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最近研究表明,将声子晶体中的局域共振现象引入到水下吸声材料的设计中,可以观察到由局域共振引起的低频声吸收现象.为了进一步揭示局域共振低频吸声机理并获得更优的水下低频声吸收性能,研究了内嵌不同形状散射子的黏弹性声学覆盖层.利用晶格和散射子在空间排布的对称性,传统有限元方法得到简化,从而节约了计算时间和存储空间,并通过将简化有限元法计算得到的结果与传统有限元法计算的结果进行对比,验证了简化有限元方法的正确性.结合位移云纹图,考察了特定频率点上振动模态与相应的局域共振吸声峰之间的关系,揭示了内嵌圆柱形散射子的黏弹性覆盖层的吸声机理.进一步讨论了相同体积下不同形状的圆柱形散射子对黏弹性覆盖层吸声性能的影响,给出了提升覆盖层低频吸声性能的优化思路.通过讨论不同芯体材质对内嵌圆柱形散射子的黏弹性覆盖层吸声性能的影响,找到了改变第一共振峰位置的方法,从而可以通过调整第一共振峰来实现特定频率范围内的宽带吸声.
Recent studies have shown that local resonance in phononic crystals can be introduced into the design of underwater sound-absorbing materials to observe low-frequency acoustic absorption caused by local resonance. In order to further reveal the low-frequency sound absorption mechanism of local resonance Get better underwater low-frequency acoustic absorption performance, and study the viscoelastic acoustic cover embedded with different shaped scatterers.Using the symmetry of the lattice and scatterer in the spatial arrangement, the traditional finite element method is simplified, thus saving The time and the storage space were calculated and compared with the results of the traditional finite element method through the simplified finite element method to verify the correctness of the simplified finite element method.Combined with the displacement moiré diagram, The relationship between the vibrational modes and the corresponding local resonant absorption peaks reveals the sound absorption mechanism of the viscoelastic coating with embedded cylindrical scatterers.The viscoelasticity of different shapes of cylindrical scatterers under the same volume is also discussed The influence of the sound-absorbing performance of the overburden, the optimization idea of improving the low-frequency sound-absorbing performance of the overburden is given.By discussing the effect of different core materials on the embedded cylindrical scatterer Effect of absorption properties of the elastic covering layer, a method to find the position change of the first formant, so that broadband can be achieved within a specific frequency range of sound absorption by adjusting the first formant.