Indian Journal of Science and Technology

Abstract

Objective: The range of raw material used for the manufacture of Polyurethane using Polyol has grown enormously during the past fifty years. A wide range of products is now available, which allows the researchers to produce, collectively known as Polyurethane Foams as Porous Material. This paper examines the sound absorption properties of porous material from the view point of the manufacturer by the experimental and analysis way. Method/Analysis: In this experimental study, finite element method is well established in estimating acoustic transmission loss or sound absorption coefficient of a porous material. Impedance tube is used to measure the acoustic impedance of a sound absorbing porous material, with acoustic source at one end and an acoustic porous material. That is polyurethane foam at other end. There are two common methods used to measure the impedance value of the porous material. The first method involves a moveable microphone that transverses along the impedance tube and the second method is named as “transfer function” or “two-microphone”, the two microphone method is followed in this section. In this study, a 3D impedance tube is modelled using finite element software and the results will be compared with experimental data. Finding: The effort for this study determines a straight forward route to the production of Rigid Polyurethane foams through a direct reaction process. This system has potentially wide relevance as polyurethane foams. Here, an initial study has shown that using different way to calculate the sound absorption coefficient of a material, either by experimental way or by analysis using FEA software ansys. Application/ Improvement: Besides much other application, rigid polyurethane foam is used as acoustic layer in automobile industries, thermal insulation and as energy absorber medium in front bumper of auto motives. Hence by comparing the sound absorption coefficient value of the foam by the both experimental and analysis method we can improve the understanding level and efficiency of the rigid polyurethane foam. 
Keywords: 3D Modelling, Finite Element Analysis, Impedance Tube, Rigid Polyurethane Foam, Sound Absorption Coefficient