半主动式薄膜型声学超材料超低频隔声特性研究

Study on Ultra-low Frequency Sound Insulation Characteristics of Semi-active Membrane Type Acoustic Metamaterials

针对变电站50 Hz的超低频噪声较难控制的特点,设计一种半主动式薄膜型声学超材料,通过仿真模拟计算其隔声特性。该材料以钕铁硼磁铁作为中心质量块负载于边界固定的橡胶薄膜上,并装配通电螺线管作为半主动控制系统。通过仿真模拟及数值分析手段对其隔声特性进行研究。通过改变电流强度准确控制中心钕铁硼磁铁质量块的受力,最终改变薄膜张力,实现隔声峰频率的控制,与一般的薄膜声学超材料相比,其具有缓解薄膜材料疲劳等优点;并对薄膜厚度以及质量块厚度、大小对薄膜型声学超材料声学特性的影响进行研究。仿真结果表明:该材料对于50 Hz的超低频噪声隔声量达到130 dB,具有优良的隔声性能。

A semi-active membrane type acoustic metamaterial is designed for the control of 50 Hz ultra-low frequency noise in substations,and its sound insulation characteristics are calculated by simulation.The material is loaded with an NdFeB magnet as the central mass block on the rubber film with the edge fixed,and equipped with an energized solenoid to form a semi-active control system.Its sound insulation characteristics are investigated by simulation and numerical analysis.By changing the current intensity,the force applied on the central magnet block is precisely controlled,resulting in a change of film tension and achieving the control of the isolation peak frequency.Compared with conventional thin film acoustic metamaterials,this material has the advantage of alleviating the fatigue failure of thin film materials.The effects of film thickness as well as mass block thickness and size on the acoustic properties of thin-film type acoustic metamaterials are investigated.The simulation results show that the material has excellent sound insulation performance with a 130 dB sound insulation capacity for ultralow frequency noise of 50 Hz.