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Chen S.M.,Jilin University | Wang D.F.,Jilin University | Zan J.M.,Changan Automobile Engineering Institute
Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering | Year: 2012

In order to understand the brake judder of a passenger car, the brake judder test of a passenger car was performed with initial speeds of 90, 120, and 150 km/h, end speed of 20 km/h, and pedal forces of 25, 30, 35, and 40 N on a roller dynamometer in a semi-anechoic chamber. The pressure fluctuation of the brake fluid pipe was presented. The accelerations of the steering wheel were recorded at vertical, lateral, and radial directions respectively, and the frequency analysis of the brake judder was also performed. The frequency response functions of the steering system were measured in order to understand the cause of the brake judder. Meanwhile, the multibody system dynamics model of the test vehicle was created with a flexible body and steering system. The brake torque calculated with the brake fluid pressure of the brake pipe in the brake judder test was exerted on the brake systems. The simulated accelerations of the steering wheel were calculated at three different directions, and the frequency analysis of the brake judder was also presented. The design of experiment was presented in order to reduce the brake judder and improve the comfort of the vehicle. An orthogonal array table was designed with 13 factors and 3 levels. The optimum combination was confirmed. The brake judder was also simulated, and the accelerations of the steering wheel were also calculated. Furthermore, the optimization results were verified by the brake judder test. The verification of the optimization indicates that the optimization results are correct and effective. © IMechE 2012. Source


Zheng W.,Huazhong University of Science and Technology | Zheng W.,State Key Laboratory of Vehicle NVH and Safety Technology | Lei Y.,State Key Laboratory of Vehicle NVH and Safety Technology | Lei Y.,Changan Automobile Engineering Institute | And 3 more authors.
Shock and Vibration | Year: 2013

The potential of using topology optimization as a tool to optimize the passive constrained layer damping (PCLD) layouts with partial coverage on flat plates is investigated. The objective function is defined as a combination of several modal loss factors solved by finite element-modal strain energy (FE-MSE) method. An interface finite element is introduced to modeling the viscoelastic core of PCLD patch to save the computational space and time in the optimization procedure. Solid isotropic material with penalization (SIMP) method is used as the material interpolation scheme and the parameters are well selected to avoid local pseudo modes. Then, the method of moving asymptote (MMA) is employed as an optimizer to search the optimal topologies of PCLD patch on plates. Applications of two flat plates with different shapes have been applied to demonstrate the validation of the proposed approach. The results show that the objective function is in a steady convergence process and the damping effect of the plates can be enhanced by the optimized PCLD layouts. © 2013 - IOS Press and the authors. All rights reserved. Source


Chen S.-M.,Jilin University | Wang D.-F.,Jilin University | Song X.-W.,Jilin University | Chen J.,Jilin University | Zan J.-M.,Changan Automobile Engineering Institute
Zhendong yu Chongji/Journal of Vibration and Shock | Year: 2010

The basic reciprocity relation for two sub-systems was demonstrated, and the hybrid FE-SEA equation was given too. Through numerical simulations, the hybrid FE-SEA model of a cavity-plate-cavity system was built, and the SEA model of the system was built at the same time. The modal density of the sound cavity and the coupling loss factor between the sound cavity and the plate were calculated, and the radiation efficiencies of the FE plate and the SE plate were also computed. The response of the cavity-plate-cavity system was calculated, and the response result of the FE-SEA model was compared with that of the SEA model. The causes of the error in the SEA model and the hybrid FE-SEA model were analyzed. The contrast results indicated that the two models have a good consistency in mid-high frequency band. The hybrid FE-SEA model and the SEA model of the cavity-rear windshield-cavity were also built. The excitation of the inside cavity was measured, and the response sound pressure levels(SPL) of the hybrid FE-SEA model and the SEA model were calculated. The SPLs were compared with experimental results, the contrast results indicated that the SPLs of the two models have a good consistency in mid-high frequency band, and the SPL of the hybrid FE-SEA model has a good consistency with the experimental one. Source


Chen S.-M.,Jilin University | Wang D.-F.,Jilin University | Cao X.-L.,Jilin University | Zan J.-M.,Changan Automobile Engineering Institute
Zhendong Gongcheng Xuebao/Journal of Vibration Engineering | Year: 2010

The basic reciprocity relation for a random component was demonstrated, the reciprocity relation for a random component was introduced through the wave approach and the modal approach. The coupling between two area junction subsystems was also introduced. The hybrid FE-SEA equation was given at the last demonstration for the theoretic results. Hybrid FE-SEA model of the car was built, the radiation efficiencies of the body panels of the car were calculated, and the excitations of the powertrain mounts and body suspensions of the car were measured. The acoustic excitation of the engine cabin was measured in anechoic room. And CFD wind tunnel was built to compute the wind excitations. Meanwhile, the car interior noise was predicted by the hybrid FE-SEA model subjected to all of excitations. Furthermore, the prediction result of the car interior noise was verified by the experimentation, and the reasons of the error were analyzed. The analysis result shows that the absolute error is less than 2.5 dB (A), the prediction precision is satisfied with engineering requirement, and the method of FE-SEA modeling is effective to predict middle frequency noise within the car interior. Source


Chen S.,Jilin University | Wang D.,Jilin University | Liu B.,Changan Automobile Engineering Institute
Fluctuation and Noise Letters | Year: 2013

This paper investigates optimization design of the thickness of the sound package performed on a passenger automobile. The major characteristics indexes for performance selected to evaluate the processes are the SPL of the exterior noise and the weight of the sound package, and the corresponding parameters of the sound package are the thickness of the glass wool with aluminum foil for the first layer, the thickness of the glass fiber for the second layer, and the thickness of the PE foam for the third layer. In this paper, the process is fundamentally with multiple performances, thus, the grey relational analysis that utilizes grey relational grade as performance index is especially employed to determine the optimal combination of the thickness of the different layers for the designed sound package. Additionally, in order to evaluate the weighting values corresponding to various performance characteristics, the principal component analysis is used to show their relative importance properly and objectively. The results of the confirmation experiments uncover that grey relational analysis coupled with principal analysis methods can successfully be applied to find the optimal combination of the thickness for each layer of the sound package material. Therefore, the presented method can be an effective tool to improve the vehicle exterior noise and lower the weight of the sound package. In addition, it will also be helpful for other applications in the automotive industry, such as the First Automobile Works in China, Changan Automobile in China, etc. © 2013 World Scientific Publishing Company. Source

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