Dynamic behaviour of sandwich structure containing spring-mass resonators

The behaviour of wave propagation in a sandwich beam with internal resonators is studied analytically and experimentally. It is found that, with the occurrence of a bandgap, waves generated by actuations in certain frequency range are forbidden to propagate into the sandwich beam without attenuation. By tailoring the local resonance frequency of the resonator, the range and the location of the bandgap can be selected. Also, from the experimental and FEA results, it is seen that waves can be significantly attenuated in a sandwich beam with a finite number of internal resonators if the forcing frequency is near the local resonance frequency. It is concluded that the resonators can be used as a mechanism for suppressing the flexural motion in a sandwich beam.