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승용차의 실내 부밍 소음 저감을 위한 시험 절차 및 개선에 관한 연구
정명식(MyungSik Jeong),국형석(Hyungseok Kook),고강호(Kangho Ko),허승진(Seung-Jin Heo),김찬묵(Chan Mook Kim) 한국자동차공학회 2003 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
Reduction of structure-borne noises in the vehicle compartments has been one of the primary concerns in the development of vehicles. The booming is an annoying low frequency interior noise and the vibration of the enclosing body panels due to the engine excitation is one of the major contributors.<br/> In this work, a series of tests were performed to identify the noise source and paths of the interior booming noise of<br/> a passenger vehicle. The tests include baseline test, structural modal analysis, acoustic modal analysis, acoustic sensitivity test, and panel contribution analysis. From the baseline test, the rear seat was found to be louder than the front seat at specific frequency ranges. Then, experimental results from other tests are collected and analyzed to find the causes for the apparent difference in the sound pressure levels between the front and the rear seats. Finally, by using the panel contribution analysis, the most contributive panel is identified, and the panel is modified to yield a reduced sound pressure level at the rear seat.
전차량 모델링 및 하중변화가 고려된 ABS에 대한 연구
이재훈(Jaehoon Lee),이창배(Changbae Lee),국형석(Hyungseok Kook),박기홍(Kihong Park),허승진(Seung-Jin Heo) 한국자동차공학회 2009 한국자동차공학회 부문종합 학술대회 Vol.2009 No.4
This paper uses a high degree automobile dynamic model to simulate better a real vehicle with an electronic control system based on Rapid-Control Prototyping (RCP). Using this model, this paper studies Anti-lock Brake System(ABS) to improve both braking and steering abilities. Current ABS uses consistent vertical force with a slip ratio, which is a difference between a vehicle's speed and a wheel's, from 0.1 to 0.3. However, because the maximum vertical force depends on a tire model's vertical force, the slip ratio was adjusted as vertical weight changes to improve ABS's performance.
판넬 기여도 해석을 이용한 승용차 실내 소음 분석 기법에 관한 연구
진용선(Yongsun Jin),김찬묵(Chanmook Kim),고강호(Kangho Ko),허승진(Seungjin Heo),국형석(Hyungseok kook),사종성(Jongsung Sa) 한국자동차공학회 2003 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
In this paper. the panel contribution analysis is used to identify the noise contribution of each sub-panel of car body to the total radiated noise. The accelerations of panels are measured in the normal direction on the outer surface of car body during operation. Acoustic transfer function, which has great influence on the panel contribution, is experimentally measured. In this procedure, volume acceleration of loudspeaker is defined by the application of equivalent area and a manifestation of the vibro-acoustical reciprocity. The panel contribution method is validated by comparing the radiated interior noise with the calculated radiated noises from each sub-panel. Contribution of panels for interior noise is ranked and problematic sub-panels of the car can be re-designed or reinforced according to the results.
구조 음향 상반 원리를 이용한 승용차 차체 소음 민감도 측정 및 실내 소음 개선
전준식(Junsik Jeon),허승진(Seungjin Heo),김찬묵(Chanmook Kim),국형석(Hyungseok Kook),고강호(Kangho Ko) 한국자동차공학회 2003 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
This paper presents a experimental method for reduction of interior noise in compartment of passenger car. Though results in Wide-Open Throttle valve(WOT), the studied vehicle has a Interior noise problem at rear passenger seats. In order to identify the Noise transfer path of interior noise, Noise transfer function(NTF) of panels is fulfilled. The NTF obtained by experiment using Vibro-acoustic reciprocity. Using this methods, it has been founded that rear part of the roof and rear window shield glass of the test car were a noise source for the Interior noise. Based on these results, we verified that it is identical with Panel contribution analysis(PCA).
국형석,고강호,정명식 국민대학교 생산기술연구소 2003 공학기술논문집 Vol.26 No.-
Reduction of structure-borne noises in the vehicle compartments has been one of the primary concerns in the procedure of development of vehicles. Booming is an annoying low frequency interior noise and the vibration of the enclosing body panels due to the engine excitation is one of the major contributors. In this work, a series of tests were performed to identify the noise source and paths of the interior booming noise of a passenger vehicle. The tests include baseline test, structural modal analysis, acoustic modal analysis, acoustic sensitivity test, and panel contribution analysis. From the baseline test, the rear seat was found to be louder than the front seat at specific frequency ranges. Then, experimental results from other tests are collected and analyzed to find the causes for the apparent difference in the sound pressure levels between the front and the rear seats. Finally, by using the panel contribution analysis, the most contributive panel is identified, and the panel is modified to yield a reduced sound pressure level at the rear seat.
Random Array Design Based on the Statistical Properties
Kook, Hyungseok 국민대학교 생산기술연구소 2002 공학기술논문집 Vol.25 No.-
This article is the second part of the research on statistical properties of random arrays. In this study, analytical methods based on statistical approaches to predict mean values and variations of the peak sidelobe levels of random arrays are proposed. First, the probabilistic distributions of the sidelobe levels at a few arbitrary points in the wavenumber domain are investigated. Then it is shown that the distributions follow the Weibull distribution with reasonable accuracy. And then, a simple and intuitive analytical method is proposed to estimate the statistical properties for the distribution of the peak sidelobe levels.