Study on Sound Insulation Properties of Composite Laminated Structures

Abstract

The research principally consists of the qualitative and quantitative analysis of sound insulation performance of laminate structure. Composite materials have been widely used in aerospace, marine, transportation and other engineering industries due to their light weight, good mechanical properties and high temperature and corrosion resistance. On the Boeing 787 Dreamliner, more than half mass is taken by composite materials which are distributed over the wings, the empennage and the engine nacelles. As the extensive usage of composite laminated plate in the aeronautic domain, people began to focus on their acoustic performance. The mass law was proposed in the end of 19 th century (Rayleigh, 1878). It has been proved that the sound insulation is linearly dependent on the density and excitation frequency. The mass law has been widely applied and validated in different circumstances over the past century. In the middle of 20 th century, the occurrence of the theory of coincidence effect (Cremer, 1942) gave a theoretical explanation of the reduction of the acoustic performance in the middle and high band. These theories have formed the very base of modern acoustics. With the advent of computers, the study of the acoustic properties of materials has entered the era of simulation. The simulation-based studies principally use finite element analysis and statistical energy analysis. For example, the study of point-support plate structure (Shorter et al., 2005), the study of inlaid finite laminated plate (Li and Zhao, 2001) and the study of sound insulation performance of glass fibre reinforced resin-based materials with steel balls inside (Yan and Huang, 2016). Many studies have been carried out on composite laminates materials, while rare conclusion or law of laminate manner constated from researches. At present,

Calculation of Sound Insulation of Softwood Samples at Normal Incidence and Comparison With Experimental Data

“…1.063074 of which the percentage was over 90% Hou 2001, Watanabe andNorimoto 2000). The gas permeability in softwood was closely related with its flowing characteristics and rules in tracheids (Zhan 2014, Liu et al 2012. In hence, it was significance to investigate the sound insulation of wood defined as the porous structure material.…”