In this paper, the acoustical treatment of double-panel structures lined with poroelatic materials is predicted using analytical method in order to study the effective usage of the various boundary conditions of porous layer and to identify the effective parameters on the transmission loss of the multilayer systems. Therefore, inertia and viscous coupling along with thermal and elastic coupling...

Broadband noise in a vehicle’s interior is an important issue because of its negative impact on the passengers’ comfort and wellbeing. The perception of this broadband noise can increase due to the use of new, less noisy drive concepts and the accompanying loss of masking noise components. This contribution focuses on the reduction of the transmission of external broadband disturbances through ...

The sound transmission loss of lightweight structures can be increased by the application of facing formworks. In the aircraft industry this task is accomplished by means of sidewall panels (linings) mounted on the primary fuselage structure of an aircraft. At low frequencies (< 1000Hz), however, the sound transmission loss is dominated by the so-called mass-law which prescribes an inverse rela...

The acoustic performance of passive or active panel structures is usually tested in sound transmission loss facilities. A reverberant sending room, equipped with one or a number of independent sound sources, is used to generate a diffuse sound field excitation which acts as a disturbance source on the structure under investigation. The spatial correlation and coherence of such a synthesized non...

The purpose of this paper is to introduce the concept of soft double fuzzy semi-topogenous order. Firstly, we give the definition of soft double fuzzy semi-topogenous order. Secondly, we induce a soft double fuzzy topology from a given soft double fuzzy semi-topogenous order by using soft double fuzzy interior operator.

the existence of some geometrically imperfect members, like initial curvature in a double layer space structures with hundreds or thousands of members is almost inevitable. these imperfections give rise to loss of load bearing capacity of double layer space structures. to evaluate the effect of initial member imperfection on load bearing capacity of double layer space structures and their failu...

Several different factors have come together to make the topic of this conference, “Investing Today for the World of Tomorrow,” a timely one for any developed economy, and particularly for Germany. Among them are increased global competition, a seemingly rapid pace of technological change, especially in information-based and network industries, and, in Germany, the need to absorb and restructur...

We introduce Poisson double algebroids, and the equivalent concept of Lie bialgebroid, which arise as second-order infinitesimal counterparts groupoids. develop their underlying theory, showing how these objects are related by differentiation integration. use results to revisit 2-bialgebras means structures.

The paper addresses the active control of the sound transmission through a double panel partition. A literature survey indicates that active cavity control is much more efficient than active structural control. The vibro-acoustic behaviour of the double wall is analysed in light of this observation. This analysis shows that the sound transmission through the double panel is larger than that thr...