43. A Numerical Investigation of a Gravity-Compensated Nonlinear Energy Sink for the Passive Control of Flooring Systems

Flooring systems are subjected to a variety of human-induced and mechanically-induced loads which can vary in amplitude, frequency, and location. Furthermore, the properties of flooring systems and the acceptable levels of vibration can change during the life of a building as it transitions between multiple different uses. Tuned mass dampers (TMDs) can be effective at controlling floor vibration; however, their effectiveness is limited because TMDs must be tuned and can only effectively control vibrations across a narrow band of frequencies. Recently, a passive mass damper, known as a gravity-compensated nonlinear energy sink (GCNES), was proposed to mitigate vertical vibrations. The unique geometric nonlinearity used to produce this device’s stiffness element compensates for the vertical offset resulting from the weight of the device and allows it to dynamically achieve a cubic nonlinearity. This strong nonlinearity allows the GCNES to interact with the flooring system across a broad range of frequencies. In this paper, a numerical model of a flooring system with a GCNES attached is developed. This model is then used to investigate the effectiveness of the GCNES, in comparison to the TMD, at controlling floor vibrations. The results of this study show that, while the TMD is more effective when mitigating excitations at the particular frequency it is tuned to, the GCNES can provide effective vibration control across a wide range of frequencies near the system’s resonance point.