舰船舱室减震降噪用泡沫金属铝的室温内耗性能研究

Study on damping property of foamed alumimum at ambienttemperature for damping and noise reducing of ship cabins

泡沫金属铝是一种新型船用减震降噪材料,在船舶舱室降噪中具有很好的工程实用价值。本文采用声频内耗仪测定了用熔体发泡法制备的工业用大规格泡沫金属铝在室温下的声频内耗,研究了泡沫金属铝在不同振幅和不同频率下的内耗特征,讨论了其内耗产生的机理。结果表明:泡沫金属铝具有较好的阻尼性能。在室温下的内耗随振幅的增加而增大,随频率的增加而减小。泡沫金属铝的内耗是因为其内部存在大量的孔洞,在交变载荷的作用下发生振动时,造成其内部应力应变分布不均匀,产生膨胀能和畸变能,使能量损耗。

Foamed aluminum is a new marine damping and noise reducing material. It is very convient and feasible in reducing noise of ship cabins for engineering structure.The damping property of foamed aluminum at different strain amplitudes and different frequencies is investigated through measuring the damping of the extensive foamed aluminum at ambient temperature and acoustic frequency with audio frequence internal friction analyzer.The mechanism of damping of foamed aluminum is also involved.The results show that foamed aluminum has good the damping property, Its internal friction is increased with the increase of amplitude and that is decreased with the increase of frequence.Foamed aluminum consists of an integrity of aluminum framework and pores.The vibration of foamed aluminum under the action of an alternately stress,will result in non uniform the distribution of the stress and strain in foamed aluminum,which will cause the dilation and distortion of pores to generate the dilatation and distortion energy,resulting in an energy loss.