• 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.

• 한국자동차공학회논문집
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• 제25권3호
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• pp.389-396
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• 2017

Restorations of automotive parts have been done ever since the first vehicle was produced. Because the most expensive parts of a vehicle are in the engine system, there have been various restoration methods developed for engine parts. In the case of commercial diesel engines, the fuel injection device is a key and expensive component. It also has a significant effect on vehicle performance. In particular, reduced engine power and increased exhaust gas emissions may result from mechanical damage due to abrasion of the spill valve in the fuel injection system of a diesel engine. In this paper, restoration techniques for damaged parts are applied to restore the abrasion of a spill valve of fuel injection, also called as the "unit injector", of commercial diesel engines. In order to recover the damage, optimized polishing techniques using hard-metal and coating processes are applied. To evaluate restoration techniques for the spill valve, performance and durability tests are performed on a test bench.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2014년도 추계학술대회 논문집
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• pp.581-586
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• 2014

In general vibration test considers both harmonic vibration and random vibration, When developing the vehicle component. But the effect of harmonic vibration is larger in the parts around the vehicle engine, sole testing the harmonic vibration is considered. In this study, the fatigue damage of the linear system fixed around the engine is analyzed when the effect of random vibration is higher, harsher than the normal road surface condition. In condition the vehicle speed and the engine RPM are similar, the higher the harshness of the road surface condition is, the larger the fatigue damage level is. Therefore both random vibration and harmonic vibration must be considered in vibration test of components around the engine. Proposing the sine on random(SOR) vibration test that can exam considering both of vibrations, harmonic and random.

• 한국자동차공학회논문집
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• 제15권4호
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• pp.27-32
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• 2007

Head-Up Display system makes it possible for the driver to be informed of important vehicle data such as vehicle speed, engine RPM or navigation data without taking the driver's eyes off the road. Long focal length optics, LCD with bright illumination, image generator and vehicle interface controllers are key parts of head-up display system. All these parts have been designed, developed and applied to the test vehicle. Virtual images are located about 2m ahead of the driver's eye by projecting it onto the windshield just below the driver's line of sight. Developed head-up display system shows satisfactory results for future commercialization.

• 대한토목학회논문집
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• 제38권6호
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• pp.1001-1012
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• 2018

국내 철도차량부품 제조 중소기업은 250여 개의 관련업체가 있으며 자체 기술력을 보유하기 보다는 외국 기술과 제품을 수입하여 철도차량의 부품을 제작 납품하는 형태로 생존하고 있다. 이로 인해 철도 핵심부품 산업은 해외 의존성이 높은 상황이다. 이에 정부에서는 철도차량부품 제조 중소기업 지원을 위해서 다양한 정책적 지원을 강화하고 있지만, 정부의 지원 정책이 철도차량부품 제조 중소기업이 안고 있는 문제점과 애로사항을 충분히 해결하지 못하고 있다. 철도차량부품 제조 중소기업이 국가경제의 경쟁력 강화에 기여할 수 있고 이들을 효과적으로 지원하기 위해서는 기술사업화 과정에서 중요한 촉진요인이 무엇인지 명확히 파악할 필요가 있다. 이에 본 연구는 철도차량부품 제조 중소기업의 기술사업화를 촉진하는 10개의 요인을 추출하였으며, 이들 지표의 중요도를 AHP (Analytic Hierarchy Process)를 이용하여 분석하였다. AHP 분석결과, 기업내부 요인이 가장 중요한 요인으로 나타났으며, 그 하위 항목으로는 '사업화 능력'이 가장 중요한 항목으로 분석되었다. 본 연구의 내용과 결과는 공공 연구기관 및 철도차량부품 제조 중소기업 지원 기관인 철도 운영기관의 기술사업화 지원 프로그램 기획과 지원 정책을 수립할 때 유용하게 이용될 수 있을 것으로 기대된다.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2002년도 춘계학술발표대회 논문집
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• pp.163-166
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• 2002

For the development of an all composite unmanned aerial vehicle (UAV), manufacturing consideration in design phase, works for composite parts fabrication, subassembly and final assembly are summarized. In design phase, to maximize the advantage of composite material, manufacturing processes such as cocuring, cobonding and secondary bonding are introduced. For the curing of designed parts, composite tools are designed and manufactured. Assembly jigs are designed to satisfy dimensional tolerance of the structure. Inspection criteria are established and applied to the manufacturing. Technical data about inspection items and methods are summarized as manufacturing specifications for the mass production of the UAV structure.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 추계 학술대회논문집(수송기계편)
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• pp.140-143
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• 2005

The hybrid CAE/CAT methods are widely applied to product development in various fields because this method can predict the response of the whole system when a part of the system is changed. Especially, the hybrid CAE/CAT method is very useful to predict tile vehicle NVH characteristics after changing some parts of the vehicle. Target parts can be established on the basis of test models and FE models of the prototype constructed in the planning stage of car development. In this study, the topic was focused on the proper test-based FBS application process to predict vehicle NVH characteristic. First, the test-based FBS method was apply to vehicle substructure and car-body. And then the test-based model was replaced with FE model to apply hybrid CAE/CAT method. The replaced FE model was modified through the optimization process. The interior noise in vehicle during the drive was predicted with Modified FE model, then the predicted results were verified by experimenting with actual modified model.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2008년도 춘계학술대회논문집
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• pp.980-985
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• 2008

This paper presents vehicle road test of a semi-active suspension system equipped with continuously controllable magnetorheological (MR) dampers. As a first step, front and rear MR dampers are designed and manufactured based on the optimized damping force levels and mechanical dimensions required for a commercial middle-sized passenger vehicle. After experimentally evaluating dynamic characteristics of the MR dampers, the test vehicle is prepared for road test by integrating current suppliers, real-time data acquisition system and numerous sensors such as accelerometer and gyroscope. Subsequently, the manufactured four MR dampers (two for front parts and two for rear parts) are incorporated with the test vehicle and a skyhook control algorithm is formulated and realized in the data acquisition system. In order to emphasize practical aspect of the proposed MR suspension system, road tests are undertaken on proving grounds: bump and paved roads. The control responses are evaluated in both time and frequency domains by activating the MR dampers.

• 한국소음진동공학회논문집
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• 제19권3호
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• pp.235-242
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• 2009

This paper presents vehicle road test of a semi-active suspension system equipped with continuously controllable magnetorheological(MR) dampers. As a first step, front and rear MR dampers are designed and manufactured based on the optimized damping force levels and mechanical dimensions required for a commercial middle-sized passenger vehicle. After experimentally evaluating dynamic characteristics of the MR dampers, the test vehicle is prepared for road test by integrating current suppliers, real-time data acquisition system and numerous sensors such as accelerometer and gyroscope. Subsequently, the manufactured four MR dampers(two for front parts and two for rear parts) are incorporated with the test vehicle and a skyhook control algorithm is formulated and realized in the data acquisition system. In order to emphasize practical aspect of the proposed MR suspension system, road tests are undertaken on proving grounds: bump and paved roads. The control responses are evaluated in both time and frequency domains by activating the MR dampers.

• 한국소음진동공학회논문집
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• 제17권10호
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• pp.958-966
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• 2007

This study presents full vehicle dynamics model for the dynamic characteristic analysis of chassis parts which are suspension and brake system. This vehicle dynamics model is appled to kinematics and quasi-static analysis for each chassis part. In order to develop the vehicle dynamics model, the parameters of each chassis element part which are bush, spring and damper are measured by experiment. Also the wheel forces and moments of 6 DOF are measured at each wheel center. These data are applied to input parameter for vehicle dynamics model. And the verification of the developed model is achieved to comparison with the experimental force data of spring, trailing arm and assist arm by using the load response by strain gauge. These experimental force data are acquired by road test at event surfaces of P/G which are belgian and chuck holes roads.