新型周期阵列化电涡流动力吸振器的减振机理与优化设计方法

In order to meet the requirements of vibration and noise suppression in aircraft thin-walled structures, a new type of eddy current vibration absorber periodic array, which can be easily miniaturized, is proposed in the project. In the proposed scheme, damping, stiffness and mass are decoupled, and it can realize the associated tuning of design parameters and the maximization of effective bandwidth of absorber array. The project will combine the band-gap tuning theory developed from locally resonant acoustic metamaterial with the optimization design method of traditional absorber, and then apply in the design of eddy current vibration absorber periodic array. The influences of structural parameters, eddy-current damping parameter, and the scattering phase of elastic waves, continuous defect modes and the location of array on the vibration suppression performance will be clarified through the simulation and experiment. Research result will further enrich the design theory of vibration absorber. Introducing the theory of time-varying magnetic fields, establishing a force-electro-magneto-solid coupling model, and testing the eddy-current damping, the project will reveal the maximum energy dissipation capacity generated by the coupling role of mechanical motion and magnetic field, and determine the available design margin of eddy current damping. The propagation characteristics of typical aerospace thin-wall structure vibration waves will be further investigated and the structural own periodicity and vibration transmission characteristics will be used to enhance the ability of vibration energy capturer and dissipation of the proposed vibration absorber array. The ultimate goal is to develop a broadband vibration suppression method that is suitable for typical aerospace thin-wall structures, with good durability and engineering applicability.

针对典型航空薄壁结构的减振降噪需要，提出一种易于小型化的新型电涡流耗能型动力吸振器周期阵列设计方案。该方案可有效实现阻尼、刚度与质量环节的无耦合设计，为实施阵列设计参数最优同调，实现阵列吸振带宽最大化提供了可行的手段。项目将局域共振声学超材料中的带隙调控理论与吸振器设计的最优同调理论相结合，阐明结构参数、电涡流阻尼参数、弹性波相位散射、连续缺陷态调控、阵列布置等对电涡流耗能动力吸振器阵列性能的影响规律，进一步丰富动力吸振器的设计理论。引入时变磁场理论，建立力-电-磁-固耦合分析模型，并测试分析电涡流阻尼力，揭示电涡流耗能动力吸振器的最大动磁耦合耗能效应，阐明电涡流阻尼的可用设计裕度。进一步分析典型航空薄壁类结构振动的传播特征，充分利用加筋结构自身的周期性及振动传递特征，发挥吸振阵列的捕获和消耗振动能量的能力，发展出一种适用于典型航空薄壁结构，且具有良好耐久性和工程适用性的宽带减振方法。

由于振动频段宽、质量和体积限制严格、工作环境严苛多变，航空飞行器典型结构的振动控制成为工程上亟待解决的难点问题之一。通过引入基于电涡流阻尼效应的电涡流动力吸振器阵列，结合传统动力吸振器设计的最优同调理论以及局域共振子周期排布的带隙理论，对具有工程适用性的宽带减振方法进行丰富和发展。研究内容包括：1）传统构型电涡流阻尼器的建模及阻尼特性分析，建立了可以精确计算非线性电涡流阻尼力的力磁耦合有限元分析模型，并讨论了铜磁间隙、导体尺寸、永磁体尺寸、振动频率等参数对电涡流阻尼的影响规律，揭示了传统构型电涡流阻尼的可容设计边界；2）电涡流阻尼的频率非线性及其预计，建立了定量表征电涡流阻尼力及阻尼系数的科学评估方法，对目前普遍应用的线性电涡流阻尼进行了修正，揭示了电涡流阻尼关于频率出现非线性现象的原因；3）电涡流阻尼器的轻质小型化设计，提出了双环板式构型的电涡流阻尼器设计方案，当圆柱形永磁体的磁极半径大于10 mm时，阻尼器的耗能密度保持在1500 kN•s/m4以上，阻尼系数质量比保持在250 N•m/(s•kg)以上，相比于土木工程领域的复合板式构型，双环板式构型在电涡流阻尼器的小型化方面更具优势；4）电涡流动力吸振阵列的减振应用及优化设计方法，研究了阻尼等参数调制对含电涡流动力吸振阵列的梁、平板、加筋板结构减振频带的影响规律，进一步丰富了吸振阵列拓宽减振频带的优化设计方法。