In-plane quasi-zero-stiffness vibration isolator using magnetic interaction and cables: Theoretical and experimental study

Quasi-zero-stiffness (QZS) vibration isolators can achieve much wider isolation region than equivalent linear isolators. However, most of the existing QZS isolators are designed for a specified direction especially the vertical direction. To broaden the application scope of QZS isolators, this paper presents an in-plane QZS isolator to isolate the vibration occurring in arbitrary direction in the horizontal plane. The proposed isolator is composed of two magnetic rings that are radially magnetized and eight cables that are pre-tensioned. The magnetic interaction offers negative stiffness and the combination of cables offers positive stiffness, which therefore allows the realization of QZS characteristic by proper parameter selection. The vibration in horizontal arbitrary direction can be decomposed into two vibrations in two specified orthogonal directions. Theoretical analysis shows that the proposed isolator possesses superior vibration isolation performance in both the two directions, in terms of bandwidth of isolation region, peak transmissibility and high frequency transmissibility. The superior isolation performance is also demonstrated by experiments.