• Journal of the Korean Society of Safety
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• v.13 no.4
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• pp.102-112
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• 1998

Shock absorber has a great influence on the performance of the vehicle(ride comfort, manipulation, noise, vibration, turning, stability). Therefore, in this study we consider theoretically about general damper, variable damping oil damper, the control of vehicle Characteristics for the suspension, and undesirable phenomenon. And we measured the vibration/noise characteristics of shock absorber for the real car experimentation, strain change, and noise characteristics of shock absorber using experimental equipment. The study of domestic company and research institute on the vehicle shock absorber is active, but that of basis is not. So we think that they should be accomplished actively. Therefore, this paper will develop theoretical system on the vibration/noise characteristics of shock absorber by theoretical consideration and experimental result analysis of dynamic characteristics of shock absorber that were accomplished in this study. Then we will use it as the optimistic design data for shock absorber development.

• Journal of KSNVE
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• v.9 no.6
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• pp.1166-1172
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• 1999

This paper is the experimental study on the endurance characteristics of the dynamic absorber for the vibration reduction of the 4WD(4 Wheel drive) vehicle's powertrain. Employing the vehicle speed, natural frequencies of damper, modal testing results of powertrain and the weighting factor, the improved endurance test conditions are suggested to enlarge the life time of the dynamic absorber. The test results show that the life time of the dynamic absorber for Z-direction(up and down) has no problems, but the characteristics of X-direction (fore and after) will be sensitive to endurance characteristics of dynamic absorber.

• Geomechanics and Engineering
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• v.36 no.2
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• pp.99-109
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• 2024

Studying the dynamic behavior of axially moving cylindrical shells in hygro-thermal environments has important theoretical and engineering value for aircraft design. Therefore, in this paper, considering hygro-thermal effect, the nonlinear forced vibration of an axially moving cylindrical shell made of functionally graded materials (FGM) is studied. It is assumed that the material properties vary continuously along the thickness and contain pores. The Donnell thin shell theory is used to derive the motion equations of FGM cylindrical shells with hygro-thermal loads. Under the four sides clamped (CCCC) boundary conditions, the Gallekin method and multi-scale method are used for nonlinear analysis. The effects of power law index, porosity coefficient, temperature rise, moisture concentration, axial velocity, prestress, damping and external excitation amplitude on nonlinear forced vibration are explored through parametric research. It can be found that, the changes in temperature and humidity have a significant effect. Increasing in temperature and humidity will cause the resonance position to shift to the left and increase the resonance amplitude.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.14 no.12
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• pp.1249-1254
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• 2004

The road traffic noise becomes aggravated due to the rapid increase of motor vehicles. It has a great effect ell the dwelling environment. We Investigated characteristics and sources of the motor vehicle noise through grasping the status of the motor vehicle noise. Traffic noise results from the collective contribution of the noise produced by individual motor vehicles. The motor vehicle noise varies enormously depending upon its type and mode of operation. This Paper is concerned with the relationship between the vehicle running speed and the noise level under accelerated and steady running.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.05a
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• pp.897-900
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• 2007

Vehicles are exhausting various environmental pollutions such as exhaust gas, noise, and so on. This study investigates only noise problems by vehicles, especially the vehicle exhaust noise. It is known that the exhaust noise among those is over 20% of vehicle noise when the vehicle is suddenly accelerated or normally accelerated. In this study, we mainly investigate the exhaust noise of vehicle so that we intend to show the measures to decrease the illegal tuning mufflers and reduce the exhaust noise problems. In the conclusion, we suggest the new appropriate standard to control the tuning mufflers and reduce the exhaust noise induced by vehicles.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.17 no.12
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• pp.1217-1222
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• 2007

With recent advance in automotive noise control engineering reducing major sound sources in the vehicle, customers perceive Buzz, Squeak and Rattle (BSR) as one of important indicators of vehicle quality and durability. As the long-term goal, we expect to establish the integrated design cycle for the reduction of the BSR noise in the early stage of vehicle development. which consist of design, prediction and evaluation procedures. This is possible only with great bulk of experimental data for BSR noise. In this paper, BSR noise is experimentally identified for vehicle doors, which have been traditionally considered as one of main sources of BSR noise. Based on this result, we proposed systematic method for the prevention of BSR noise in the vehicle doors.

• Transactions of the Korean hydrogen and new energy society
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• v.19 no.4
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• pp.266-275
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• 2008

The performance improvement of each part for durability, safety and cost of high pressure storage system for fuel cell vehicle has been focused so far. However, for the mass production of fuel cell vehicle, it is necessary to evaluate durability and safety in system module and vehicle level. The test procedure to evaluate vibration and collision safety of high pressure hydrogen storage system for the fuel cell vehicle is established and its reliability is verified.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.18 no.12
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• pp.1224-1228
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• 2008

Vehicles are exhausting various environmental pollutions such as exhaust gas, noise, and so on. This study investigates only noise problems by vehicles, especially the vehicle exhaust noise. It is known that the exhaust noise among vehicle noises is over 20% of those when the vehicle is suddenly accelerated or normally accelerated. In this study, we mainly investigate the exhaust noise of vehicle so that we intend to show the measures to decrease the illegal tuning mufflers and reduce the exhaust noise problems. In the conclusion, we suggest the new appropriate standard to control the tuning mufflers and reduce the exhaust noise induced by vehicles.

• Nuclear Engineering and Technology
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• v.54 no.4
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• pp.1355-1362
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• 2022

Nuclear fuel, including its fresh state, must be handled safely due to its critical and hazardous nature. Under normal transport conditions, several interactions take place among different components, such as transport cask used for loading the nuclear fuel and tie-down structure to attach with the vehicle. To ensure structural integrity of the nuclear fuel, vibrations and impacts transmitted from the vehicle must be sufficiently reduced. Therefore, in this study, we conducted two transportation tests from Daejeon to Kijang in Korea to verify the vehicle-induced vibrational characteristics of the KJRR-F fresh nuclear fuel when transported under normal transport conditions. The speed and location of the vehicle were obtained via GPS, and the accelerations between the vehicle and the KJRR-F fresh nuclear fuel were measured. Additionally, using the acceleration results, a structural analysis was conducted to confirm the structural integrity of the nuclear fuel under the most severe conditions during normal transport.

• Wind and Structures
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• v.29 no.5
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• pp.299-312
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• 2019

Due to the rugged terrain, metro lines in mountain city across numerous wide rivers and deep valleys, resulting in instability of high-pier bridge and insecurity of metro train under crosswind. Compared with the conditions of no-wind, crosswind triggers severer vibration of the dynamic system; compared with the short-pier viaduct, the high-pier viaduct has worse stability under crosswind. For these reasons, the running safety of the metro vehicle traveling on a high-pier viaduct under crosswind is analyzed to ensure the safe operation in metro lines in mountain cities. In this paper, a dynamic model of the metro vehicle-track-bridge system under crosswind is established, in which crosswind loads model considering the condition of wind zone are built. After that, the evaluation indices and the calculation parameters have been selected, moreover, the basic characteristics of the dynamic system with high-pier under crosswind are analyzed. On this basis, the response varies with vehicle speed and wind speed are calculated, then the corresponding safety zone is determined. The results indicate that, crosswind triggers drastic vibration to the metro vehicle and high-pier viaduct, which in turn causes running instability of the vehicle. The corresponding safety zone for metro vehicle traveling on the high-pier is proposed, and the metro traffic on the high-pier bridge under crosswind should not exceed the corresponding limited vehicle speed to ensure the running safety.