• Transactions of the Korean Society of Automotive Engineers
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• v.16 no.4
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• pp.97-102
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• 2008

The vibration of a vehicle, which is caused by and transmitted from the engine, has significant effect on the ride comfort and the dynamic characteristics of the engine mount system have direct influence on the vibration and noise of the vehicle. This paper examines the body shake caused by the engine excitation force on engine key on/off of a medium truck by experiment and simulation. The analysis model consists of the engine, a body including the frame, front and rear suspensions and tires. The force element between the body and the suspension is modeled as a combination of a suspension spring and a damper. The engine shake obtained from the experiment was compared with the result of the computer simulation, and by using the verified computer model, parametric study of the body shake on engine key on/off is performed with changing the stiffness of an engine mount rubber, the engine mount angle, and the position of engine mounts.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1997.04a
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• pp.336-342
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• 1997

In this paper, in order to analyze dynamic characteristics of automobile steering system consisting of many components, natural frequencies and transfer functions of each component and total system are found on FFT by experiments. Then, the data are transmitted to commercial package program, CADA-PC. By analyzing the data, the mode shape of each natural frequency and damping values are obtained. Also, the function of rubber coupling in column and telescoping effects on system are considered. C.A.E commercial program are used to compare with the results of experiments. For finite element modeling, I-DEAS is used. Data processing and post processing are operated on NASTRAN and XL, respectively. The ball-bearing and the linkage of shaft with column are modeled by spring elements. Stiffness is modified from the results of experiments. The results of those show close agreement. In the mode shape of total system, wheel mode is dominant at lower frequency while the column mode is main mode at higher . The role of rubber coupling in vibration isolation is clear on mode shape. Telescoping function makes natural frequency of column changed.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.20 no.3
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• pp.371-377
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• 2007

In this paper, acceleration threshold of perception for the horizontal vibration of tall buildings was estimated. Excessive vibration of tall buildings by wind can give displeasure, such as giddiness and visual insecurity. To provide comfortable environment to residents of tall buildings, acceleration needs to be limited. For tall buildings the first mode of vibration is dominant. To reproduce the first mode of vibration, experiments were performed by generating sine waves by a shaking table. A nitration house was made and forty persons were employed for experiments. The forty persons were organized into five experimental groups, each of which was composed of eight persons, and the threshold of perception for horizontal vibration was measured by increasing acceleration in the range of 0.2Hz through 1.2Hz of frequency, Performance curves were obtained by dividing the distribution of perception for horizontal vibration into the range of $0{\sim}20%,\;21{\sim}40%,\;41{\sim}60%,\;61{\sim}80%\;and\;81{\sim}100%$ and by fitting curves.

• International Journal of High-Rise Buildings
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• v.11 no.4
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• pp.347-362
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• 2022

Current vibration serviceability assessment criteria for wind-induced vibrations in tall buildings are based largely on human 'perception' thresholds which are shown not to be directly translatable to human 'acceptability' of vibrations. There is also a considerable debate about both the metrics and criteria for vibration acceptability, such as frequency of occurrence or peak vs mean vibration, and how these might vary with the nature of the vibration. Furthermore, the design criteria are necessarily simplified for ease of application so cannot account for a range of environmental, situational and human factors that may enhance or diminish the impact of vibrations on serviceability. The dual-site VSimulators facility was created specifically to provide an experimental platform to address gaps in understanding of human response to building vibration. This paper considers how VSimulators can be used to inform general design guidance and support design of specific buildings for habitability, in terms of vibration, which allow engineers and clients to make informed decisions with regard to sustainable design, in terms of energy and financial cost. This paper first provides a brief overview of current vibration serviceability assessment guidelines, and the current understanding and limitations of occupants' acceptability of wind-induced motion in tall buildings. It then describes how the dual-site VSimulators facility at the Universities of Bath and Exeter can be used to assess the effects of motion and environment on human comfort, wellbeing and productivity with examples of how the facility capabilities have been used to provide new, human experience based experimental research approaches.

• Proceedings of the KSR Conference
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• 1998.05a
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• pp.494-501
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• 1998

This Paper describes the evaluation methods and criteria used to verify running Performance of railway vehicle, and shows results of vehicle dynamics simulation and running performance tests for New Mugunghwa Coaches that were designed and manufactured by DHI in 1997. Through running performance test of New Mugunghwa Coaches, Vibration, Ride Comfort were measured on the condition of service operation. As a results, each simulation and test results meet the criteria proposed by Korean National Railroad(KNR) and Korea Railroad Research Institute(KRRI).

• Proceedings of the KSR Conference
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• 2003.05a
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• pp.730-733
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• 2003

In this study, it have been measured the vertical and lateral vibrations of car bodies which have an equivalent conicity of 1/20 and 1/40. Based on the measured data, it is revealed that the wheel, XP-50, which has the equivalent conicity of 1/20 causes the better riding comfort of KTX.

• International Journal of High-Rise Buildings
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• v.10 no.3
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• pp.165-171
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• 2021

Core-outrigger-mega frame system is used in Suzhou IFS with 95-story, 450 m-tall, which is beyond Chinese code limit. Besides simple introduction on design principle, structure system and analysis, key techniques including performance based design criteria, frame shear ratio, capacity check of mega column, human comfort criteria under wind induced vibration and TSD design were presented in details for reference of similar super tall building design.

• Journal of the Korean Society for Railway
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• v.15 no.1
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• pp.48-61
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• 2012

It is of great importance to assure the running safety, ride comfort and serviceability in designing the floating slab track for mitigation of train-induced vibration. In this paper, for this, analyzed are the system requirements for the running safety, ride comfort and serviceability, and then, the behavior of train and track at the floating slab track including the transition zone to the conventional concrete slab track according to several main design variables such as system natural frequency, arrangement of spring at transition, spacing of spring isolators, damping ratio and train speed, using the dynamic analysis technique considering the train-track interaction. The results of this study demonstrate that the discontinuity of the support stiffness at the transition results in a drastic increase of the dynamic response such as wheel-rail interaction force, rail bending stress and rail uplift force. Hence, it is efficient to decrease the spacing of springs or to increase the spring constants at the transition to obtain the running safety and serviceability. On the other hand, the vehicle body acceleration as a measure of ride comfort is little affected by the discontinuity of the stiffness at the transition, but by the system tuning frequency; thus, to obtain the ride comfort, it is of great significance to select the appropriate system tuning frequency. In addition, the effects of damping ratio, spacing of springs and train speed on the dynamic behavior of the system have been discussed.

• Journal of Mechanical Science and Technology
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• v.20 no.9
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• pp.1346-1354
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• 2006

Excessive acceleration experienced at the top floors in a building during wind storms affect the serviceability of the building with respect to occupant comfort and discomfort. Tuned liquid damper (TLD) and multiple tuned liquid damper (MTLD), which are passive control devices consisting of a rigid tank filled with liquid, are used to suppress vibration of structures. These TLD and MTLD offer several potential advantages-low costs, easy installation in existing structures and effectiveness even for small-amplitude vibrations. This study carries out a theoretical estimation of the most effective damping ratios that can be achieved by TLD and MTLD. Damping by TLD an MTLD reduced the frequency response of high-rise buildings by approximately 40% in urban and suburban areas.

• Proceedings of the KSR Conference
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• 2011.05a
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• pp.61-69
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• 2011

The noise and vibration which are occurred by equipment and rail under the train are directly delivered to passenger and effect on comfort. For this reason, Floating floor structure has been applied to Rolling Sotck for minimizing the noise and vibration. And in respect of Floating floor, the strength is an important design element. Because the train has many heavy equipments and accommodates lots of passenger. At the early design stage of Floating floor, different joint type and thickness of plywood, etc. were applied and some problem happened. To solve the problems and apply to the future projects, the standard model of Floating floor structure was required. To find optimum design and standard model for Floating floor structure of Rolling Stock, the applied Floating floor models were analysed by CAE (computer-aided engineering).