非均匀局域共振型声子晶体隔声特性研究

建立局域共振声子晶体单元结构模型,通过有限元方法研究了阵列排布、填充率排列及散射体厚度排列对非均匀声子晶体隔声特性的影响,以期使各类非均匀声子晶体结构在不同频段发挥隔声效果及减少隔声频段内的局部衰减.结果表明,散射体靠近入射方向的阵列排布具有较大的隔声量;填充率由中间列向两端递增的形式下局部衰减情况较少;散射体厚度由中间列向两边减小的排布适合中高频隔声,由中间列向两边增大的排布适合低频隔声;分别由铝振子、钢振子、铅振子构成的声子晶体在低频段具有相似的隔声特性,中高频处的隔声频段随着振子密度的增加向低频段移动.此结果为非均匀声子晶体获得良好降噪效果提供了理论支持.

Investigation on the Sound Insulation Properties of Non-uniform Local Resonant Phononic Crystals

Unit structure model of local resonant phononic crystals is set up.The effects of array configuration, filling rate arrangement and the arrangement of scatterer thickness are studied on the sound insulation properties of non-uniform phononic crystals (NPCs) through the finite element method.So that the structure of NPCs in different frequency bands play a good sound insulation effect and reduce the local attenuation in acoustic band.When the scatterers are close to the incident direction of array configuration, the NPCs have more sound insulation.If the filling rate increases from the middle column to the both sides, the NPCs have less local attenuation.With the scatterer thickness decreasing from the middle column to both sides, the NPCs are suitable for suppressing the medium-high frequency vibration or noise.On the contrary, another arrangement structure, with the scatterer thickness decreasing from the middle column to both sides, is suitable for low frequency noise isolation.The NPCs with the aluminum vibrator, the steel vibrator or the lead vibrator have similar sound insulation properties at low frequency, and the sound frequency band at medium and high frequencies is moved to low frequency with the increase of vibrator density.The obtained results may be provided as a theoretical guidance for the NPCs playing good effect on noise reduction.