Design, analysis and experimental validation of high static and low dynamic stiffness mounts based on target force curves

Abstract

In order to improve vibration isolation, soft components can be used in engineering applications, but this can lead to excessive static deflection. An ideal vibration isolator should have a high static stiffness to ensure that it has sufficient load carrying capacity; at the same time, it should have a low dynamic stiffness to maximize the vibration isolation frequency range. Recently, high static and low dynamic stiffness (HSLDS) mounts have been increasingly shown to have significant benefits for various engineering applications. This paper proposes a method for designing HSLDS mounts based on target force curves. In the design method, the HSLDS mount is obtained by placing a negative stiffness structure in parallel with a positive stiffness linear spring. The negative stiffness structure is achieved by using a roller-slider curve which can be designed according to the requirements to achieve the target force curve. HSLDS mounts are proposed with nth-order stiffness behavior​ which are designed using the method presented here. The results show that, compared with lower order HSLDS mounts based on the same static stiffness, higher order HSLDS mounts have lower dynamic stiffness near the equilibrium position. The Average Method is used to analyze the dynamics of a system based on the nth-order HSLDS mounts, and the displacement transmissibility under harmonic excitation is obtained. The effects of different parameters on the transmissibility are studied. The results show that appropriately increasing the damping ratio is beneficial for the isolation performance of the HSLDS mount. Finally, an experimental prototype is designed and manufactured. The proposed design method and the vibration isolation performance of the HSLDS mount are verified by constant-frequency excitation experiments.