Abstract
Magnetoactive membrane-type acoustic metamaterials are fabricated by coating a layer of magnetic nanoparticles on the polyethylene (PE) membranes and their vibration characters are investigated experimentally. From our experiments, we discovered that, under different magnetic fields by varying the distance between a magnet and the membranes, such membranes exhibit tunable vibration eigenfrequencies (the shift towards lower frequencies), which is caused by the variation of the effective mass density and effective tension coefficient resulted from the second derivative of the magnetic field. The strong magnetic force between the layer of magnetic nanoparticles and the magnet enhances the eigenfrequency shift. A spring oscillator model is proposed and it agrees well with the experimental results. We also experimentally observed that the vibration radius, effective mass density, and effective tension coefficient of the membranes can enormously affect the eigenfrequencies of the membranes. We believe that this type of metamaterials may open up some potential applications for acoustic devices with turntable vibration properties.
Highlights
Magnetoactive membrane-type acoustic metamaterials are fabricated by coating a layer of magnetic nanoparticles on the polyethylene (PE) membranes and their vibration characters are investigated experimentally
In this Letter, we demonstrate that by adjusting the relative position of a small magnet to the magnetic nanoparticle-enhanced diaphragm and the eigenfrequency of the diaphragm can shift towards lower frequencies, which results from the magnetic diaphragm experiencing varying magnetic field force while adjusting the distance between the magnet and diaphragm, which manipulates the effective mass density and effective elastic coefficient of the diaphragm
To better analyze the magnetic nanoparticle-enhanced diaphragm and magnet system, we introduce spring vibrators (Fig. 4a)
Summary
Magnetoactive membrane-type acoustic metamaterials are fabricated by coating a layer of magnetic nanoparticles on the polyethylene (PE) membranes and their vibration characters are investigated experimentally.
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