A novel bi-material negative stiffness metamaterial in sleeve-type via combining rigidity with softness

Negative stiffness metamaterials (NSM) can dissipate mechanical energy repeatedly based on a snap-though mechanism. However, this mechanism is only effective when many NSM cells are arranged in series or such cell is assembled with a spring. Limits of the mechanism bring a challenge to improve the energy dissipation capacity of the NSM. Here, a novel bi-material NSM in sleeve-type (BMST-NSM) is designed which can dissipate mechanical energy even if the metamaterial is only composed of one negative stiffness cell. The quasi-static loading?unloading experiment is conducted to investigate the characteristics of BMST-NSMs; a multilinear model is presented to characterize the load?displacement curve of BMST-NSMs; and the finite element method (FEM) is used to study the characteristic of strain distribution in BMST-NSMs. Research results show that BMST-NSM can be tailored to be recoverable or multi-stable through parameter design. BMST-NSMs are also tested under different loading speeds and high cyclic loading, which shows that the recoverable BMST-NSM is of good reusability and energy dissipation ability. Moreover, it indicates that BMST-NSM can exhibit a high energy absorption capability within a certain limited displacement range. The presented BMST-NSM has great prospects in low ultra-low frequency vibration isolation and energy dissipation in impacting protection.

Automated summary

Negative stiffness metamaterials (NSM) have the capability to repeatedly dissipate mechanical energy, but typically require multiple cells arranged in series or assembled with a spring. A novel bi-material NSM in sleeve-type (BMST-NSM) is introduced, which can dissipate energy even with just one negative stiffness cell, and can be tailored to exhibit recoverable or multi-stable behavior through parameter design. Through testing, it has been demonstrated that BMST-NSM shows good reusability, energy dissipation ability, and high energy absorption capability within a limited displacement range, making it promising for low ultra-low frequency vibration isolation and impacting protection applications.