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Analysis of Vibro-acoustic Coupling Sound Field and Structure Vibration and Noise Isolation

FEI Chao-yang;CHEN Chang-zheng;ZHOU Bo;WANG Zhong

2012, 32 (2): 54-58. DOI: 103969/j.issn.1006-1355-2012.02.013

Abstract （1736）

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Taking measured loads spectrum generated by blower unit pipeline as excitation source, the room sound field and its vibro-acoustic coupling condition at different frequency are simulated using ANSYS and Virtual Lab sound field simulating software. Simulation results show that vibro-acoustic coupling could be negligible below 400Hz, but the strong vibro-acoustic coupling is existed above 400Hz. The simulation results are consistent with actual measuring results. Through analyzing frequency bandwidth characteristics of loads spectrum and noise spectrum, the double-layer vibration isolation system with general damping vibration isolator and small middle mass is established and its vibration transmission coefficient is calculated. Vibration insulation and noise reduction effects are satisfactory.

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Design and Achievement of Double-stage Vibration Isolation System of Scroll Compressor

WANG Yue;CHEN Chang-zheng;ZHAO Xin-guang;LIU Xin-hong

2011, 31 (6): 196-198. DOI: 10.3969/j.issn.1006-1355-2011.06.045

Abstract （1555）

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Vibration and noise of scroll compressors of air conditioning units at the top floor of an office building in an Economic and Technological Development Zone are excessively high. The noise and vibration of the units have severe impact on the downstairs offices. Through the testing of these units, it is found that the central air conditioning unit and its pipes have no vibration isolators at all, which form an acoustic bridge between the equipment and the building and cause the spread of solid sound. Therefore, vibration isolation must be considered according to the characteristic of the solid sound spread to effectively reduce the pollution of low frequency noise. Due to the actual situation of the top floor, a double-stage vibration isolation system is considered. With the calculation, the vibration isolation system is designed, and then it is made and installed to the equipment. Finally, a good isolation effect is obtained. The average value of the noise level is reduced by 20 dB.

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Study on a Special Noise Isolation Structure Based on Standing Wave Theory

GAN Xiao-ye;ZHAO Xin-guang;LIU Xin-hong;CHEN Chang-zheng

2011, 31 (4): 182-184. DOI: 10.3969/j.issn.1006-1355-2011.04.043

Abstract （1743）

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A new sound isolation structure is designed on the base of stationary wave theory for sound isolation processing of the relatively small noise sources with their waves propagating in narrow paths as in the ducts. This design is confirmed by an in-situ experiment. Results show that this structure is effective in sound absorption, and can eliminate the adverse impact of the stationary wave on machine itself.

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《Analyses of Dynamic Responses of Subway Tunnels with Different Sections under Vibration Loading》

LIU Jin;CHEN Chang-zheng;ZHAO Hui

2009, 29 (5): 38-42. DOI: 10.3969/j.issn.1006-1355.2009.05.01

Abstract （2426）

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Strength and deformation of soil around the subway tunnel is greatly affected by the vibration induced by the subway trains. In this paper, taking Beijing subway line 5 as an example, the dynamic responses of subway tunnels with rectangular and circular sections under train’s vibration loading are computed by means of the finite element code. The deformation of soil around the subway tunnels and the displacements of the ground surface are also given. The computation results for the two sections are analyzed and compared mutually. These results may provide some reference data for subway tunnel design。

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