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크리깅기법을 이용한 전륜 디스크 브레이크 모델의 스퀼 저감 해석
심현진(Hyoun-Jin Sim),조용구(Yong-Goo Joe),NOOR FAWAZI,오재응(Jae-Eung Oh) 대한기계학회 2007 대한기계학회 춘추학술대회 Vol.2007 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(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.
실험계획법을 이용한 차량 공조시스템의 시끄러움과 날카로움 분석
심현진(Hyoun-Jin Sim),윤태건(Taekun Yun),박상길(Sang-Gil Park),이해진(Hae-Jin Lee),이정윤(Jung-Yoon Lee),오재응(Jae-Eung Oh) 대한기계학회 2005 대한기계학회 춘추학술대회 Vol.2005 No.11
Since human listening is very sensitive when the sound hit him, the subjective index of sound quality is required. Therefore, at each situation of sound evaluation its composed with the sound quality factor. But, when substituting the level of one frequency band we could not see the tendency of substitution at whole frequency band during the sound quality evaluation. In this study a design of experiment is used. The frequency domain is divided into an equally 12 parts and each level of domain whether is given increase or decrease due to the change of frequency band based on ‘loud’ and ‘sharp’ of the sound quality is analyzed. By using the design of experiment the number of test is reduce very effectively by the number of experiment and each band the main effect will be as a solution. The case of sound quality for ‘loud’ and ‘sharp’ at each band, the change of band (increase or decrease of sound pressure or keep maintain) which will be the most effects on the characteristics of sound quality can be identify and this will be able to us to select the objective frequency band. Through these obtained results the physical changes of level at arbitrary frequency domain sensitivity can be adapted.
The Optimal Design of Low Noise of the Engine Cooling Fan using Kriging Method
Hyoun-Jin Sim(심현진),Sung-Hyoun Kim(김성현),Je-Seon Ryu(류제선),Kyung-Joon Cha(차경준),Jung-Yoon Lee(이정윤),Jae-Eung Oh(오재응) 대한기계학회 2005 대한기계학회 춘추학술대회 Vol.2005 No.11
This paper proposes an optimal design scheme to reduce the noise of the engine cooling fan by adapting Kriging with two meta-heuristic techniques. An engineering model has been developed for the prediction of the noise spectrum of the engine cooling fan. The noise of the fan is expressed as the discrete frequency noise peaks at the BPF and its harmonics and line spectrum at the broad band by noise generation mechanisms. The object of this paper is to find the Optimal Design for Noise Reduction of the Engine Cooling Fan. We firstly show a comparison of the measured and calculated noise spectra of the fan for the validation of the noise prediction program. Orthogonal array is applied as design of experiments because it is suitable for Kriging. With these simulated data, we can estimate a correlation parameter of Kriging by solving the nonlinear problem with genetic algorithm and find an optimal level for the noise reduction of the cooling fan by optimizing Kriging estimates with simulated annealing. We notice that this optimal design scheme gives noticeable results. Therefore, an optimal design for the cooling fan is proposed by reducing the noise of its system.
전산실험모형을 이용한 자동차 엔진 냉각홴의 저소음 설계
심현진(Sim, Hyoun-Jin),박상길(Park, Sang-Gul),조용구(Joe, Yong-Goo),오재응(Oh, Jae-Eung) 한국소음진동공학회 2009 한국소음진동공학회 논문집 Vol.19 No.5
This paper proposes an optimal design scheme to reduce the noise of the engine cooling fan by adapting Kriging with two meta-heuristic techniques. An engineering model has been developed for the prediction of the noise spectrum of the engine cooling fan. The noise of the fan is expressed as the discrete frequency noise peaks at the BPF and its harmonics and line spectrum at the broad band by noise generation mechanisms. The object of this paper is to find the optimal design for noise reduction of the engine cooling fan. We firstly show a comparison of the measured and calculated noise spectra of the fan for the validation of the noise prediction program. Orthogonal array is applied as design of experiments because it is suitable for Kriging. With these simulated data, we can estimate a correlation parameter of Kriging by solving the nonlinear problem with genetic algorithm and find an optimal level for the noise reduction of the cooling fan by optimizing Kriging estimates with simulated annealing. We notice that this optimal design scheme gives noticeable results. Therefore, an optimal design for the cooling fan is proposed by reducing the noise of its system.
황동건(Dong-Kun Hwang),심현진(Hyoun-Jin Sim),이정윤(Jung-Youn Lee),오재응(Jae-Eung Oh),유동호(Dong-Ho Yoo) 대한기계학회 2005 대한기계학회 춘추학술대회 Vol.2005 No.5
The reduction of the Vehicle interior noise has been the main interest of 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 HVAC sound among the vehicle interior noise has been reflected sensitively in the side of psychology. In previous study, we have developed to verify identification of source for the vehicle HVAC system through multiple-dimensional spectral analysis. Also we carried out objective assessments on the vehicle HVAC noises and subjective assessments have been already performed with 30 subjects. In this study, the linear regression models were obtained for the subjective evaluation and the sound quality metrics. The regression procedure also allows you to produce diagnostic statistics to evaluate the regression estimates including appropriation and accuracy. Appropriation of regression model is necessary to R² value and F-value. And testing for regression model is necessary to Independence, Homoscedesticity and Normality. To enhance sound quality, we applied active noise control (ANC) which is effective in the lowfrequency bandwidth. Primary noise of the HVAC system is less than 500㎐. As a result of ANC application, sound quality is improved by more quiet, powerful, expensive, smooth.