薄膜型声学超材料对低频振动的隔声特性分析*

高效共振混合机工作频率为60 Hz，且系统处于共振，产生较大低频噪声。针对振动机械产生的有害噪声，分析了高效共振混合机低频高加速度共振混合过程的特点，得到了60 Hz低频声波穿透力强特点，相比传统的以吸声材料构建的50~100 mm厚度、隔声效果小于10 dB的隔声罩，分析了薄膜型声学超材料在低频减振降噪中的隔声特性。通过多物理场仿真分析，60 Hz时隔声量为31.4 dB，确定了硅橡胶弹性薄膜的预应力和质量块的面密度；采用3D打印机快速成型技术，构建了隔声实验装置，分析了独立隔声单元、面密度、薄膜尺寸等隔声特性规律。基于人耳在实际环境中感受到的噪声强度，提出了噪声衰减量和插入损失的分析方法，在距离声源380 mm和1000 mm的位置，60 Hz时隔声量分别为27 dB和38 dB。研究成果丰富了低频隔声特性理论，为薄膜型声学超材料的工程设计和优化提供了技术支撑。

Analysis of Sound Insulation Characteristics of Membrane-type Acoustic Meta-materials in Low Frequency Vibration

The super efficient mixer works at a low frequency of 60 Hz and the system is in resonance, which produces relatively large low frequency noise. Aiming at the harmful noise generated by the vibrating machinery, this paper firstly analyzes the working principle of the low-frequency and high-acceleration resonance mixing process of the resonance acoustic mixer, and the characteristics of strong penetration of 60 Hz low-frequency sound waves are obtained. The traditional 50-100 mm sound insulation cover constructed with sound-absorbing materials has a sound insulation effect of less than 10 dB. In this paper, the sound insulation characteristics of the membrane-type acoustic meta-materials in low-frequency vibration and noise reduction are analyzed. Through multiphysics simulation analysis, the 60 Hz sound insulation is 31.4 dB, and the prestress of the silicone rubber elastic film and the areal density of the mass block are determined. Using 3D printer rapid prototyping technology, a sound insulation experimental device was constructed. This paper analyzes the laws of sound insulation characteristics such as independent sound insulation units, areal density, and film size. Based on the noise intensity felt by the human ear in the actual environment, an analysis method of noise attenuation and insertion loss is proposed. At a distance of 380 mm and 1000 mm from the sound source, the sound insulation at 60 Hz is 27 dB and 38 dB respectively. The research results enrich the theory of low-frequency sound insulation characteristics and provide a technical support for the engineering design and optimization of membrane-type acoustic meta-materials.