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Experimental assessment of an ultrasonic band gap in a periodic two-dimensional composite

An experimentally observed ultrasonic full band-gap in periodic two dimensional composites is described. The composite structure consists of an aluminum alloy plate with a square periodic arrangement of cylindrical holes filled with mercury. The band-gap found has a bandwidth of about 600 kHz around the first network resonance (750 kHz) along the [100] direction. The experimental test was performed by means of the through-transmission technique, exciting the structure with longitudinal waves. Moreover, different acoustic scannings of the vibration amplitude were also performed.