌파에 미치는 영향은 음향진동장치에 따른 진동자극 형태, 피험자의 몸과 정신 상태에 따라 현저하게 달라질 수 있다는 것을 알 수 있다. 그리고 적절한 음악과 음향진동장치를 사용하여 특정의 뇌파 상태를 유도 할 수 있음을 확인하였다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 추계학술대회논문집
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• pp.644-647
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• 2007

In this paper, we present our method of controlling the transmission path of compressor vibration to reduce the vibroacoustic of refrigerator. Firstly, to reduce the vibroacoustic radiated from compressor _ mount system, main transmission path was found experimentally and applied partial contact to transmission path to minimize the transmissibility from compressor operation to base plate. In order to verify our method, we designed changing of the connection part between grommet and base plate. Through experiment with modified connection part, we certificate experimentally the noise reduction of refrigerator. Finally, we apply previous connection part to grommet inner shape to enhance the effect of the system. From experimental results, we make certain the possibility of noise reduction of refrigerator through this approach.

• 한국항공우주학회지
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• 제34권2호
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• pp.82-89
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• 2006

항공기의 플러터 및 진동소음 특성은 장기간에 걸친 다양한 비행시험을 통해서만 획득 가능하며, 생성된 방대한 양의 데이터를 효율적으로 축적하기 위해서는 특별히 설계된 데이터베이스 시스템이 필요하다. 이에 따라 MS-Access를 기반으로 하여 T-50 고등훈련기 비행시험 시 측정된 플러터/진동소음 환경 데이터를 처리하는 데이터베이스 시스템을 개발하였다. 개발된 시스템은 항공기 비행시험과 관련된 자료 항목, 관련 항목으로 구성된 테이블, 그리고 작성된 테이블들을 논리적으로 연결한 관계형 데이터베이스로 구성되며, 비쥬얼 베이직과 구조적 질의어를 이용한 데이터 검색 GUI(Graphic User Interface)를 구현하여 직관적인 검색이 가능하도록 되어 있다. 개발된 시스템을 이용하여 플러터/진동소음 데이터의 축적 및 요구도 검증에 효과적으로 활용하였다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 1996년도 추계학술대회논문집; 한국과학기술회관, 8 Nov. 1996
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• pp.135-141
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• 1996

Numerical analysis techniques have been applied to obtain the vibroacoustic characteristics of the simplified model of a passenger-car cabin. Two kinds of coupled vibration-acoustic analysis, such as one-way coupling and full coupling, have been carried out via the interface between the results of vibration analysis by FEM and acoustic analysis by BEM. The comparison of two coupled analysis results show the fluid-structure interaction in terms of the coupled effect of the vibration and noise.

• 동력기계공학회지
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• 제12권5호
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• pp.59-64
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• 2008

이 연구는 음악과 음향진동자극이 인체의 생리적 변화 즉 특정 뇌파발생의 유도에 미치는 영향을 실험적으로 고찰한 결과 다음과 같이 요약할 수 있다. 1. 음악자극만의 경우보다 음향진동자극을 동시에 가하였을 경우가 특정뇌파상태로의 유도가 용이하고 현저하였다. 2. 자극2와 자극5의 자극에 사용된 음악은 이완작용 및 스트레스해소에 적합한 음악이다. 3. 자극6의 음악은 스트레스가 없고 정신집중상태에서 많이 발생하는 SMR파의 유도에 효과가 있을 것으로 생각된다.

• 한국정밀공학회지
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• 제28권10호
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• pp.1196-1203
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• 2011

Statistical optimum methodology of table of orthogonal array, ANOM, ANOVA and RSM are applied to formulate optimum allocation design with design variables. It can be minimized average SPL of control volume, the objective function in closed system by optimal allocated positions of absorbing material. Structural natural frequency and acoustic natural frequency of cavity are analyzed by FEM and BEM in the closed system. Using BEM, average SPL of specific control volume is calculated according to the condition before using absorbing material and after using it. It is shown that noise is reduced by $5.02dB_{RMS}$ by absorbing material located at optimal position and minimum $1.83dB_{RMS}$ and maximum $3.47dB_{RMS}$ by the table of orthogonal array.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2000년도 춘계학술대회논문집
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• pp.325-333
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• 2000

To predict vibrational energy density and intensity of partitioned complex system structures in medium-to-high frequency ranges, Power Flow Finite Element Method(PFFEM) programs for the plate elements are developed. The flexural, longitudinal and shear waves in plates are formulated and the joint element equations for multi-couped plates are fully developed. Also the wave transmission approach has been introduced to cover the energy transmission and reflection at the joint plate elements. Using the developed PFFEM program the energy density and intensity of the submarine and automobile shape structures are predicted with a harmonic point force at a single frequency.

• 한국자동차공학회논문집
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• 제9권2호
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• pp.168-175
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• 2001

Reduction of structure-borne noise of the compartment in a car is an important task in automotive engineering. Transfer path analysis using vibroacoustic reciprocity technique or multiple path decomposition method has generally been used for structure-borne noise path analysis. These methods are useful in solving particular problem but do net quantify the effectiveness of vibration isolation of each isolator of a vehicle. To quantify the effectiveness of vibration isolation, the vibrational power flow has been used for a simple isolation system or a laboratory based isolation system. It is often difficult to apply the vibrational power flow technique to the complex isolation system like a car. In this paper, a simple equation is derived for calculation of the vibrational power flow of an isolation system with multiple isolators such as a car. It is successfully applied to not only quantifying the relative contributions of eighteen isolators but also reducing structure-borne noise of a passenger car. According to the results, the main contributor of eighteen isolators is the rear roll mount of an engine. The reduced structure-borne noise level is about 5dBA.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2000년도 추계학술대회논문집
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• pp.208-214
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• 2000

Reduction of structure-borne noise of the compartment in a car is an important task in automotive engineering. Transfer path analysis using vibroacoustic reciprocity technique or multiple path decomposition method has generally been used for structure-borne noise path analysis. These methods are useful in solving particular problem but do not quantify the effectiveness of vibration isolation of each isolator of a vehicle. To quantify the effectiveness of vibration isolation, the vibrational power flow has been used for a simple isolation system or a laboratory based isolation system. It is often difficult to apply the vibrational power flow technique to the complex isolation system like a car. In this paper, a simple equation is derived for calculation of the vibrational power flow of an isolation system with multiple isolators such as a car. It is successfully applied to not only quantifying the relative contributions of eighteen isolators but also reducing structure-borne noise of a passenger car. According to the results, the main contributor of eighteen isolators is the rear roll mount of an engine. The reduced structure-borne noise level is about 5dBA.