Magnetic-tunable sound absorber based on micro-perforated magnetorheological elastomer

A novel resonance sound absorber, whose resonant frequency characteristic can be varied by turning the external magnetic field, is constructed based on micro-perforated magnetorheological elastomer (MP-MRE). The influence of parameters, such as porosity, thickness, curing agent weight ratio and magnetic field intensity, are investigated to analyze the magneto-acoustic coupling property of MP-MRE sound absorber. By increasing the magnetic flux density, the resonant frequency of resonance sound absorber moves toward high frequency region. It is found the magnetic field-induced deformation of the MP-MRE and its pores affected the resonant frequency. When the magnetic flux density was increased from 0 to 132 mT, the maximum variation of the resonant frequency reached 304 Hz. Finally, originated from this unique magnetic controllability, the MP-MRE sound absorber shows broad potential in the tunable sound absorber at middle and low frequency range.