非线性能量阱（Nonlinear Energy Sinks，简称NESs）属于被动结构控制技术，通过产生非线性回复力降低主体结构响应。该论文所研究的轨道非线性能量阱（简称轨道NES）是一种新型的NES，由轨道和附加质量组成。轨道与主体结构固定，质量块沿轨道运动，通过改变轨道形状，可产生所需的非线性回复力。首先，文中对轨道NES进行了理论分析，推导了轨道NES回复力表达式和附加轨道NES系统的运动方程。然后对一两自由度主体结构附加轨道NES进行了数值优化，优化后的轨道NES减振性能良好，且对主体结构刚度的变化具备较高的鲁棒性。但同时，研究发现轨道NES减振性能对输入能量大小较敏感。为改善其能量鲁棒性，文中又对NES阻尼进行了研究，分析其对轨道NES减振性能的影响。结果表明：当结构刚度和初始速度一定时，轨道NES阻尼存在最优值使结构减振效果最佳，即可以通过调整NES阻尼进一步改善其能量鲁棒性。
Abstract
Nonlinear energy sinks (NESs) are a type of passive mass dampers reducing structural responses of main bodies with their nonlinear restoring force. A new type of NES called track NES consisting of a specially shaped track fixed on a main body structure and an auxiliary mass moving along the track was proposed here. Nonlinear restoring force was produced by changing the shape of the track. Firstly, theoretical analysis was performed to derive the expression of track NES’s nonlinear restoring force and equations of motion for a structure with a track NES attached. Numerical optimization was then carried out for a 2-DOF main structure with a track NES attached. It was shown that the optimized track NES has a good vibration reduction performance, and better robustness against changes of the structural stiffness of the main structure; the performance of the track NES, however, is sensitive to input energy level. To improve its energy robustness, the damping of the track NES was further investigated. The results showed that when the stiffness of the structure and the initial velocity are constant, the damping of the track NES can be optimized to make the structure vibration attenuation effect optimal, i.e., adjusting its damping can improve the track NES’s energy robustness.
关键词
被动结构控制 /
非线性能量阱 /
数值模拟 /
阻尼 /
鲁棒性
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Key words
passive structural control /
nonlinear energy sink /
numerical simulation /
damping /
robustness
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