Design and performance validation of a zero-stiffness vibroisolating metamaterialbased on machine learning

The quasi-zero stiffness isolator, as a mainstream nonlinear isolator both domestically and internationally, was widely applied in the field of mechanical engineering due to its high static stiffness and low dynamic stiffness mechanical characteristics. However, limitations such as a narrow range of quasi-zero stiffness, complicated post-assembly procedures, etc., had restricted its application scope in vibration isolation. Through structural design, the range of quasi-zero stiffness could be expanded, and research on rapid preparation through integrated molding technology was still relatively scarce. In that study, a novel zero stiffness unit structure was designed based on the theory of energy shielding. By circulating external input energy within the metamaterial, the energy input from the external environment to the isolated object was shielded, thus achieving the isolation effect. The research first designed an initial structure with optimization potential, then used a combination of machine learning and finite element analysis to optimize the initial structure, automatically searching for the optimal parameters of the metamaterial structure. The optimal structure met the requirements of zero stiffness performance design. Subsequently, 3D printing was employed to manufacture the optimal structural unit and a 2×2 array structure in an integrated manner. Static experiments were conducted on the samples for validation. The experimental results show that the equivalent stiffness of this structure approximates zero over a wide range during static compression. Dynamic vibration experiments were also conducted on the array structure. The results reveal that within the range of 0.1 Hz to 100 Hz and under a 23 mm amplitude, the array structure exhibites its best isolation performance with a 9.2 kg load, achieving a minimum transmissibility of up to −61 dB. The closer the load is to 9.2 kg, the better the isolation performance. This structure offers advantages such as simplicity in design, integrated molding, etc., and can be applied in vibration isolation for fields such as train seats, rehabilitation medical equipment, protection of precision instruments, and microgravity environments.