Active control of vortex shedding and galloping induced vibrations in an auxetic aeroelastic structure

In this study, an aeroelastic smart structure exhibiting regular vibrations induced by vortex shedding was developed. Two types of beam elements—straight and auxetic—were fabricated using additive manufacturing techniques. The structure incorporates beam elements along with a flow-disturbing geometry designed to induce galloping behavior. The damping and stiffness properties of the fabricated beams were determined experimentally. Additionally, the natural frequencies of the structure were identified through free, forced, and modal vibration tests and validated by comparing the results with numerical simulations. Piezoelectric actuators made from the same material were bonded to both beam types and used to suppress vibrations through a feedback control loop. Displacement feedback for the control system was provided by a laser displacement sensor measuring the vibrations of the aeroelastic structure. To induce continuous vibrations, an external aerodynamic load was applied using a centrifugal fan. A proportional–integral–derivative controller was then designed and implemented to control the vibrations. Vibration control experiments were conducted for both beam types, with and without control activated. Displacement of the beams and the control voltages applied to the actuators were recorded as functions of time. When examining the control experiment results, the control effort used to suppress the vibrations of the straight beam is higher compared to the auxetic beam. This is consistent with the results obtained from the mechanical properties, free vibration responses, damping factor, and natural frequency values derived from the experiments. The experimental results highlight the influence of varying beam stiffness on the effectiveness of vibration control.