非光滑非线性能量阱的吸振效能及能量转移轨道控制研究

Nonlinear energy sink is a new kind of passive vibration absorber, which has promising application in aeronautics and astronautics fields because of its advantages such as broadband vibration suppression and light-weight. However, the absorber will suffer gradual or sudden failure under the excitation with wide-range variable amplitude due to the strongly nonlinear characteristics in itself, those phenomena severely restricting the application and development of the absorber. In this project, the law and dynamic mechanism of the evolution between strongly modulation response and higher branch response of energy transfer system will be deeply explored. The higher branch response will be eliminated and the absorption efficiency of the energy sink under large amplitude excitation will be enhanced by using non-smooth subassembly which is composed of linear and pure nonlinear spring elements and so on, the energy transfer between the primary system and energy sink will be controlled in the desired orbits by adjusting the parameters of the non-smooth subassembly. Then, the parallel non-smooth nonlinear energy sinks will be utilized to greatly improve the anti-vibration performance of the primary system, the coherent relationships between each energy sink of the parallel multiple energy sinks will be studied and the collaborative optimization method for the multiple energy sinks will be proposed. The key problems will be investigated by using the theoretical and experimental methods in the project, these research achievements can provide theoretical basis and data support for the design and optimization of non-smooth nonlinear energy sinks, and can promote the application of this kind of absorber in complex working environments.

非线性能量阱是一类新型被动式吸振器，由于具有宽频减振和轻质等优点，在航空航天领域具有广阔的应用前景。然而，非线性能量阱的强非线性特征会导致其在大范围变幅激励下发生渐进性或突发性失效，这严重制约了该类吸振器的应用和发展。本项目将深入探索能量转移系统强调制响应和高分支响应的演化规律及其动力学机理。利用线性和纯非线性弹簧元件等构成的非光滑组件消除系统高分支响应并提高能量阱在大幅激励环境下的吸振效能，通过调节非光滑组件参数将主振系统和能量阱之间的能量转移控制在预期的轨道上。进而，利用并联非光滑非线性能量阱实现大幅提高主振系统抗振性能的目的，研究并联多能量阱中各能量阱的相干关系并发展多能量阱的协同优化方法。本项目通过理论与实验相结合的方法对关键问题开展研究，取得的研究成果可以为非光滑类非线性能量阱的设计和优化提供理论依据和数据支持，并且能够推动该类吸振器在复杂工作环境中的应用。

纯非线性刚度能量阱具有轻质、宽频减振以及仅轻微改变被减振系统共振频率等显著优势，所以在诸多领域具有良好的应用前景。但是，该能量阱的强非线性特征所导致的分岔现象使其难以应用于激励比较复杂，尤其是激励幅值变化较大的场合。本项目主要研究了不同非光滑刚度特征对纯非线性刚度能量阱所诱发的高分支、强调制等特殊响应的调控作用并在此基础上设计出各类控制方案，分析了非光滑能量阱的并联使用对吸振性能的提升程度，利用优化算法完成了能量阱的参数优化。项目开展过程中，研究了不同的分段非线性形式对能量阱动力学特征的影响，综合考虑分岔控制能力、吸振能力、结构简易度等，确立了非光滑能量阱的第二阶段刚度为在纯非线性刚度上叠加线性刚度的方式，并利用分段线性阻尼和增加跨越分段边界时的碰撞耗能两种方法抑制分岔的发生，进而提出了碰弹强化能量阱和弹磁强化能量阱，研究发现，跨越分段边界时能量阱的速度骤减是高分支抑制的关键因素。研究了连接能量阱的矩形板的动力学响应，分析了矩形板的非线性因素对能量阱综合性能的影响，对连接于矩形板的纯非线性刚度能量阱和非光滑能量阱的动力学响应进行了对比分析。利用纯非线性刚度越小的能量阱产生分岔的激励幅值越大但吸振能力越低的机制，设计出刚度递减型非光滑能量阱，既保证了较小激励时的吸振能力又抑制了较大激励时分岔的发生。此外，利用并联耦合和多尺度串联的连接方式进一步提升了能量阱的综合性能。该项目为非线性能量阱的被动式分岔控制提供了新的方法，成果能够将非线性能量阱类装置在航空航天、航海、建筑等领域的应用推进一大步，并且，项目提出的分岔控制元件及其组合形式有较大潜力应用于其他的分岔控制场合。