• 한국자동차공학회논문집
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• 제10권6호
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• pp.166-170
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• 2002

A hybrid structure composed of magnesium and steel is Instrument Panel structure used for the basement of cockpit module components. For that reason, A hybrid structure has to be designed for satisfying components assembly design facility and styling. There are various models of If like steel structure assembly, however having been applied normally, but magnesium structure assembly selected far saving weight down. This paper introduces a hybrid structure having advantages between steel and magnesium structure and presents a CAE technical solution based on a development project. furthermore, it provides desired direction of the future development is suggested.

• International Journal of Automotive Technology
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• 제5권3호
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• pp.189-194
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• 2004

The viscoelastic layer material is widely used to control the noise and vibration characteristics of the panel structure. This paper describes the design technology of the effective vibration damping treatment using the concept of the equivalent parameter of viscoelastic layer materials. Applying the equivalent parameter concepts based on theories of shell, it is possible to simulate the finite element analysis of damping layer panel treatments on the vibration characteristics of the structure. And it is achieved the reduced computational cost and the optimal design of topological distribution for the reduction of vibration effect.

• 한국자동차공학회논문집
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• 제12권5호
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• pp.101-107
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• 2004

Recently the objective of vehicle design was focused on the crash safety and the energy saving. For the energy saving vehicle structures must be light weight, but for the crash safety some energy absorbing elements must be added. In this paper hybrid structure which consists of a steel and a FRP was studied on the energy absorption characteristics under the impact load by finite element method. Test results of the other researchers were compared with that of computer simulation on this simple hybrid structure. Side rail of vehicle front structure was replaced with hybrid materials for the application of the vehicle structure. 35mph frontal crash simulation was performed with hybrid structure and with conventional steel structure. By the adoption of hybrid structure, the improvement of energy absorption characteristics and reduction of weight was observed under the frontal crash simulation.

• 열처리공학회지
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• 제23권6호
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• pp.301-308
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• 2010

A steel with chemical composition, 0.22% C, 0.25% Si, 1.26% Mn, 0.22% Cr, 0.04% Ti, 0.0042% B, and a microstructure of ferrite and spheroidized cementite has been press-formed to automotive center pillar followed by local-hardening heat-treatment. Hardness, tensile properties, fractography, microstructure and surface roughness of local-hardening heat-treated automotive center pillar have been examined. The directly heated and quenched area had fully martensitic structure with Vickers hardenss in the range of 500 to 510. The heat affected area close to the directly heated area showed dual-phase structure of ferrite and martensite. The width of the heat-treated and heat-affected areas after the local-hardening heat treatment was ranging from 32 mm to 50 mm. The surface of the local-hardening heat-treated center pillar revealed some temper color as a consequence of the oxidation during the heat treatment, but the surface roughness was not affected by the local-hardening heat treatment.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.382-385
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• 2003

In this paper, in order to improve the control performance of piezoelectric actuator, an integrated control structure is proposed. The control structure consists of inverse hysteresis model , to compensate the hysteresis nonlinearty problem, and feedforward - feedback controller to give a good tracking performance. The inverse hysteresis model and neural network are used as feed-forward controller, and PID controller is used as a feedback controller. From diverse experiments it is concluded that the proposed control scheme gives good tracking performance than the classical control does.

• 한국자동차공학회논문집
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• 제10권1호
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• pp.125-132
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• 2002

Recently, ULSAB(Ultra Light Steel Auto Body) concept is getting more attention due to various benefits in automotive body design. One of the ULSAB efforts is making a door with TWB(Tailor Welded Blanks). In TWB, two or more patches of steel panels are welded together before stamping process. In this research, domains and thicknesses of the patches in a front door structure are determined by a series of optimization schemes composed of topology, size and shape optimization and DOE(Design of Experiments) scheme. A door is designed to have better performances compared to exiting structure considering static stiffness and natural frequency. The final design is discussed and compared to the existing design.

• International Journal of Automotive Technology
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• 제4권3호
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• pp.135-140
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• 2003

In the deterministic optimization of a structural system, objective function, design constraints and design variables, are treated in a nonstatistical fashion. However, such deterministic engineering optimization tends to promote the structural system with lest reliability redundancy than obtained with conventional design procedures using the factor of safety. Consequently, deterministic optimized structures will usually have higher failure probabilities than unoptimized structures. Therefore, a balance must be developed between the satisfactions of the design requirements and the objectives of reducing manufacturing cost. This paper proposes the reliability-based design optimization (RBDO) technique, which enables the optimum design that considers confidence level for the vibration characteristics of structural system. Response surface method (RSM) is utilized to approximate the performance functions describing the system characteristics in the RBDO procedure. The proposed optimization technique is applied to the pillar section design considering natural frequencies of a vehicle structure.

• International Journal of Automotive Technology
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• 제6권1호
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• pp.23-28
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• 2005

The presented investigation of shift clonk in a vehicle with front-wheel drive shows how a detailed analysis of the complete acoustic system with respect to excitation, transfer and radiation foremost enables possibilities of noise reduction to be worked out. One of the most important basics for the shift clonk analysis was a synchronous measurement of both, torsional vibrations in the drive train on the excitation side as well as airborne and structure-borne noise signals on the transfer and radiation side. Thus, root causes could be identified and improvement measures of the internal shift system could be worked out. An analysis of the transfer paths by means of airborne and structure borne noise measurements made evident that the side shafts were responsible for the disturbing frequencies in the transfer paths. With the help of the FE-simulation it was possible to develop measures of structure optimisation for the side shaft system. The realisation of these measures clearly reduced the shift-noises in the vehicle interior.

• 한국생산제조학회지
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• 제8권5호
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• pp.83-89
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• 1999

A seat frame structure in automotive vehicles made of polymer matrix composite to achieve weight reduction at low cost was developed. In order to design and manufacture the actual product studies on material selection and structural analysis were performed. Structural analysis was performed with a finite element method. The analysis was done for several cases suggested in various safety regulations. Each results was utilized to modify the actual shape to obtain a lighter, safer and more stable design. The final design was used to produce a sample bottom plate of the seat structure with reinforced by X-shape frame. Substitution of the material resulted in a weight reduction effect with equivalent strength fatigue and impact characteristics.

• 한국자동차공학회논문집
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• 제15권5호
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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.