Research On Acoustic Properties Of Plywood CRH3 Flooring

This article mainly discusses about acoustic properties of plywood and four factors that influence acoustic absorptivity and acoustical reduction coefficient of plywood. That are veneer species of plywood, thickness of plywood, water ratio of plywood and glue spread of plywood. Also this paper discusses about acoustic properties and mechanism action of several composite materials based on plywood. Acoustic properties researches of fiber reinforced material, dope-dyed fibers with plywood composite material and nonwovens composited with plywood. Analysis of variance and analysis of range are carried out on research results, aimed at doing systematic acoustic research for plywood, through the experimental results to determine the acoustic performances improved plywood materials and technology.In research of factors influencing acoustic properties, veneer species and thickness of plywood have notable influence. Its acoustical properties increases with the thickness; moisture content has some influence on acoustic properties, but has not notable impact on acoustical reduction coefficient; glue spread amounts for plywood have not influenced its acoustic properties. So thickness and density for plywood are the most important factors.In the research of modifying of plywood, use fiber strengthen to improve acoustic properties. During research glass fiber, dope-dyed fiber and nonwovens are adopted. We find that nonwovens with plywood improves the acoustic properties and reached a better bonding strength. Based on these experiment and results, And through orthogonal test discusses structure, thickness, fiber mesh of non-woven/plywood composite that influences acoustic properties. And the best condition for absorption coefficient is Non-woven fabrics for 120 of mesh,14 layers thickness of plywood when making multilayer plywood, nonwovens, veneer for gluing together. Average absorption coefficient can achieve 0.175, average acoustical reduction coefficient for 38dB.