Abstract

Machines and other driving components like compressors or fans usually generate vibrations which frequently lead to acoustic noise. Flexible structures equipped with acoustic black holes minimise acoustic radiation by confining structural vibrations locally. One main restriction of its usage in the broad engineering field is its limited effectiveness at low frequencies. Recent investigations shifted the frequency range of attenuation successfully down to 1500 Hz. Moving the existing designs towards an even lower frequency demands a large structure. However, in general, sufficient space is often not available in machines and facilities. We propose a new design that enables a geometrically compact and simultaneously broadband vibration attenuation in the low-frequency below to 100 Hz: stacked wedges. The proposed design is calculated and optimised numerically by combining CAD and finite element calculations. The influence of geometrical parameters on the effectiveness of vibration attenuation is analysed with the help of transfer functions and dispersion curves. Successful designs of multi-stacked wedges at different lengths confirm their effectiveness at low frequency.

Graphical abstract

摘要

机器和其他驱动部件（例如压缩机或风扇）通常会产生振动，从而经常导致噪音。配备声学黑洞的柔性结构通过局部限制结构振动来最大限度地减少声辐射。其在广泛的工程领域中使用的一个主要限制是其在低频下的有效性有限。最近的研究成功地将衰减频率范围降低至 1500 Hz。将现有设计转向更低的频率需要大型结构。然而，一般来说，机器和设施往往没有足够的空间。我们提出了一种新设计，可以在低于 100 Hz 的低频中实现几何紧凑且同时宽带振动衰减：堆叠楔块。所提出的设计通过结合 CAD 和有限元计算进行数值计算和优化。借助传递函数和频散曲线分析了几何参数对减振效果的影响。不同长度的多层堆叠楔形物的成功设计证实了它们在低频下的有效性。

图形概要