A wave approach to structural transmission loss in periodic structures: Thin beam case

When new building systems are developed, these are often lightweight constructions with a periodical set of stiffeners, developed for use in load-bearing structures and dwellings. One of the main drawbacks of this type of building systems is the sound insulation, where flanking transmission is an important issue. A prediction model for flanking transmission of lightweight building structures is thus under development. This paper is a theoretical study of the structural transmission coefficient of a junction, using a propagating wave approach. Free waves travel in the periodic wave-medium. The periodic resilient elements consist of rotation and displacement springs. The free waves meet a discontinuity (or junction), and the power transmitted through the discontinuity is then studied. The discontinuity consists of a mechanical coupling and point mass load. The model is analytic and deterministic, and makes use of a spatial Fourier transform wave approach for periodic structures. The approach is intended for flanking transmission of lightweight building structures, but it is also applicable for structures such as ships and aircraft. Numerical results are presented and discussed. It is concluded that the periodic nature of the wave media affects the power transmitted through a discontinuity