• 한국자동차공학회논문집
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• 제15권6호
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• pp.177-182
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• 2007

In this paper, automotive hydraulic pipeline systems are modeled in which a straight blocked pipe, two pipes with sudden expansion or contraction are connected in series and terminated with a chamber. The frequency response characteristics of these composite pipeline systems are investigated experimentally. The theoretical analysis for various pipe configurations is base on transfer matrix method with frequency dependent viscous friction distributed parameter pipeline model. The gain and phase of transfer functions are included for comparison with experimental results. There is close agreement between the results of experimental and theoretical determination of pressure response in automotive hydraulic pipeline systems.

• 대한안전경영과학회지
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• 제15권1호
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• pp.41-49
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• 2013

This paper reviewed the relationship among job characteristics, psychological stress response, and accidents, and the mediating effect of psychological stress response between job characteristics and accidents. Based on the responses from 176 employees, the results of multiple regression analysis appeared as follow; 1) autonomy, importance and feedback effect negatively on psychological stress response. 2) psychological stress response effects positively on accident frequency. 3) psychological stress response mediates fully between autonomy and accident. 4) psychological stress response mediates partly between feedback and accident.

• Earthquakes and Structures
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• 제4권2호
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• pp.181-202
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• 2013

It is well known that the properties of the soil deposits, especially the damping, depend on both frequency and strain amplitude. Therefore it is important to consider both dependencies to calculate the soil response against earthquakes in order to estimate input motions to buildings. However, it has been difficult to calculate the seismic response of the soil considering both dependencies directly. The author has studied the time domain evaluation of the frequency dependent dynamic stiffness, and proposed a simple hysteretic damping model that satisfies the causality condition. In this paper, this model was applied to nonlinear analyses considering the effects of the strain amplitude dependency of the soil. The basic characteristics of the proposed method were studied using a two layered soil model. The response behavior was compared with the conventional model e.g. the Ramberg-Osgood model and the SHAKE model. The characteristics of the proposed model were studied with regard to the effects of element divisions and the frequency dependency that is a key feature of the model. The efficiency of the model was confirmed by these studies.

• Journal of Theoretical and Applied Mechanics
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• 제3권1호
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• pp.34-44
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• 2002

Theoretical analysis Is carried out to identify the modal coupling effect between some particular acoustic modes of a vehicle compartment cavity and vibration modes of body panels like side doors, roof or floor. A simplified panel-cavity coupled model is investigated on the coupled resonance frequencies, modes and frequency response characteristics. Through parametric study, It Is possible to explain how the acoustic response of a coupled system will be determined by the vibration and acoustic property of the individual panel and cavity system. Full coupled system shows some interesting features different from those of the semi-coupled system In frequency, mode and acoustic response.

• 전산구조공학
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• 제9권4호
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• pp.107-115
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• 1996

변위응답은 교량구조의 진동특성을 결정하는데 중요한 인자 중의 하나이다. 계측된 가속도 데이타를 진동수 영역에서 적분하여 변위응답을 경제적이고 합리적으로 구할 수 있다. 이를 위해 계측된 가속도 데이타를 이산화하기 위해 적절한 표본추출 진동수가 제시되었다. 캔틸레버 보를 이용한 실내시험에서 직접 계측된 변위와 적분된 변위는 서로 잘 일치하였다. 평가된 변위응답으로부터 구한 모우드 형상도 해석치와 근접하므로 개발된 방법은 실제로 효율적으로 사용될 수 있음을 입증하였다.

• 한국소음진동공학회논문집
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• 제13권11호
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• pp.868-874
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• 2003

A nonlinear modeling method for an axially oscillating cantilever beam with a concentrated mass is presented in this paper. Hybrid deformation variables are employed for the modeling method with which frequency response characteristics of axially oscillating cantilever beams are investigated. The geometric nonlinear effects of stretching and curvature are considered to accurately predict the frequency response characteristics of the oscillating cantilever beam. The effects of the size and the location of the concentrated mass on the frequency characteristics are investigated. It is found that the dynamic instability is significantly influenced by the two parameters.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 추계학술대회논문집
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• pp.1134-1139
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• 2007

In recent years, public complaints about railroad noise by KTX and Ordinary train are increasing. Restriction of railways uses same standard without distinguishing the type of railways. According to the type of railways, the frequency characteristics of emitting noise is different. Therefore it is requested to know how vary the public response to each types of railway. The noise annoyance to three types of trains (KTX, Electric train, Diesel train) was analyzed by Jury Evaluation Test for assessing the effect of frequency characteristics. The numerical results by a Semantic Differential Method showed that annoyance response to three type of trains depended on the frequency characteristics. As a result, this study proposed that the KTX could have a bonus level of maximum 2.9dB(A) to ordinary train.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2003년도 춘계학술대회논문집
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• pp.477-482
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• 2003

A nonlinear modeling method for an axially oscillating cantilever beam with a concentrated mass is presented in this paper. Hybrid deformation variables are employed fur the modeling method with which frequency response characteristics of axially oscillating cantilever beams are investigated. The geometric nonlinear effects of stretching and curvature are considered to accurately predict the frequency response characteristics of the oscillating cantilever beam. The effects of the magnitude and the location on the concentrated mass on the frequency characteristics are investigated. It is found that the dynamic instability is significantly influenced by the two parameters.

• 대한기계학회논문집
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• 제18권11호
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• pp.3075-3083
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• 1994

The applications of the electrical transmission line theory to the pressure propagation characteristics in the volume loaded fluid transmission line with step and impulse input wave is demonstrated in this paper. The method is based on the premise that the time response is the inverse Fourier transform of frequency spectrum of the wave which spectrum is a product of frequency spectrum of input pressure wave and system transfer function. The frequency response and transient response of step and impulse input wave in the volume loaded fluid transmission line is analysed by the Laplace transform and inverse Laplace transform with FFT numerical algorithm. The numerical solution of the distributed friction model is compared with the average friction model and the infinite product model. And the result is showed that FFT method may have major advantages for the simulation of fluid circuitary.

• 한국소음진동공학회논문집
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• 제14권9호
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• pp.897-902
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• 2004

In this paper, a vibration endurance test is performed on rubber insulators used for vehicle air cleaners. Based on the test results, the endurance characteristics depending on the type and the material of the insulators are estimated. The frequency response characteristics of the air cleaner system including the insulator are investigated to identify the cause of wear and failure of the insulator. New insulator models with improved endurance characteristics are proposed and tested. Test results show that the vibration endurance property of the insulator is strongly dependent on the frequency response characteristics of the air cleaner system as well as the deformed shape of the insulator.