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Study on the Effective Region of Excitation Force of Magnetic Rubber Layer Damping Treatment
LI Ming
   2012, 32 (3): 198-200.   DOI: 10.3969/j.issn.1006-1355.2012.03.045
Abstract （1547）            Save
The reason that the damping performance of magnetic rubber layer damping treatment (MRLD) depends on the force excitation has been analyzed. Analyzing the different dissipation energy mechanisms between MRLD and the passive constrained layer damping treatment (PCLD), the ratio of dissipation energy of MRLD to dissipation energy of PCLD was obtained. And the effective range of exciting force, in which MRLD achieves better damping than PCLD, was estimated. The results show that the material loss factor has a decisive influence not only on the effective range, but also on the best damping improvement of MRLD.
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Analysis of Noise Control of an Urban 110 kV Indoor Substation
LI Ming;CHEN Jin-dong
   2012, 32 (1): 105-108.   DOI: 10.3969/j.issn.1006-1355-2012.01.025
Abstract （3199）            Save
The characteristics of an urban 110kV indoor substation and its noise are described. Its noise control methods are briefly analyzed. An example of noise control of a typical urban 110 kV indoor substation—Shanghai Anshan 110 kV substation, is introduced. It can be used as a reference for similar projects.
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Overview of Domestic and European Sound Insulation Standards for Civil Building
LI Ming-bin;LU Feng-hua
   2012, 32 (1): 96-98.   DOI: 10.3969/j.issn.1006-1355-2012.01.023
Abstract （1696）            Save
Noise pollution has become one of the serious problems in our daily life. The standard for design of sound insulation for civil buildings is of important significance for people to have a comfortable acoustic environment. In this paper, a new domestic standard for sound insulation design of civil buildings is analyzed and compared with the standards of some European countries. This overview may provide some help for implementation of the new standard.
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Research of Hybrid Sound Absorption Based on Characteristic Impedance
ZHU Cong-yun;LI Ming-li;JIANG Chun-ying
   2011, 31 (4): 185-189.   DOI: 10.3969/j.issn.1006-1355-2011.04.044
Abstract （2485）            Save
Aiming at the character that the effect of the active sound absorption is very good for low frequency acoustic wave, and poor for middle and high frequency sound wave, a new hybrid absorption system is proposed in this paper. This system consists of a layer of absorbent material and a movable rigid wall. The speed of the movable rigid wall can be adjusted in order to make the acoustic impedance of the absorption material match the acoustic impedance of the air, so that the absorption coefficient of the hybrid system can reach the maximal. A numerical calculation and an experiment are carried out for the case of normal incident plane wave. Both results show that the absorption coefficient of the hybrid system can reach 0.8-1.0 in the frequency range of 100-2 000 Hz, but the absorption effect of the system has not been improved very much when the frequency of the sound wave is higher than 2 000 Hz.
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Dynamic Analysis of Rotor System Coupled by Rubber Bearings
LI Fang; SHUAI Chang-geng;HE Lin;YANG Xue;LI MING
   2011, 31 (3): 37-41.   DOI: 10.3969/j.issn.1006-1355-2011.03.009
Abstract （2028）            Save
Mathematical model of a large rotor system supported on rubber bearings is proposed and its dynamics is discussed in this paper. Firstly under the assumption of small perturbation, the dynamic characteristics of rubber bearing is described by Kelvin-voigt model. Then based on the analytical mechanics the motion equations are deduced. For a typical ship propulsion system, a numerical analysis is carried out. The results show that the vibration of the lowest modal is mainly from the propeller, and even at the low rotating speed the amplitude on the propeller rubber bearing under propeller unbalance is larger than the thickness of water film of the rubber bearing in general, consequently phenomena of the stick-slip, spirant and wear between rubber staves and rotor may be produced.
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