The Design of Linear Magnetic Negative Stiffness Element for Engineering Application using Rectangular Permanent Magnets

Abstract

Negative stiffness element (NSE) has extensive uses in engineering applications, such as vibration isolation, energy harvesting, and mechanical metamaterial. However, to realize a linear negative stiffness characteristic is still a challenging task. In this paper, we present a compact magnetic negative stiffness element (MNSE) that composed of three rectangular permanent magnets and configured as repelling configuration in horizontal to realize linear negative stiffness characteristic. The effects of the MNSE configuration parameters on the negative stiffness characteristic are analyzed in detail. The results demonstrate that the magnitude of the negative stiffness characteristic can be adjusted by changing the height ratio and width ratio between the central and outer magnets. The height difference between the central and outer magnets can be used to tune the degree of nonlinearity of the negative stiffness characteristic and to get the uniformity stiffness characteristic in the equilibrium position. The procedure to realize the linear negative stiffness characteristic with the expected magnitude and displacement range is developed and confirmed. The proposed MNSE and the design procedure offer an engineering application foundation for the magnetic linear negative stiffness.