Research about Flexible PDMS Micro-Perforated Panel Based on MEMS Silicon Mold

Abstract

Micro-perforated panel (MPP) is known for its remarkable noise absorption capability and has been studied and developed for decades. Although the panel and cavity walls of traditional MPP are rigid, some previous works have shown that the absorption bandwidth of flexible MPP can be improved by the vibration of the panel. But this result is only tested at low frequencies. In this paper, the flexible MPP aiming at high frequency range is studied under a control experiment. But the perforations of high frequency MPP are in the range of micron and difficult to be fabricated in traditional mechanical methods. A new process, based on MEMS silicon mold technology and PDMS casting method, is developed to meet this challenge. Experimental results show that the noise absorption bandwidth of flexible MPP does get widened conspicuously only at a little sacrifice of absorption peak.

A New Sound Absorption Improvement Strategy under Low Frequency for a Rigid Micro-perforated Panel Absorbers

“…This is due to the fact that lower perforation ratio of 3# flexible MPPs result in large acoustic mass, which makes the absorption frequency band relatively narrow compared with 1# rigid MPPs. Based on the Haoyue Ping [12]'s work, the sound absorption peak of flexible MPPs drops from 99.8% to 94.6% and shifts to lower frequency from 3 KHz to 2.5 KHz compared with the same structure rigid MPPs, and the noise absorption bandwidth of flexible MPPs does get widened conspicuously and the sound absorption coefficients at 1.5 KHz and 6 KHz get improved significantly as illustrated in Fig. 4(d).…”

“…For the experimental investigation, MEMS technology or needle-punching and PDMS casting method were applied to fabricate the flexible MPPs, a rigid MPPs was fulfilled by means of machining. The MPPs made from PDMS is widely applied in micro-fluidic chips to fabricate structures on microscale [12]. PDMS is highly transparent , and is characterized by viscoelastic, which could flow into any structure and be shaped in mold easily.…”

“…According to the equivalent circuit in Fig. 2(b), the normalized specific acoustic impedance of the whole structure can be calculated by 12…”