Design and experimental analysis of a pneumatic Nonlinear Energy Sink

Nonlinear Energy Sinks (NESs) have been the object of several theoretical and experimental studies over the past decade, as a subcategory of nonlinear vibration absorbers. The present work illustrates the theoretical design and experimental realisation of a pneumatic Nonlinear Energy Sink (so-called AirNES). The nonlinear elastic force of the NES is provided by a circular membrane. This membrane is fully bonded and delimits two air chambers, linked together via a pipeline. The nonlinear damping of the NES is ensured by the flow of the air at high velocity inside the pipeline. Thanks to this design, the AirNES is embedded on a one degree of freedom linear dynamic system to evaluate its performances. The Target Energy Transfer (TET) from primary system to the NES, as well as different response regimes such as the Strongly Modulated Regime (SMR), are experimentally observed. Additional experiments demonstrate the role of the air in the damping of the prototype. A simple modeling of the AirNES is proposed to ensure a quasi-analytical design of the prototype, including the analytical calculation of the damping. Simulations are then compared to the experiments and show good qualitative correlations as well as some discrepancies between model and reality.