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The structural-acoustic coupling model for isotropic thin elastic plate was extended to honeycomb sandwich plate (HSP) by applying Green function method. Then an equivalent circuit model of the weakly-strongly coupled system was proposed. Based on that, the estimation formulae of the coupled eigenfrequency were derived. The accuracy of the theoretical predictions was checked against experimental data, with good agreement achieved. Finally, the effects of HSP design parameters on the system coupling degree, the acoustic cavity eigenfrequency, and sound pressure response were analyzed. The results show that mechanical and acoustical characteristics of HSP can be improved by increasing the thickness of face sheet and reducing the mass density of material. 相似文献
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直流UPS供电的优点很多,首先是节能,直流UPS将普通UPS的双变换(交一直一交)简化为交一直一次变换,理论上可降低一半的能耗;再有就是高可靠性,直流UPS的供电可以直接用电池,减少了逆变器这个中间环节,理论上可以提高一个数量级的可靠性;然后就是减小UPS的体积和造价,直流UPS省略了逆变器和旁路装置,体积和造价当然降低。 相似文献