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차량용 브레이크 코너 모듈에서 마찰재의 온도와 압력에 따른 물성치 변화를 고려한 스퀼 소음 해석 연구
조호준(Hojoon Cho),김정태(Jeong-Tae Kim),채호중(Ho-Joong Chae) 한국소음진동공학회 2012 한국소음진동공학회 학술대회논문집 Vol.2012 No.10
This paper is a study on squeal noise simulation under the consideration of temperature and pressure dependent material properties of friction material. For this, data of pressure and temperature dependent material properties of lining is achieved by using lining data base and exponential curve fit. Complex eigenvalue analysis is performed for predicting squeal noise frequency and instability and chassis dynamo test is performed for achieving squeal noise frequency, sound pressure level, occurrence temperature & pressure. Initial multi models are composed for considering complex interface conditions such as pad ear-clip, piston-housing and guide pin-torque member. The simulation result of base models is compared with the test result. Squeal noise simulation under the consideration of temperature and pressure dependent material properties of friction material is performed and analyzed using multi models. And additional condition is disc material property variation. Entire simulation conditions are combined and analyzed. Finally, this paper proposes direction of the warm squeal noise model.
차량용 브레이크 코너 모듈에서 패드 접촉 면압 분포가 스퀼 현상에 미치는 영향
조호준(Hojoon Cho),이재한(Jaehan Lee),이종화(Jongwha Lee),장진희(Jinhee Jang),김인동(Indong Kim) 한국자동차공학회 2009 한국자동차공학회 학술대회 및 전시회 Vol.2009 No.11
Automotive disk brakes generally perform braking by means of friction between the brake disk and pads. Due to the friction, various brake noise can generate from low frequency vibration and high frequency noise. Especially, squeal noise, which generates high frequency noise of pure tone, leads to unpleasant feeling not only to driver but also pass-by people and makes warranty issue of high level. This paper is a study of pad contact pressure distribution on squeal noise phenomenon based on finite element analysis and experiment. For this, modal testing of components and assembly model in a brake corner module is performed and correlated with finite element model. Mode map of components and assembly is composed by performing modal simulation of a correlated finite element model. Operating deflection shape is obtained at squeal noise occurrence condition by using 3D laser vibrometer. Instability mode of complex eigenvalue analysis result is correlated with ODS through changing boundary conditions of FE model. Static pad pressure distributions are measured before and after squeal noise dynamo test, and are simulated in accordance with pad arc lengths of radial chamfer. The Effective pad pressure distribution is determined through analysis of pressure distribution results. Instability mode and mode map is analyzed for finding main factors of squeal noise occurrence. Finally, this paper proposes the design recommendation and complex eigenvalue analysis model using effective pressure distribution.
디스크 브레이크에서 열섬 천이가 저더 현상 발생에 미치는 영향
조호준(Hojoon Cho),조종두(Chongdu Cho),맹주원(Joowon Maeng),이용산(Yongsan Lee),조기철(Kicheul Cho) 한국자동차공학회 2006 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
Hot judder phenomenon makes serious problems such as to be uneasiness to drivers or to decrease braking force of vehicle. Because judder vibration makes high magnitude vibration occurrence and thermal problem of brake disk in accordance with hot spots growth at the same time. Therefore it is necessary to reduce or eliminate judder phenomenon by understanding and analyzing origins of hot spot phenomenon. In this experimental study, mode shapes and frequencies related to hot spots were measured by modal testing. For increasing results of modal testing, mode analysis was calculated by finite element analysis. For coupled analysis of disk thickness variation (DTV) and judder vibration, temperature distribution of brake disk, DTV and vibration were measured by interval of 30 seconds in accordance with pressure of master cylinder at the same time. These were conducted by chassis-dynamometer. Hot spot measurements were photographed by using infrared camera. As results, coupled analysis of DTV and judder vibration was performed and relationship between temperature distribution and mode shapes was analyzed.
차량용 브레이크 시스템의 Low Frequency Noise 해석 연구
조호준(Hojoon Cho),이재한(Jaehan Lee),이종화(Jongwha Lee),정명구(Myoungkoo Chung),오정용(Jungyong Oh),장진희(Jinhee Jang),김인동(Indong Kim) 한국자동차공학회 2010 한국자동차공학회 부문종합 학술대회 Vol.2010 No.5
Brake low frequency noise phenomena (Moan, Groan Noise) are occurred by frictional stick-slip between pads and a rotor. When frictional stick-slip between pads and a rotor is occurred, this excitation source makes resonance of suspension system, which can generate structure-borne noise. Therefore, mechanism of low frequency noise phenomena should be systematically approached and analyzed in many different directions. In this study, automotive brake low frequency noise phenomena were approached and analyzed through three different simulation methods. A complex Eigenvalue analysis, steady state dynamic analysis and dynamic explicit analysis were performed and compared in an automotive drum brake system of trailing arm suspension type. For this, modal testing in the state of vehicle was performed and correlated with finite element analysis. Drum brake system was used in brake squeal noise simulation FE model which were correlated with brake components and sub-assembly modal testing results. Finally, causes of low frequency noise phenomena in this brake system were analyzed through three simulation methods.
조호준(Hojoon Cho),조종두(Chongdu Cho),김명구(Myoung-Gu Kim),맹주원(Juwon Maeng),이용산(Yongsan Lee) 한국자동차공학회 2006 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
Hot spot phenomenon that occurs, during judder vibration, is locally concentrated heat due to friction between brake disk and pad. It is important to understand the reason behind hot spot phenomenon, for reduction of judder vibration. In this experimental study, experiments were performed in accordance with rotation speed of brake disk, pressure of master cylinder and pad length for achieving different aspects of hot spot phenomenon. Temperature distribution of hot spot was obtained by using the infrared camera. As the hot spot occurred, vibration was measured and frequency analysis was performed. Finite element analysis of thermal deformation of disk was performed by using temperature distribution that was achieved by experimental results. It was observed that the excitation frequency band of frictional contact and frictional force mainly affects the hot spot phenomenon.
Brake Squeal Noise를 유발하는 Brake Contact Interface와 Rotor의 In-Plane Modes에 관한 연구Ⅱ
김경수(Kyungsoo Kim),조호준(Hojoon Cho),김두영(Dooyoung Kim),최원석(Wonseok Choe),박영준(Youngjoon Park),백봉범(Bongbum Back),김한규(Hankyu Kim),고승석(Seungseok Ko),정명구(Myoungkoo Chung) 한국자동차공학회 2010 한국자동차공학회 학술대회 및 전시회 Vol.2010 No.11
For many years, brake noise has been one of the top automotive brake warranty issues, and many studies have been conducted to reduce the squeal phenomenon by improving the rotor-pad contact interface or by decoupling modes inducing squeals. This is additional research of ‘A study of Brake Contact Interface and Rotor In-Plane Modes Induced Disc Brake Squeal noise’. This paper considers the different brake contact interfaces affecting high frequency brake squeal and introduce an effective way of reducing the problem by improving one of the brake secondary contacts. Furthermore, the reason of improving of brake secondary contact has a positive effect is investigated by modal analysis & squeal noise analysis.
Brake Squeal Noise를 유발하는 Brake Contact Interface와 Rotor의 In-Plane Modes에 관한 연구
이종화(Jongwha Lee),조호준(Hojoon Cho),이재한(Jaehan Lee),최원석(Wonseok Choe),김세혁(Sehyuk Kim),정명구(Myoungkoo Chung),오정용(Jungyong Oh),김인동(Indong Kim) 한국자동차공학회 2010 한국자동차공학회 부문종합 학술대회 Vol.2010 No.5
For many years, brake noise has been one of the top automotive brake warranty issues, and many studies have been conducted to reduce the squeal phenomenon by improving the rotor-pad contact interface or by decoupling modes inducing squeals. This research investigates brake contact interface and rotor in-plane modes which generate brake squeal noise and conduct a robust correlation between CAE and Test by using methods such as the 3D laser vibrometry ODS and modal mapping. This paper considers the different brake contact interfaces affecting low frequency brake squeal and introduce an effective way of reducing the problem by improving one of the brake secondary contacts. On the discussion with the rotor in-plane mode, importance of rotor radial mode on inducing squeal issues and noise risks being introduced by rigid in-plane modes on assembly restraint conditions are topics that are often being left aside on former researches.