*Many different kinds of dynamic systems can be damaged if they are excited at the resonant frequencies. In this research, a novel method is developed to manipulate the natural frequencies of smart structures to eliminate or alleviate these detrimental effects. Because of the widespread usage of sandwich plates, this work considers a sandwich plate structure with Terfenol-D, which is a magnetostrictive material, comprising its middle layer.  The stiffness of this smart material changes based on the magnetic field that it is exposed to. Thus, the natural frequencies and resonances of the whole structure can be manipulated. Furthermore, in this research, the Terfenol-D in the middle layer is divided into five parallel sections so that each of them can be controlled separately. Therefore, it is possible to selectively activate portions of the magnetostrictive layers that run parallel along one of the plate’s directions to create periodic changes in the structure’s stiffness. Thus, the structure can be kept safe when excitations or disturbances approach one of its natural frequencies by activating sections to produce configurations that modify the natural frequencies. To this end, the natural frequencies of the structure are obtained analytically for a thin plate with Euler-Bernoulli equations. Then, the results are verified by the numerical results obtained using the finite element method. Moreover, activating certain portions of the Terfenol-D layer provides a periodic structure with a band gap that can play a crucial role in filtering out oscillatory motions with frequencies that falls within the band gap. The band gap of this structure has been examined in two periodic and two non-periodic conditions using finite element method.*


Band Gap and Natural Frequency Manipulation by Magnetostrictive Material in a Sandwich Plate Structure

Division / Sponsors: 
Dynamic Systems & Control (DSCD)

Paper Proceedings: https://asmedigitalcollection.asme.org/DSCC/DSCC2020/volume/84270

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