Creating stopbands in structural vibration responses with 3D-printed tuned resonators

The potential for creating stopbands in the vibration response of mechanical structures with tuned local resonators is analyzed. A cantilevered steel beam is equipped with seven resonators. The resonators, consisting of PLA-printed springs and M8 nuts acting as masses, cover only a limited central portion of the beam. Experimental results with base excitation show a significant stopband in the transmissibility from shaker slip table to the free end of the beam. A reduced order model is derived from an FEM model of the beam using the classic Craig-Bampton method. Resonators are modeled using oscillators with a single degree of freedom, resulting in a strongly reduced and efficient structural model of the complete structure. The proposed resonator design and corresponding modeling allow for fast and accurate prediction of stopband design for mechanical structures, which are not periodic. The simulation results of the reduced model agree well with the full FEM analysis of the beam with FE-resonator models. Despite partial coverage of the beam by resonators, a distinct stopband can be attributed to these resonators covering one wavelength of the respective beam vibration mode.