Passive Control of Multi-Jointed Structures

Abstract

Reducing the amplitude of structural response generated by noise sources such as machine vibrations using passive control measures is of interest to design engineers. This study will focus on the role of joints in multi-jointed structures in the passive control of structural response. In a multi-jointed structure, joints play a major role in the response of the structure. First, joints regulate the equilibrium of the whole structure. In such a role, they can act, for example, to transform a pure axial wave in a horizontal member in the structure into a pure flexural wave in a vertical member connected to it at a joint. Second, they are the “recipients” of the noise sources from the secondary beams and floors of the structure. In such a role, joints act as a filter between the noise source and the rest of the structure. These two roles point to the possibility of modifying joints so as to passively control the response of a multi-jointed structure. In this study, the addition of energy loss mechanisms, which are concentrated at the joints is evaluated. These energy loss mechanisms include adding filler materials with high loss factor. The different parameters affecting the structural response will be evaluated. These parameters include the amount of added material to the joints, relative loss factors of both structure and the added material and the degree of reductions in structural responses. In all the cases studied, a consideration of the practical engineering detailing of such systems will be discussed.