HY-2 Satellite Delivered with Sound Performance

The HY-2 marine satellite was delivered to the State Oceanic Administration by CASC,the manufacturer of the satellite,on March 2,2012 and has been put into operational service formally.The HY-2 satellite is the first China-made marine satellite capable of

Sound Insulation Performance of Structural Wood Wall Integrated with Wood Plastic Composite

The sound insulation performance is an important technical index for evaluating the physical property of the building wall.Three kinds of structural wood walls integrated with wood plastic composite(WPC)were designed.And the sound insulation performance of the walls was studied.The results showed that for the wall that constructed by the WPC as the wall studs,compared with the one that constructed by the pine wood as the wall studs,the deviation of their sound insulation was lower than±3 dB.The wall’s external panel material had significant effect on the wall’s sound insulation property,and the contribution of the wood-plastic panel to the sound insulation was much higher than that of the polyvinyl chloride(PVC)plastic hanging board.The surrounding sealing quality of the wall’s external panel material had an important influence on the sound insulation effect of the building wall,and the panel of the wood plastic interior wall had less influence on the sound insulation performance of the wall.Taking the sound-absorbing cotton or non-woven fabric as elastic strips was an effective technical measure to improve the sound insulation performance of the walls.The sound insulation was improved by 2.4 dB and 3.1dB respectively after the correction of pink noise spectrum,and increased by 2.8 dB and 3.6 dB respectively after the correction of traffic noise spectrum.

Sound transmission performance on cavity ferrocement panels with ties

Ferrocement panels have been used in low cost housing construction in developing countries. This study focuses on the sound transmission performance of cavity ferrocement panels with ties. In this study, panels have been cast and tested in transmission loss suite specially designed and constructed for testing their sound transmission performance experimentally. The measured results agree well with the theoretical model.

Topology Optimization of Acoustic-Mechanical Structures for Enhancing Sound Quality

Sound quality is one of the essential criteria for measuring the acoustic performance of acoustic devices.In contrast to the optimization of sound characteristics,both the quantitative description of sound quality and the numerical instability that may occur during optimization need to be investigated.In the present work,an explicit topology optimization approach is proposed to enhance the sound quality of acoustic-mechanical structures,where the sound quality is described,resorting to frequency response within a specified frequency band.To this end,the moving morphable component(MMC)-based approach is adopted to achieve the explicit topology design,and the mixed finite element method is introduced to evaluate the sound quality.With the use of the explicit description of MMC,the acoustic-structure boundary can be captured accurately,which is important for acoustic response analysis.Moreover,a regularization topology optimization formulation is also developed to avoid the numerical issues produced in some special frequency bands.Numerical examples demonstrate the effectiveness of the proposed approach in improving sound quality performance.