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크리깅기법을 이용한 전륜 디스크 브레이크 모델의 스퀼 저감 해석
심현진(Sim, Hyun-Jin),박상길(Park, Sang-Gil),김흥섭(Kim, Heung-Seob),오재응(Oh, Jae-Eung) 한국소음진동공학회 2008 한국소음진동공학회 논문집 Vol.18 No.10
Disc brake noise is an important customer satisfaction and warranty issue for many manufacturers as indicated by technical literature regarding the subject coming from Motor Company. This research describes results of a study to assess disk brake squeal propensity using finite element methods and optimal technique (Kriging). In this study, finite element analysis has been performed to determine likely modes of brake squeal. This paper deals with friction-induced vibration of disc brake system under contact friction coefficient. A linear, finite element model to represent the floating caliper disc brake system is proposed. The complex eigen-values are used to investigate the dynamic stability and in order to verify simulations which are based on the FEM model. In this paper, Kriging from among the meta-modeling techniques is proposed for an optimal design scheme to reduce the brake squeal noise.
심현진 ( Hyun-jin Sim ),김기태 ( Ki-tae Kim ),조선문 ( Sun-moon Jo ),고훈준 ( Hoon-joon Kouh ),유원희 ( Weon-hee Yoo ) 한국정보처리학회 2004 한국정보처리학회 학술대회논문집 Vol.11 No.1
인터넷에 있는 많은 응용프로그램들의 용도와 부가적인 정보를 아는 것은 매우 어렵다. 웹에는 수많은 정보들이 존재하고 이것들을 필요에 따라 정확하게 검색하는 것이 점점 어려워지고 있다. 이러한 어려움을 해결하기 위해 현재 메타데이터를 사용하여 웹 자원을 검색하는 연구가 활발하게 진행되고 있다. W3C는 메타데이터의 상호운용성과 통합을 위한 환경으로 RDF(Resource Description Framework)를 표준으로 정했다. 본 논문에서는 응용프로그램이나 프로그램 개발에 필요한 작은 단위의 프로그램에 대해 RDF를 이용하여 메타데이터로 만들고 이것을 대상으로 검색 가능하도록 하여 사용자가 원하는 정보를 보다 정확한 검색을 수행할 수 있도록 하였다.
심현진(Hyoun-Jin Sim),윤지현(Ji-Hyun Yoon),이정윤(Jung-Yoon Lee),오재응(Jae-Eung Oh) 대한기계학회 2007 대한기계학회 춘추학술대회 Vol.2007 No.10
In recent years, several studies of the practical application of noise and vibration control have been developed to plate. This paper proposes passive control scheme to reduce the structure borne noise of the plate using piezoelectric shunt damping techniques. The use of piezoelectric shunt damping in reducing vibration and sound radiation of structures has several advantages over passive visco-elastic materials. The model for a clamped plate bonded with piezoelectric shunt damping is built using Lagrangian and Hamilton’s principle. Using the Hamilton’s principle, the mechanical and electrical equations of the system can be obtained. The designs resulting from the simulation model are then implemented and evaluated by experiments. These experiments were carried out on the basis of quantitative and subjective performance measures. This technique suggests improving the efficiency of vibration and noise control at the high technology system.
ANALYSIS OF SOUND QUALITY FOR THE AUTOMOTIVE HVAC USING DESIGN OF EXPERIMENTS.
박상길(Sang-Gil Park),심현진(Hyun-Jin Sim),윤태건(Tae-Kun Yun),이유엽(You-Yub Lee),오재응(Jae-Eung Oh) 대한기계학회 2007 대한기계학회 춘추학술대회 Vol.2007 No.10
Since human hearing is very sensitive to sound, a subjective index of sound quality is required. Each situation of sound evaluation is composed of the Sound Quality (SQ) metrics. When substituting the level of one frequency band, we could not see the tendency of substitution at the whole frequency band during the SQ evaluation. In this study, a Design of Experiments (DOE) is used to analyze noise from an automotive Heating, Ventilating, and Air Conditioning (HVAC) system. The frequency domain is divided into twelve equal parts and each level of the domain is given an increase or decrease due to the change of frequency band based on the ‘loud’ and ‘sharp’ of the SQ analyzed. By using DOE, the number of tests is effectively reduced by the number of experiments, and the main result is a solution at each band. SQ in terms of ‘loud’ and ‘sharp’ at each band, the change of band (increase or decrease of sound pressure) or no change of band will have the most effect on the identifiable characteristics of SQ. This will enable us to select the objective frequency band. Through the results obtained, the physical level changes of the arbitrary frequency domain sensitivity can be adapted.
회귀모형과 신경망모형을 이용한 차량공조시스템의 음질 인덱스 구축 및 비교
박상길(Park, Sang-Gil),이해진(Lee, Hae-Jin),심현진(Sim, Hyun-Jin),이유엽(Lee, You-Yub),오재응(Oh, Jae-Eung) 한국소음진동공학회 2006 한국소음진동공학회 논문집 Vol.16 No.9
The reduction of the vehicle interior noise has been the main interest of noise and vibration harshness (NVH) engineers. The driver's perception on the vehicle noise is affected largely by psychoacoustic characteristic of the noise as well as the SPL. In particular, the heating, ventilation and air conditioning (HVAC) system sound among the vehicle interior noise has been reflected sensitively in psychoacoustics view point. Even though the HVAC noise is not louder than overall noise level, it clearly affects subjective perception to drivers in the way of making to be nervous or annoyed. Therefore, these days a vehicle engineer takes aim at developing sound quality as well as reduction of noise. In this paper, we acquired noises in the HVAC from many vehicles. Through the objective and subjective sound quality (SQ) evaluation with acquiring noises recorded by the vehicle HVAC system, the simple and multiple regression models were obtained for the subjective evaluation 'Pleasant' using the semantic differential method (SDM). The regression procedure also allows you to produce diagnostic statistics to evaluate the regression estimates including appropriation and accuracy. Furthermore, the neural network (NN) model were obtained using three inputs(loudness, sharpness and roughness) of the SQ metrics and one output(subjective 'Pleasant'). Because human's perception is very complex and hard to estimate their pattern, we used NN model. The estimated models were compared with correlations between output indexes of SQ and hearing test results for verification data 'Pleasant'. As a result of application of the SQ indexes, the NN model was shown with the largest correlation of SQ indexes and we found possibilities to predict the SQ metrics.
수치해석을 통한 충격 시 접시 스프링의 비선형 특성 고찰
방승우(Bang, Seung-Woo),이해진(Lee, Hae-Jin),심현진(Sim, Hyun-Jin),박상길(Park, Sang-Gil),이정윤(Lee, Jung-Youn),오재응(Oh, Jae-Eung) 한국소음진동공학회 2008 한국소음진동공학회 논문집 Vol.18 No.2
General coil spring has linearity. However, disc spring has non-linearity so that using this non-linearity disc spring can be designed to do shock-absorbing in cases we need because shock response also has non-linearity. By changing the shape and stacking number, it is satisfactory with response of displacement, velocity and acceleration. Conventionally, disc spring was used to control the vibration against huge load and limited space. However, it is limitedly used because of difficulty of the designing guidance. Therefore, disc spring is needed to study further in order to apply it widely. Response of disc spring is compared to response of coil spring by changing $h_o/t$ ratio with computer simulation and the usage of disc spring is increased through analysis of effect of design factors. The purpose of this paper is that the shock response of disc spring is calculated through numerical simulation and effect of $h_o/t$ and stiffness is analyzed to broad usage so that design factor of disc spring is presented.