• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2008년도 춘계학술대회논문집
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• pp.546-550
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• 2008

Impulsive excitation on vehicles produces shock-type vibration on the seat, usually which has major frequencies and damping ratios dependent on the characteristics of the suspension, the tire, the seat cushion and so on. The response of single degree of freedom model to a half-sine force input was considered as simple shock-type vibration signal. The quasi-apparent-mass for fifteen subjects was obtained with the shock-type vibration generated on the rigid seat, so its nonlinearity was found over 6.3 Hz according to the difference of magnitude of the shocks.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2008년도 춘계학술대회논문집
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• pp.613-617
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• 2008

One of the important parts on multimedia era is acoustic ones. With increased demand of smallest multimedia products such as personal digital assistant (PDA) and mobile phones, it is necessary to develop acoustic devices which have higher performance and smaller size. Acoustic parts with various function for hearing impaired persons. This paper introduces a bone conduction vibrator (BCV) for hearing impaired persons to use portable acoustic device without additional devices. For vibration analysis of the BCV, electromagnetic, mechanical and their coupling effects are considered for the analysis. This paper shows that the development of design and analysis technique by finite element method (FEM) of BCV.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 1995년도 추계학술대회논문집; 한국종합전시장, 24 Nov. 1995
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• pp.148-153
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• 1995

저전력소비형 자기부상계로써 영구자석/전자석 조합형 자기부상계에 관한 연구를 수행하였다. 설계에 필요한 여러 고려사항중에서 자기회로 해석, 영구자석의 특성등을 고려한 형상 제원의 설계, 특히 영구자석의 특성 등을 고려한 형상 제원의 설계, 특히 영구자석의 특성과 제원이 동특성에 미치는 영향을 해석하였으며 영구자석/전자석 조합형 자기부상계의 설계에 관한 기초연구를 수행하였다. 1자유도 모형을 이용한 수치예와 실험을 통하여 제시된 방법의 장점인 저전력소비형 자기부상이 가능함을 보였으며 실제 응용예로써 플라이휠용 자기베어링에의 적용 가능성을 수치예를 통해 보였다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2001년도 추계학술대회논문집 I
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• pp.229-234
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• 2001

A practical and effective semi-active on-off control law is developed for vibration attenuation of a natural, multi-degree-of-freedom suspension system, when its operational response mode is available. It does not need the accurate system parameters and dynamics of semi-active actuator. It reduces the total vibratory energy of the system including the work done by external disturbances and the maximum energy dissipation direction of the semi-active control device is tuned to the operational response mode of the structure. The effectiveness of the control law is illustrated with a three degree-of-freedom excavator cabin model.

• 한국소음진동공학회논문집
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• 제12권1호
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• pp.29-35
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• 2002

A simulation program for vehicle dynamic analysis was developed. The Cartesisn coordinate system was used for translational motion and the Euler angle system was used for rotational motion. A three dimensional multi-wheeled vehicle model and equations of motion were derived. Also static equilibrium analysis was added for initial vehicle condition setting. The program user can describe the exact characteristics of suspension spring force and damping force in the user subroutine. A wheel-ground contact model which represents geometrical effect was developed. Two cases of simulation for 16 D.O.F. vehicle model were conducted to validate the developed program by comparing the simulation results with the experimental data.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 춘계학술대회논문집
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• pp.378-383
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• 2004

Bogie is the connection device between carbody and wheel. It is the core part that exert a important effect on the passenger safety and running safety. Bogie largely consist of bogie frame, suspension, brake, wheel set. Static and Dynamic load have acted on it complexly. So when the bogie is designed, finite element method, static load test, fatigue test running test should be considered. Some bogie frame of high speed railway freight car have the problem. It's end beam was cracked. The crack of the end beam have a bad effect on brake system. ROTEM co. made an improved end beam and applied one set to freight car. this report showed the vibration characteristic which was compared conventional bogie to improved bogie for running safety.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2000년도 춘계학술대회논문집
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• pp.1338-1343
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• 2000

This paper deals with an application of Magneto-Rheological (MR) fluid to a small size mount for precision equipment of automobiles. MR fluid is known as a class of functional fluids with controllable apparent viscosity of fluid by the applied magnetic field strength. A typical MR fluid is a suspension where pure iron particles of $1{\sim}20mm$ in diameter are dispersed in a liquid such as mineral oil or silicone oil, at the concentration of $20{\sim}40$ vol%. Electro magnetic coil is installed at the bottom of a variable-damping mount filled with MR fluid, and its performance was investigated experimentally. Furthermore, the properties of the MR Mount on experimental Study were explained analytically by mechanical model of the MR mount.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2000년도 춘계학술대회논문집
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• pp.900-910
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• 2000

This study have been performed to investigate the dynamic behavior of the Korean High Speed Train(KHST) during the conceptual design process. This study gets a focus on the analysis of the rigid model, for which the yaw damper layout is modified in a nonlinear limit cycle analysis. In this study, influences of the system parameters such as stiffness of suspension and connection elements as well as damping coefficients were studied and an optimized parameter set is achieved. Throughout the dynamic calculation of KHST on the straight and the curved track, vibration accelerations in car body, ride comforts and wheel rail forces are investigated. Finally the vibration characteristics from rigid car body are compared with those due to the influence of elastic car body.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2000년도 춘계학술대회논문집
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• pp.894-899
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• 2000

Optimization of 26 design variables selected from suspension characteristics for Korean High Speed Train (KHST) is performed according to the minimization of 58 responses which represent running safety and ride comfort for KHST and analyzed by using the each response surface model from stochastic design experiments. Sensitivity of design variables is also analyzed through the response surface model which ineffective design prameters to the performance index are screened by using stepwise regression method. The response surface models are used for optimizing design variables through simplex algorism. Values of performance index simulated by optimized design parameters are totally lower than those by initial design parameters. It shows that this method is effective for optimizing multi-design variables to multi-object function.

• 한국소음진동공학회논문집
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• 제18권7호
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• pp.732-740
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• 2008

This paper presents vibration control performances and stability evaluations of railway vehicle featuring controllable magnetorheological(MR) damper. The MR damper model is developed and then incorporated with the governing equations of motion of the railway vehicle which includes vehicle body, bogie and wheel-set. A cylindrical type of MR damper is devised and its damping force is evaluated by considering fluid viscosity and MR effect Design parameters are determined to achieve desired damping force level applicable to real railway vehicle. Subsequently, computer simulation of vibration control and stability analysis is performed using Matlab Simulink.