Tubular multi-level resonator cored composite sandwich structures for vibration suppression and load bearing

In this work, a novel tubular multi-level resonator cored composite sandwich structure (TMRSS) filled with polymethacrylimide (PMI) foam is presented and manufactured to meet the increasing demand of vibration suppression and load-bearing. The multiple bandgap generation mechanism and vibration suppression effect of the tubular multi-level resonator (TMR) are revealed by experimental and numerical methods. A strategy for composite lay-up orientation modulation (exploiting the severe anisotropy of CFRP, i.e. carbon fiber reinforced polymer, to achieve gradient variation of resonator stiffness) was proposed. This strategy is combined with the leg angle in resonator to realize a wide bandgap adjustment (approximately 170 Hz to 3000 Hz). In addition, the mechanical enhancement effect due to PMI foam filling is analyzed by the compression experiment. It can be observed from the results that lateral supports of PMI foam have respectively increased the structural compression strength and SEA by 33.7% and 61.5%.