Advances in vibration isolation by locally resonant mechanical metastructures with nonlinear stiffness

With the growing complexity of engineering systems, the demand for effective vibration isolation, particularly in low-frequency and specific frequency bands under high loads, continues to rise. Traditional isolation techniques often fail to meet these requirements due to their limited performance in such conditions. In response, researchers have explored innovative approaches involving nonlinear stiffness design and mechanical metastructures with bandgap regulation. Nonlinear stiffness is achieved through mechanisms such as negative stiffness elements, gradient beams, and biomimetic hinges, enabling “high-static-low-dynamic” behavior to reconcile static load support with dynamic isolation. Meanwhile, mechanical metastructures utilizes subwavelength local resonance to generate bandgaps, overcoming size constraints in low-frequency isolation. By integrating photonic crystal theory and Bloch wave analysis, the underlying mechanisms of bandgap formation are revealed, and nonlinear designs are employed to broaden isolation bandwidths. The advances systematically review the design strategies of locally resonant metastructures incorporating nonlinear stiffness, and highlights recent advances in broadband, low-frequency isolation. The findings provide theoretical guidance and technical references for both academic studies and practical applications in vibration isolation using locally resonant mechanical metastructures.