Design and development of advanced vibration and noise control devices using finite element analysis

Abstract

The high sound pressure levels (SPL's) radiated inside the payload fairing by its vibrating frame causes 40% of the satellite damage in the initial phases of the launch. Numerous experiments conducted on the advanced vibration absorbers such as the distributed vibration absorbers (DVA's) and the heterogeneous blankets (HG blankets) have shown great potential in reducing the vibration levels and the SPL's inside the payload fairings. Despite their good performance, little is known about the detailed mechanisms by which it is achieved. In addition, these vibration absorbers are currently empirically and experimentally designed which is a very cumbersome and time consuming process. To overcome the aforementioned limitations, there is a need for development of numerical techniques to understand the physics behind their functionality and to study the influence of the geometric layout or the choice of materials on their performance.

This work presents the development and validation of the finite element (FE) models to understand the physics behind the functionality of these vibration absorbers. The development of these FE models can be broadly classified in to three stages. In the first stage, the FE models of the individual components was developed and validated. In second stage, the fully coupled 3D-FE models of the advanced vibrations absorbers such as the DVA's and the HG blankets were validated. Finally, fully coupled 3D-FE models of these vibration absorbers coupled to the structural and acoustics domains were validated .

Parametric studies were performed on these fully coupled 3D-FE models in order to understand the effect of the variation in the material properties and geometrical configuration of these vibration absorbers on their response and also on their vibro-acoustic attenuation capabilities. The knowledge base built from the parametric studies was later used for the development of the optimized designs of these vibration absorbers.