Active control of flexible cylinders undergoing vortex-induced vibrations using piezo stripe actuators
Date of Original Version
In this study, piezo stripe actuators were used to control the vibrations of a flexible cylinder undergoing underwater flow-induced vibrations. The piezo actuators were attached at the anti-nodes of a rectangular plastic beam and urethane rubber was used to mold the test model to have a circular cylinder shape. Forced base oscillation experiments were first carried out in air to characterize the system and piezo responses. Experiments were then performed in a recirculating water channel with the flexible cylinder in a uniform free stream, where the cylinder undergoes self-excitation due to vortex shedding in the wake and forced excitation due to the piezo actuators. The actuators were oriented to apply an excitation only in the in-line direction of the flow. In the tests, two separate cases were investigated. In the first case, the piezo actuators were activated at a flow speed corresponding to a flow-induced response with a spatial mode change, causing the cylinder to be excited with a higher mode, leading to a significantly smaller amplitude response than without the piezo actuation (vibration suppression). In the second case, piezo actuators were activated at a flow speed corresponding to a significant flow-induced amplitude increase. The interaction of the piezo forcing and the forced response of the cylinder results in a jump to the higher amplitude response regime (vibration enhancement). This study presents two important observations: (1) it is possible that piezo actuators can trip the response frequency to force the cylinder to oscillate with a different mode thus reducing the total response amplitude significantly, (2) it is also possible to prematurely increase the response amplitude for a particular flow speed (i.e. jumping from a lower branch to upper branch response).
Publication Title, e.g., Journal
Conference Proceedings of the Society for Experimental Mechanics Series
Gedikli, Ersegun D., David Chelidze, and Jason Dahl. "Active control of flexible cylinders undergoing vortex-induced vibrations using piezo stripe actuators." Conference Proceedings of the Society for Experimental Mechanics Series 6, (2019): 63-65. doi: 10.1007/978-3-319-74476-6_9.