CZ HNU Institute of Machinery Equipment

Changzhou, China

CZ HNU Institute of Machinery Equipment

Changzhou, China
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Xie X.,Hunan University | Xie X.,CZ HNU Institute of Machinery Equipment | Cao Y.,Hunan University | Wang X.,Hunan University | And 2 more authors.
Qiche Gongcheng/Automotive Engineering | Year: 2017

In view of that the contribution of complex noise source to the noise of field points can not completely represent the contribution of that noise source to the whole interior noise of a large or medium bus, a methology for measuring contributions of multi-input to multi-output is put forward. Firstly through spectrum analysis, the signal features of interior noise of a bus are obtained, and the partial coherence functions of different noise sources to different field points under idling condition are calculated. Then the natural frequency of interior cavity is analyzed by acoustic modal test. Finally, “contribution coefficient sum” and “total contribution coefficient sum”, as two new evaluation parameters based on partial coherence function are introduced, by which and combined with acoustic modal features, the contributions of noise sources such as air induction, exhaust, engine and cooling fan to the overall interior noise of bus, as well as the influences of each other are evaluated, and the main noise sources and corresponding frequency bands needed to modify are determined, providing a gaidance for the effective attenuation of inteior noise of bus. © 2017, Society of Automotive Engineers of China. All right reserved.

Li K.,Hunan University | Liu J.,Hunan University | Han X.,Hunan University | Jiang C.,Hunan University | Qin H.,CZ HNU Institute of Machinery Equipment
Tribology International | Year: 2016

In this paper, a laboratory method based on equivalent dynamic load reconstruction is proposed for the identification of oil-film coefficients. When modeling the rotor, the oil-film supports are considered as its dynamic load boundary conditions. Consequently, the identification of oil-film coefficients is first converted to the reconstruction of equivalent dynamic loads. Through Green's function method and regularization, the equivalent dynamic oil-film loads can be steadily and precisely reconstructed. Then, according to the mechanical relationships between the oil-film properties and the corresponding equivalent loads, the oil-film stiffness and damping coefficients are identified using least square scheme. A rotor structure with two journal bearings is investigated and the identification results of oil-film coefficients demonstrate the validity and accuracy of the proposed method. © 2016 Elsevier Ltd

Yin S.H.,Hunan University | Yin S.H.,CZ HNU Institute of Machinery Equipment | Wang Y.Q.,Hunan University | Wang Y.Q.,CZ HNU Institute of Machinery Equipment | And 5 more authors.
Advanced Materials Research | Year: 2013

In this paper, a novel area taking MRF process using permanent magnet as excitation was proposed. Four types of permanent magnet configurations were considered. Polishing experiment was conducted. Effects of different permanent magnet configurations on material removal rate (MRR) were discussed. © (2013) Trans Tech Publications, Switzerland.

Xu Z.,Hunan University | Yin S.,Hunan University | Yin S.,CZ HNU Institute of Machinery Equipment | Chen F.,Hunan University | And 2 more authors.
International Journal of Abrasive Technology | Year: 2015

The ultrasonically assisted polishing (UAP) has been successfully applied to precision polishing due to its good surface quality and high removal efficiency. In this paper, the mode of UAP with two-axis ultrasonic vibration was introduced, a novel asymmetrical structural model of two-axis ultrasonic vibration transducer driven by the single actuator was developed, the principle of new transducer was explained, and its detailed structure was determined by assistance of finite element method (FEM) analysis. Polishing experiments were carried out on tungsten carbide mould with the developed transducer, the relationship of the polishing parameters and the surface roughness were analysed. The experimental results show that the workpiece surface quality with presented method changed from the original Ra 20.1 nm to 5.0 nm. © 2015 Inderscience Enterprises Ltd.

You Y.,Hunan University | Chen F.,Hunan University | Chen F.,CZ HNU Institute of Machinery Equipment | Gong S.,Hunan University | And 2 more authors.
Zhongguo Jixie Gongcheng/China Mechanical Engineering | Year: 2014

A forming method of grinding wheel was introduced based on ring-magnetic field control to make abrasive particle arrange regularly. A forming device of micro diamond powder wheel was designed. Its magnetic circuit and ring-magnetic field distribution were simulated. After observing the magnetic field distribution, the grinding wheels were produced in the forming device and tungsten carbide test specimens were ground. The surface roughness value of test specimens is as 29 nm. Compared with grinding wheels non magnetic field control forming, the surface quality is improved obviously.

Xie X.-P.,Hunan University | Xie X.-P.,CZ HNU Institute of Machinery Equipment | Jiang B.,Hunan University | Jiang B.,CZ HNU Institute of Machinery Equipment | Lei F.,Hunan University
Zhendong yu Chongji/Journal of Vibration and Shock | Year: 2015

A method combining the model order reduction and its parameters optimization was proposed to achieve the rapid calculation for experimental modal analysis. The indirect model reduction method was used in least square complex frequency domain to achieve the order reduction of system characteristic matrix. An optimization model was established based on the parametric description of the characteristic matrix. The system's degrees of freedom were optimized and reduced using the differential integrated comprehensive optimization strategy. The genetic algorithm was used to obtain the global optimization and reduction of parameters. The application of the fast calculation method in the experimental modal analysis of a heavy truck cab's body-in-white proves the effectiveness of the method and the improvement in computational efficiency. The method establishes a solid foundation for online detection and diagnosis of structural dynamics characteristics under continuous excitation condition. © 2015, Chinese Vibration Engineering Society. All right reserved.

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