Design of quasi-zero-stiffness elastic diodes for low-frequency nonreciprocity through machine learning  

基于机器学习的低频非互易准零刚度弹性波二极管设计

作　　者：Junsen He Jiaxi Zhou Kai Wang Qiang Wang 何峻森;周加喜;王凯;王强(College of Mechanical and Vehicle Engineering,Hunan University,Changsha 410082,China;Key Laboratory of Advanced Design and Manufacturing Technology for Vehicle,Hunan University,Changsha 410082,China;Department of Mechanical Engineering,Hong Kong Polytechnic University,Hong Kong,China)

机构地区：[1]College of Mechanical and Vehicle Engineering,Hunan University,Changsha 410082,China [2]Key Laboratory of Advanced Design and Manufacturing Technology for Vehicle,Hunan University,Changsha 410082,China [3]Department of Mechanical Engineering,Hong Kong Polytechnic University,Hong Kong,China

出　　处：《Acta Mechanica Sinica》2024年第7期137-151,共15页力学学报（英文版）

基　　金：supported by the National Natural Science Foundation of China(Grant Nos.12122206,11972152,and 12272129);the Hong Kong Scholars Program(Grant No.XJ2022012).

摘　　要：Elastic diodes with nonreciprocity have the potential to enable unidirectional modulation of elastic waves.However,it is a challenge to achieve nonreciprocity at low frequencies(<100 Hz)using existing elastic diodes.This paper proposes a quasizero-stiffness(QZS)elastic diode to resolve such a tough issue and fulfill high-quality low-frequency nonreciprocity.The proposed elastic diode is invented by combining a QZS locally resonant metamaterial with a linear one,where the beneficial nonlinearity of the QZS metamaterial facilitates opening an amplitude-dependent band gap at very low frequencies.Firstly,the dispersion relation of the QZS metamaterial is derived theoretically based on the harmonic balance method(HBM).Then,the transmissibility of the QZS elastic diode in both the forward and backward directions is calculated through theoretical analyses and numerical simulations.Additionally,the influences of system parameters on the low-frequency nonreciprocal effect are discussed.The results indicate that considerable nonreciprocity is observed at a quite low frequency(e.g.,9 Hz),which is achieved by amplitude-dependent local resonance combined with interface reflection.Finally,a machine learning-based design optimization is introduced to evaluate and enhance the nonreciprocal effect of the QZS elastic diode.With the aid of machine learning(ML),the computational cost of predicting nonreciprocal effects during design optimization can be significantly reduced.Through design optimization,the nonreciprocal frequency bandwidth can be broadened while maintaining considerable isolation quality at low frequencies.具有非互易性的弹性波二极管可以用于弹性波单向调控.然而,利用已有的弹性波二极管在低频(<100 Hz)实现非互易性是一个挑战.本文提出了一种基于准零刚度的弹性波二极管来解决这一难题,实现低频高质量的非互易性.这种弹性波二极管通过将准零刚度局域共振超材料和线性局域共振超材料相结合来实现,其利用了准零刚度局域共振超材料可以在低频开辟振幅依赖带隙的有利非线性特性.首先,基于谐波平衡法推导了准零刚度超材料的色散关系.然后,通过理论分析和数值仿真计算了弹性波二极管的正向和反向传递率.接着讨论了结构参数对低频非互易效果的影响规律.结果表明,提出的弹性波二极管利用振幅依赖带隙结合界面反射的机制可以在低频实现高质量的非互易性.最后,介绍了一种基于机器学习的优化设计方法用于评估和增强弹性波二极管的非互易效果.利用这一方法预测非互易效果可以显著减少优化设计过程中的计算量.通过优化设计成功拓宽了弹性波二极管的非互易频率区间,同时在低频保持了足够的隔离质量.

关 键 词：NONRECIPROCITY LOW-FREQUENCY Elastic diode Quasi-zero-stiffness Nonlinear elastic metamaterials Machine learning 

分 类 号：TN312[电子电信—物理电子学] TP181[自动化与计算机技术—控制理论与控制工程]