Design Of Thick Tapered Micro-perforated Panel Absorber Based On Particle Swarm Optimization

Micro-perforated panel absorber is widely used with its good sound-absorptioncharacteristic. For a typical micro-perforated panel absorber, its pore size and thickness areboth controlled within millimeters. These paper-thin plates, because of their low intensity, aregenerally not suitable for civil, especially for interior decoration, so that the use ofmicro-perforated panel is restricted. In order to improve the strength of the panel, the moststraightforward approach is increasing the thickness of the panel, but the increase of thicknesswill bring the increase of and the weakening of matching capacity between microperforatedpanel’s acoustic impedance and air’s specific acoustic impedance and as a consequence, thesound-absorption performance will decrease. Based on the theoretical basis of themicro-perforated panel absorber, we numerically analyze the influence on thesound-absorption performance of micro-perforated panel absorber caused by aperture,thickness of the panel and the cavity, and perforation rate. As an improvement of thickmicro-perforated panel absorber, using tapered bore instead of traditional micro-perforatedpanel with cylindrical bore can improve the sound-absorption performance of thickmicro-perforated panel absorber. Then we analyze the sound-absorption characteristic of thicktapered micro-perforated panel absorber through establishing the numerical model. As thesound-absorption performance of thick tapered micro-perforated panel absorber is affected bymultiple parameters, different from the traditional method of determining the parameters, weapply the intelligent optimization algorithm-particle swarm optimization algorithm to get thesound-absorption structure with good performance. For detailed, establish the appropriateobjective function based on different design requirements and then optimize each parameters,resulting in getting thick tapered micro-perforated panel absorber with relatively good sound-absorption properties.This article mainly discusses two different thick tapered micro-perforated panel with thetapered bore and logarithmic bore. We optimized these two structures with single-parameter,two-parameter, three-parameter and four-parameter respectively. Single-parameteroptimization results show that the absorption coefficient of thick tapered micro-perforatedpanel absorber increased significantly after optimizing bore with large pore size; theabsorption structure got by using the thickness of bore with large pore size as parameter notonly can boost the maximum absorption coefficient, but also can ensure a constant resonancefrequency of the original thick micro-perforated panel absorber; after optimizing the thicknessof the cavity of large and small bore diameter respectively, the sound-absorption curve of sound-absorption structure was in the range of more saturated over the entire frequency;absorption properties are also improved compared with the three-parameter optimization afteroptimizing four parameters which are large bore diameter, small bore diameter, small boreperforation rate and the thickness of the cavity. Additionally, comparative analyzingabsorption properties of the tapered and logarithmic bore respectively, we found thatsound-absorption performance of logarithmic bore is better than that of tapered bore.However, because of structural complexity on logarithmic bore, the various factors should betaken into account in actual designing, so that optimum absorber can be chosen.