Novel active and passive anti-vibration mountings

This paper investigates a novel design approach for a vibration isolator for use in space structures. The approach used can particularly be applicable for aerospace structures that support high precision instrumentation such as satellite payloads. The isolator is a space-frame structure that is folded in on itself to act as a mechanical filter over a defined frequency range. The absence of viscoelastic elements in such mounting makes the design suitable for use in a vacuum and in high temperature or harsh environments with no risk of drift in alignment of the structure. The design uses a Genetic Algorithm (GA) based geometric optimisation routine. A hybrid search of the objective function/feasibility problem is used for the search of a high dimensional design landscape with extensive, unknown and disjointed regions of feasibility. To complement the passive isolation system an active system is incorporated in the design to add damping. Experimental work to validate the feasibility of the approach is also presented. Using the techniques described here, 37.1% reduction in vibration transmissibility is achieved in an essentially undamped passively optimised structure and 50.7% when it is combined with an active element. It is shown here that the use of these novel anti-vibration mountings has no or little consequent weight and cost penalties whilst maintaining their effectiveness with the vibration levels. The approach should pave the way for the design of anti-vibration mountings that can be used between most pieces of equipment and their supporting structure