• Proceedings of the Computational Structural Engineering Institute Conference
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• 2000.04b
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• pp.230-237
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• 2000

The purpose of this study is to evaluate the dynamic behavior of highway bridge due to moving vehicle load, considering the effect of laminated rubber bearing. Dynamic behaviors of bridge considering the effect of bearings are studied with 3-dimensional bridge and vehicle models. To analyze the effect of bearings on the dynamic behaviors of superstructures of bridges, laminated rubber bearing is modeled as 3-dimensional frame element with equivalent stiffness and damping, and the models are included in the bridge analysis model. The results from the analytical models with laminated rubber bearing show a significant effects on dynamic responses and more complex vibration characteristics compared with the results from the bridge with pot bearings. Generally, larger dynamic amplification factors are obtained in the case of laminated rubber bearing, which is mainly due to the smaller torsional stiffness of the bridge with laminated rubber bearing. It can be recommended that were careful consideration on the vibration of bridges and dynamic load allowance in design are needed when adopting laminated rubber bearing.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.19 no.1
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• pp.71-79
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• 2010

One of methods that accomplish fuel-efficient vehicle is to reduce the overall vehicle weight by using aluminum structure typically for cross members, rails and panels in body and chassis. For aluminum structures, the use of Self Piercing Rivet(SPR) is a relatively new joining technique in automotive manufacture. To predict SPR fatigue life, fatigue behavior of SPR connections needs to be investigated experimentally and numerically. Tests and simulations on lap-shear specimen with various material combinations are performed to obtain the joining strength and the fatigue life of SPR connections. A Finite element model of the SPR specimen is developed by using a FEMFAT SPR pre-processor. The fatigue lives of SPR specimens with the curvature are predicted using a FEMFAT 4.4e based on the liner finite element analysis.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.9 no.3
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• pp.19-27
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• 2010

Cylinder block is driven by tapered piston for bent-axis type piston pump, so that geometrical mechanism is very complicate. Piston rod must have not separated from shaft when shaft and piston rod is assembled. For this reason, shaft design is changed. Finite element analysis is performed for analyzed structural stability and flexible dynamic behavior. The result of the analysis, maximum equivalent stress occurred under yield stress, therefore structural stability is satisfactory. and flexible dynamic analysis give useful information about driving gear. These background data is avail of manufacture of piston pump.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.05a
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• pp.356-360
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• 2007

Fuel sloshing in a vehicle fuel tank generates a reluctant low frequency noise, called slosh noise. To reduce slosh noise, whilst many approaches have used the Computational Fluid Dynamics method to first identify fuel behavior in a fuel tank, this paper applies the Transfer Path Analysis method. It is to find contribution of each transfer path from noise transfer function, vibration transfer function and acceleration. Then the final goal is to attenuate slosh noise by controlling them. To this aim, two types of models are studied. One is the decoupled model in which some of connection points of the fuel tank with the vehicle underbody are separated. The other is the modified model which is created by changing noise transfer function and acceleration from the original model. The analysis and validation test results show that the transfer path analysis can be an approach to enhancing slosh noise.

• Transactions of the Korean Society of Automotive Engineers
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• v.12 no.3
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• pp.170-176
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• 2004

MR dampers show highly nonlinear and histeretic dynamic behavior. Therefore, for a vehicle dynamic simulation with MR dampers, this dynamic characteristics should be accurately reflected in the damper model. In this paper, an artificial neural network technique was developed for modeling MR dampers. This MR damper model was successfully verified through a random input forcing test. This MR damper model can be used for semi-active suspension vehicle dynamics and control simulations with practical accuracy.

• Transactions of the Korean Society of Automotive Engineers
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• v.10 no.4
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• pp.199-205
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• 2002

This paper presents a numerical technique to analyze wear life of automotive disk brake pad, where FFT-FEM method is adopted to determine the transient temperature distribution of the disk surface. A specimen ova frictional material is tested on a small scale brake dynamometer to find the dependency of the wear rate on temperature change, from which and the temperature analysis results, given the wear test mode, wear behavior of the pad material fur the vehicle can be predicted. Numerical examples show the predicted wear life of the vehicle coincides with the manufacture's recommended time interval for replacing the pads.

• Transactions of the Korean Society of Automotive Engineers
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• v.15 no.5
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• pp.48-55
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• 2007

A bushing component of a vehicle suspension system is tested to capture the nonlinear behavior of rubber bushing element using the MTS 3-axes rubber test machine. The results of the tests are used to model the artificial neural network bushing model. The performances from the neural network model usually are dependent on the structure of the neural network. In this paper, maximum error, peak error, root mean square error, and error-to-signal ratio are employed to evaluate the performances of the neural network bushing model. A simple simulation is carried out to show the usefulness of the developed procedure.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2002.04a
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• pp.10-13
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• 2002

Pogo is the instability resulting from the interaction between rocket structure and propulsion system of liquid propellant rocket. The coupling of structure and propulsion system can lead to severe problem in rocket. For the analysis of pogo, a time-invariant linearized mathematical model is developed for a selected flight time. Propulsion system is modeled using element representations for each components. The constitutive equation of propulsion system is a homogeneous second-order equation form in the Laplace domain. Rocket structure is modeled using FEM. From the results of modal analysis of structure, the behavior of structure can be represented. System equations for coupling structure and propulsion system are composed of all propulsion system equations and vehicle motion equations reacting on the vehicle by each component of propulsion system. The stability is obtained by the eigen solution of system matrix. The optimization of the design variables such as size, place of accumulator for suppressing pogo instability is carried out. This article of study can be used to determine the degree of stability, and guide the design of pogo suppression system.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.11 no.1
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• pp.70-76
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• 2002

Unmanned vehicles have to decide their velocities suitable for the paths which should be generated by the vehicles themselves, based on the kinematic and dynamic aspects of vehicles. For this purpose, this paper is to propose a mathematical modeling of tuning trace for the cornering of an unmanned vehicle by using normal-tangent coordinates as well as extracting the characteristics of behavior for car drivers in cornering. In the proposed modeling, the limitations of velocity can be determined based on the knowledge that the handling of drivers means the control of radius of curvature. The proposed modeling can reduce computational load and generate turning angles and velocities suitable for the cornering of unmanned vehicles.

• 한국전산유체공학회:학술대회논문집
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• 2006.10a
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• pp.142-146
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• 2006

The behavior of a hemisphere-cylinder flight vehicle at high angles of attack and side slip angles have been studied. $0^{\circ}{\sim}35^{\circ}$ angles of attack and $0^{\circ}{\sim}5^{\circ}$ side slip angles were selected as fright conditions at Mach No. 0.3. Flow changes from low angles of attack to high angles of attack were compared and analyzed. We changed from low to high angles of attack with small side slip angles. We compared normal, side and axial force coefficients among various test cases.