Design of the negative stiffness NegSV mechanism for structural vibration attenuation exploiting resonance

Abstract

The principle of influencing oscillation amplitudes of a primary system via secondary attachments can be enhanced with inclusion of nonlinear mechanisms towards energy absorption. This work exploits such a scheme, termed the NegSV device, which harnesses a geometrically nonlinear mechanism to create a negative stiffness system for vibration attenuation. The suggested device succeeds in shifting the stiffness characteristics of the primary system and, therefore, alters the overall dynamics without additional mass requirements. The top part of a structure can act as a resonator with respect to the lower by matching the respective resonant frequencies and thus directing energy at specified locations. Analytical solutions demonstrate the improvement of the dynamic performance of a system, which is modified with attachment of the proposed device. Physical testing on a 3 dimensional frame structure is further performed, via shaking table tests, with the proposed nonlinear mechanism mounted at the top storey of the experimental structure. The experiment reveals reduction of acceleration and inter-storey drift response at all levels below the retrofit, while the requirement of increased top-storey drifts is identified. Nonlinear finite element analyses are finally performed on a detailed numerical model, which demonstrate agreement with the experimental measurements and are exploited for additional improvement of the mechanism’s design. The proposed nonlinear device shows significant potential in attenuating structural vibration, while further offering the benefit of ease of installation.