用于汽车低频振动控制的局域共振声子晶体*

低频振动的控制是评估汽车舒适性的重要指标。针对汽车板件结构的低频振动控制问题,提出了一种基于局域共振机理的新型准二维声子晶体板。其结构由单侧复合圆柱共振单元周期排布在基板上构成。通过有限元方法得到了该结构的带隙特性,并结合其振型和传输谱分析了低频完全带隙的形成机理。研究表明,不同形式的板振动模式与圆柱共振单元的局域共振模式相互耦合形成面内带隙与面外带隙,两者叠加形成完全带隙。进一步研究发现,通过改变结构的材料和尺寸参数可以将共振带隙调节到满足实际应用要求的极低频范围,可在低于100 Hz的频段形成完全带隙,并可在更宽的频带内抑制z方向振动的弯曲波,为声子晶体在车身板件减振中的实际应用提供了依据。

A locally-resonant phononic crystal for low-frequency vibration control of vehicles

Low-frequency vibration control is an important indicator to evaluate the comfort of the vehicles. In this paper, based on the localized resonant mechanism, a quasi-two-dimensional phononic plate has been designed to suppress the propagation of the low-frequency vibration in a vehicle. The system is composed of single-sided composite cylindrical resonance units which are periodically arranged on the substrate. The bandgap of the structure is obtained with Finite Element Method and the formation mechanism is clarified by analyzing the vibration modes and transmission spectra. It is shown that, the coupling of different vibration modes of the plate and localized resonant modes of the cylindrical units forms the in-plane bandgap and out-of-plane bandgap, and superposition of the two bandgaps forms a complete bandgap. Moreover, by tuning the parameters of materials or dimensions, the system can achieve bandgaps in frequency ranges which are required in realistic application, i.e., in frequencies lower than 100 Hz. Moreover, the designed structure can suppress the vibration of bending waves in z-direction in wider frequency range, which supplies more application opportunities to control vibration in vehicle-body panels.