A nonlinear locally resonant metamaterial beam with customized stiffness for low-frequency and broadband band gaps

Nonlinear locally resonant metamaterial structures exhibit significant advantages in achieving band gaps with low-frequency and broadband characteristics. However, the limitations of nonlinear virtual models and the insufficient stiffness adjustment mechanism of actual physical models have led to a significant lack of flexibility in band gap design in practice. To address these limitations, this study introduces a hardening nonlinear stiffness customization strategy through an improved cam-roller structure for generating band gaps in nonlinear locally resonant metamaterial beams. The band gap adjustment mechanism and vibration mitigation of the metamaterial beam are examined. The findings reveal that by adjusting the stiffness parameters in the metamaterial beams based on this strategy, it is possible to flexibly generate the target band gaps with low-frequency and broadband characteristics. In addition, the effective attenuation range and effect of the structure are influenced by the excitation amplitude and the layout of the local oscillator. Finally, the feasibility of achieving the nonlinear band gap is verified through experimental methods. • A stiffness customization strategy is proposed to generate band gap with low-frequency and broadband characteristics. • The uncoupled design of linear stiffness and nonlinear stiffness can flexibly generate different band gaps. • Experimental research has confirmed the theoretical band gap caused by hardening nonlinearity.