含间隙非线性弹性超材料的低频宽带机理北大核心CSCD

揭示了基于非线性混沌理论含间隙的非线性局域共振结构的低频宽带形成机理,提出了一类含间隙非线性局域共振结构设计的新理念.在该间隙非线性局域共振系统中,产生了非线性混沌现象,且这种非线性运动可以成功地改变振动噪声中的频谱结构,当系统运动进入混沌状态时,线性谱能量大大削弱,变成了一个连续的宽频谱,进而有效隔离低频线谱.有限元计算结果表明,正是这个间隙引起的非线性混沌现象导致了低频宽带的产生,且理论分析和有限元分析结果高度一致.因此,这类含间隙非线性局域共振弹性超材料结构的设计新思想为局域共振弹性超材料的发展开辟了新天地,且基于非线性混沌理论的低频带隙的形成机理为减振降噪应用研究奠定了非常重要的理论基础.

The Low-Frequency Broadband Mechanism of Nonlinear Elastic Metamaterials With Gaps

A new formation mechanism of the low-frequency broadband within gapped nonlinear local resonance structures was revealed based on the nonlinear chaos theory, and a novel concept for designing nonlinear local resonant structures with small gaps was further proposed. Due to the small gaps, the nonlinear chaos phenomenon occurs in the local resonance system, which can change the spectrum structure in vibration noise successfully, and the linear spectral energy greatly weakens and a continuous broad spectrum forms after chaotic motion, to effectively isolate the low-frequency spectrum. Most importantly, the finite element results show that, the nonlinearity of the small gap indeed leads to the low-frequency band-gap within the nonlinear local resonance. Therefore, the new idea for designing the nonlinear local resonance structure makes a new way to the development of local resonant elastic metamaterials, and the formation mechanism of low-frequency band-gap based on the nonlinear chaos theory lays a very important theoretical basis for vibration and noise reduction.