• 한국자동차공학회논문집
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• 제12권2호
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• pp.148-159
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• 2004

This paper discusses vibration mode of the drivesystem considered the vehicle body's dynamic characteristics to study the influence of the vehicle body's dynamic characteristics on the vibration mode of the engine mount system and the ride quality of a vehicle. The simulation model consists of the engine mount system, the powertrain and the rigid or elastic vehicle body. Variables used in this study are the stiffnesses of an engine mount system and the excitation forces. The Goals of the study are analyzing both the vibration transmitted to the vehicle body including the drivesystem and the influence of the vehicle body's dynamic characteristics on the engine mount system. The mode of drivesystems with a rigid and a elastic vehicle body was compared. From the result of the forced vibration analysis for the drivesystem with a elastic vehicle body, it is shown that the vehicle body's dynamic characteristics influence on the engine mount system reciprocally.

• Ocean and Polar Research
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• 제26권2호
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• pp.323-332
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• 2004

This paper concerns about a study on dynamic responses of tracked vehicle on soft cohesive soil. For dynamic analyses of tracked vehicle, two different models were adopted, i.e. a single-body model and a multi-body model. The single-body vehicle model was assumed as a rigid body with 6-dof. The multi-body vehicle was modeled by using a commercial software, RecurDyn-LM. For the both models properties of cohesive soft soil were modeled by means of three relationships: pressure to sinkage, shear displacement to shear stress, and shear displacement to dynamic sinkage. Traveling performances of the two tracked vehicle models were compared through dynamic analyses in time domain.

• 한국자동차공학회논문집
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• 제6권1호
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• pp.163-181
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• 1998

In this study, the objective is determine the optimal design variable of engine mount system using the rubber mount of bush-type which is usually utilized in passive control to minimize vibrations of vehicle body or transmission from engine into body. The engine model adopted in this study is 4-cylinder, 4-stroke gasoline engine support- ed by 4-points. The system is modelled in 10 d.o.f.-rigid body motion of the engine & transmission in 6 d.o.f., elastic motion of vehicle body in 4 d.o.f.(1st torsional, 1st vertical and 1st & 2nd lateral bending vibration mode). To consider the elastic motion of vehicle body, find the eigenvalues and mode shapes of vehicle body by nodal testing and then determine the modal masses and stiffnesses of the body. The design variables of the engine mount system are locations, stiffness and damping coefficients of the rubber mounts(28 design variables). In case of considering the torque-roll axis for the engine, the design variables of the mount system are reduced to 22 design variables. The objective functions in optimal design process are considered by three cases, that is, 1) transmitted forces through engine mounts, 2) acceleration components of generalized coordinates for the vibration of vehicle body, 3) acceleration of specified location(where gear box) of body. three case are analyzed and compared with each other.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집B
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• pp.459-464
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• 2001

Vibration characteristics of a vehicle are mainly influenced by dynamic stiffness of the vehicle body structure and material and physical properties of the components attached to the vehicle body structure. In this paper, modeling techniques of the vehicle components are presented and the effects of the vehicle components on the vibration characteristics of the vehicle are investigated.

• 한국공작기계학회논문집
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• 제11권2호
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• pp.80-86
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• 2002

Previous method of computer simulation to predict the dynamic response of a vehicle has been based on the assumption that vehicle structure is rigid. If the flexibility of the vehicle structure becomes too large to ignore, rigid body assumption will no longer give good estimation of the dynamic characteristics. Therefore, in order to predict more precise vehicle dynamic characteristics, flexible multi-body dynamic analysis of a vehicle is necessary. This paper investigates dynamic characteristics of vehicle systems with flexible frames numerically. Joint reaction forces, vertical accelerations, pitch accelerations are analyzed for the vehicle systems with various flexible frames using multi-body dynamic analysis code and finite element analysis code.

• International Journal of Automotive Technology
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• 제8권5호
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• pp.629-636
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• 2007

This paper describes the process of analyzing vehicle stiffness in terms of frequency band in order to improve vehicle handling. Vehicle handling and ride comfort are highly related to the systems such as suspension, seat, steering, and the car body design. In existing analytical processes, the resonance frequency of a car body is designed to be greater than 25 Hz in order to increase the stiffness of the body against idle vibration. This paper introduces a method for using a band with a frequency lower than 20 Hz to analyze how stiffness affects vehicle handling. Accordingly, static stiffness analysis of a 1g cornering force was conducted to minimize the deformation of vehicle components derived from a load on parts attached to the suspension. In addition, this technology is capable of achieving better performance than older technology. Analysis of how body attachment stiffness affects the dynamic stiffness of a bushing in the attachment parts of the suspension is expected to lead to improvements with respect to vehicle handling and road noise. The process of developing a car body with a high degree of stiffness, which was accomplished in the preliminary stage of this study, confirms the possibility of improving the stability performance and of designing a lightweight prototype car. These improvements can reduce the time needed to develop better vehicles.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.924-930
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• 2011

Maglev vehicle has two parts a vehicle body and a series of bogies. The vehicle body is connected through a pneumatic suspension on the bogie frame operating loads, vehicle weight and passengers, repeatedly during the service life. The bogie frame plays an important role in sustaining the weight of the vehicle body and controlling the magnets in the correct alignment to meet requirements of stable running on railway. It is also subjected to the levitation and guidance force and propulsion force generated by electromagnets and linear induction motor (LIM) respectively. To guarantee a vehicle system, it is necessary to identify a load test method with proper loads that the vehicle is expected to experience while in service. In this paper, a test method was proposed to verify the structural safety of vehicle body and bogie frame that are applied to an EMS(electromagnetic suspension)-type urban Maglev vehicle considering in case of not only running on the ground but also levitated running.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2002년도 춘계학술강연 및 발표대회
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• pp.7-7
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• 2002

Recently social demand to achieve low fuel consumption and clean emission requires the development of new generation vehicle beyond the conventional vehicle concept. In this point, new generation vehicle is newly designed as electric vehicle, hybrid electric vehicle, fuel cell electric vehicle or 3 liter car etc. In order to develop new generation vehicle, it is very important to develop new materials and process technologies now. In this paper these new technologies are presented focusing on weight reduction specially. Steel body can be achieved 20-25% weight reduction by adoption of high strength steel and new process technologies, i.e tailored blank and hydroforming. Aluminium body can be achieved 40-50% weigt down by use of all aluminium monocoque body or aluminium space frame with aluminium panel. Plasitic composite body can be achieved 30% weight reduction comparing with conventional steel body.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2003년도 춘계학술대회 논문집
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• pp.135-140
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• 2003

This paper is handling about comparative study on dynamic responses of tracked vehicle on soft soil. Two models of tracked vehicle are used in this paper: a single-body model and a multi-body model. Two different methods for dynamic analysis of tracked vehicle are compared: single-body dynamic analysis and multi-body dynamic analysis. Traveling performances of two tracked vehicles are compared.

• 한국자동차공학회논문집
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• 제13권4호
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• pp.121-128
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• 2005

In most researches on the ride comfort analysis of passenger vehicles, the flexibility of the vehicle body has been not considered as an important factor, because the resonance frequencies of the vehicle body related to pitching, yawing and rolling motions are below 10Hz while the resonance frequencies of the vehicle body related to the flexibility are above 20Hz approximately. Nevertheless, the paper shows that the consideration of the local flexibility (or local stiffness) of the 4 corners on which shock absorbers are mounted influences the ride comfort. A simple beam model is devised to qualitatively examine the effect of the change of the local stiffness of the vehicle body on the ride comfort. Based on the results obtained from the analysis of the one-dimensional model, multi-body dynamic analysis considering the flexibility of the vehicle body is performed using ADAMS and MSC/NASTRAN. Natural frequencies and mode shapes computed by MSC/NASTRAN are used as input data for multi-body dynamic analysis in ADAMS. Through simulations using ADAMS, it has been found that the ride comfort can be improved by changing the local stiffness of the vehicle body and that the simulation results agree with experiment results.