A compressible square-frustum sandwich structure for low-frequency vibration suppression: Numerical and experimental analyses

Designing a lightweight structure with good load-bearing for low-frequency vibration suppression is a challenge. This study develops a new sandwich structure with a double hollow square frustums core (DHSFCSS) that exhibits excellent out-of-plane compressive and low-frequency vibration suppression performances. Uniaxial compression tests are conducted to study the out-of-plane compressive performance of the three-dimensional (3D)-printed DHSFCSS. The band structure of the DHSFCSS is numerically calculated and validated by the frequency response and the vibration tests. The effects of geometric parameters on the out-of-plane compressive and vibration suppression performances of the DHSFCSS are studied. The results show that the maximum load-mass ratio is over 263 N/g and the maximum SEA reaches 2936.6 kJ/kg. Those are markedly improved over some previous studies. There are two bandgaps below 1500 Hz. The DHSFCSS is suitable for low-frequency vibration suppression. A gradient DHSFCSS is proposed to obtain bandgaps with wider and lower frequency ranges. Nonreciprocal transmission and rainbow trapping effects can be realized by the gradient DHSFCSS. These show gradient structural potential applications in energy harvesting and elastic wave manipulation.