IN-VACUO STRUCTURED FABRIC TUNEABLE VIBRATION ABSORBER

This paper is focussed on a new tuneable vibration absorber, which is formed by one or multiple strips of a structured fabrics wrapped in a vacuum bag. The middle span of this beam-like structure is fixed to a post such that its flexural vibration is controlled by a flapping fundamental natural mode, whose natural frequency is varied by changing the level of vacuum in the bag. At first, the study presents a parametric analysis to show how the bending stiffness and damping properties of the beam-like structure vary with respect to the vacuum level in the bag and with respect to the grain geometry and number of fabric layers. Then, it provides a thorough analysis of the absorber base mechanical impedance frequency response function with respect to the level of vacuum and the type of structured fabric. The preliminary experimental results show that the fundamental natural frequency of the proposed tuneable vibration absorber can be varied over a wide frequency range such that it can be effectively used to track changes in the tonal excitations or changes in the resonant response of the hosting structure.