声子晶体禁带特性及局域共振现象的试验研究

Experimental Study on Band Gap Properties and Local Resonance Phenomenon of Phononic Crystals

以弹性(亚克力柱/空气型)及粘弹性(硅橡胶/空气型)声子晶体为研究对象,研究了散射体填充率、形状、排列方式、材料性质、缺陷形式等对声子晶体禁带特性及局域共振现象的影响。结果表明:随着层数的增加,带隙频率逐渐靠近理论值,但达到一定层数后,其影响会减弱;与正方柱形比较,圆柱形声子晶体得到的带隙更宽,而与弹性声子晶体相比,粘弹性声子晶体更易得到低频宽带隙的效果;声子晶体晶体阵列个数对共振频率的影响并不大,而散射体形状、填充率、及材料性质对共振频率有一定影响,尤其是粘弹性材料对提高局域共振的品质因子有非常大的作用;多点缺陷的引入对缺陷局域模态的分离有一定贡献,但多点缺陷间隔较近时会降低局域模态的分离效果。

Based on the acrylic / air elastic phononic crystals and silicon rubber / air viscoelastic phononic crystals,the effects of volume fraction,shapes,sizes,materials properties,and defects on the band gap structures and local resonance modes were investigated. The results show that with the increase of sizes,the tested band gap frequencies are more close to the theoretical values,however,its effect is limited at the specific size. Compared with the square shape,the circular phononic crystal is more likely to get wider band gaps,while compared with the elastic phononic crystal,the viscoelastic phononic crystal is easier to get low-frequency and wider band gaps. The influence of size is not distinguished,while the effects of shapes, volume fraction, materials properties on the local resonance modes are quite significant,especially viscoelastic phononic crystals can help to improve the quality factor of local resonance modes. Multi-point defects can help to separate the local mode,however,the short distance between single defects would decrease the effect of splitting extent.