The research objective of this collaborative project by University of Connecticut, University of Tennessee and Tennessee State University is to create new theories and a potentially transformative technology to effectively control the gear system-induced vibration propagation. In gear systems, multi-tonal vibrations are induced as a result of parametric variations in tooth mesh stiffness caused by kinematic variations in the number of teeth in contact and tooth flexibility. In this project, we plan to develop a multi-layered, hybrid control methodology to enable multi-tonal vibration suppression of parametric time-varying gear system dynamics via simultaneous passive isolation and active control. Specifically, we will develop bi-periodic extension-twist coupled piezoelectric / composite struts with tunable frequency stop-bands to block high frequency vibration propagation, and in the meantime employ the piezoelectric transducers in the struts to realize a dual-loop adaptive feedforward / time-varying feedback control strategy based on Floquet decomposition that provides active suppression of self-exited vibrations. With these innovations, the new methodology will rigorously address the major challenges in gear system vibration control, e.g. wide spectrum multi-tonal vibrations, time-varying dynamics with parametric excitations, and non-stationary responses.
Gears are critical components in many energy, aircraft, automobile, and marine/ship systems. If successful, the outcome of this research can lead to not only increased durability, reliability and efficiency of those systems, but also improved human operating and living environment. Particularly, reduction of gear-induced vibration and associated noise emissions can play a critical role in wind energy development. By carrying out the educational tasks, the PIs will disseminate the research findings through classroom teaching, community outreach, and involving under-represented and minority group students in capstone projects, thereby contributing significantly to workforce training.