An Innovative Mechanical Filter for Seismic Isolation of Metallic Structures

Earthquakes are relevant source of stress for structures (buildings, bridges, etc.), since they may force structural components to work beyond their limits of elasticity, mining their integrity and stability. A possible solution to this problem is to filter the forcing signal by positioning a mechanical element between the site and the structure that, acting as low-pass filter, minimizes the energy transfer. This paper presents an innovative mechanical architecture to design low frequency broadband attenuators, capable to decouple the structure from the ground motion. This filter is based on the mechanism known as Watt’s Linkage, optimized for the design of low frequency broadband attenuators by geometric construction. This mechanical architecture, initially developed for the design of one-dimensional monolithic mechanical sensors, has recently been extended to the three-dimensional case, making possible its direct application as a large band low frequency filter for seismic isolation of structures. This innovative architecture will be presented with evidence of the results obtained from simulations and preliminary measurements on prototypes.