Akademik Veri Yönetim Sistemi
Journal of Vibration Engineering and Technologies, cilt.13, sa.7, 2025 (SCI-Expanded)
Purpose: This article investigates a new concept of active metamaterial cell that does not transmit vibrations in a reciprocal manner. Expanding the range of affected frequencies of vibroacoustic metamaterials stands as a challenge as broadband efficiency is often traded with stability and robustness of the active structure. In that regard, active waveguides utilizing dislocated sensor-actuator pairs using either pure velocity or pure displacement feedback show promising progress. However, only limited reciprocity loss was present at low frequencies, if the velocity feedback is used, or at high frequencies, if displacement feedback is used. Methods: This article focuses on a conceptual development and experimental validation of an active metamaterial cell that utilizes a combination of displacement and velocity feedback to obtain a nonreciprocal response over both low and high frequencies. The study is focused on a 2 Degree-Of-Freedom lumped parameter mechanical system coupled with electromechanical transducers. Despite the fact that velocity and displacement feedbacks have opposing stability conditions to each other when analysed separately, significant stability margin of the combined velocity and displacement feedback signal is rigorously determined theoretically and experimentally. Results: The results demonstrate that the proposed active waveguide induces significantly different frequency response functions for opposite propagation directions, with amplitude differences peaking around 30 dB over a frequency band exceeding 2900 Hz. Conclusion: The results shown confirm that the combination of velocity and displacement feedback in dislocated transducer arrangement provide broadband nonreciprocal vibration transmission. This further supports the possibility of practical implementation of the proposed control scheme in prospective active acoustic metamaterials for nonreciprocal sound transmission anticipated in future work.