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设计屏蔽目的是减小噪声能量的传播。掌握屏蔽材料的阻抗特性,合理地利用这个特性,就能设计出高性能的屏蔽。从阻抗对声波的传导及反射的关系,将不同阻抗的介质设计“错配”,要比单一材料同样厚度的屏障能有更高的隔声效果。应用Snell定律对二种阻抗差很大的材料将界面安排成一定角度;应用声传导的质量效应,选用表面质量大的材料作屏蔽,都能使屏蔽区的噪声级有明显降低。
The purpose of design shielding is to reduce the propagation of noise energy. Grasp the impedance characteristics of shielding materials, the rational use of this feature, we can design a high-performance shielding. From the relationship between the impedance and the acoustic wave conduction and reflection, the design of the media with different impedances is “mismatched” and can provide a higher sound insulation effect than the barrier with the same thickness of a single material. Applying Snell’s law to two kinds of materials with great difference of impedance, the interface is arranged at a certain angle; using the acoustic effect of mass transfer, selecting materials with large surface mass for shielding can significantly reduce the noise level in the shielding area.