Design and performance validation of a magnetic-pneumatic high-static-low-dynamic stiffness isolator

In previous studies, design methods for high-static-low-dynamic stiffness (HSLDS) isolators have mostly focused on unidirectional vibration isolation under specific loads, making them unable to meet the isolation requirements of ship piping and electromechanical equipment under variable loads and multi-dimensional vibration conditions. This study proposes a high-static-low-dynamic stiffness design method with an adjustable equilibrium position and three-dimensional vibration isolation capabilities, which effectively reduces three-dimensional natural frequencies and improves low-frequency vibration suppression under different loading conditions. In the vertical direction, without sacrificing load capacity, the natural frequency is reduced by connecting magnetic arrays and air springs in parallel. In the radial direction, a design method is proposed in which the radial supporting force of the air spring is counteracted by the eccentric magnetic force generated by the offset of the magnets, thereby reducing three-dimensional natural frequencies and improving vibration isolation performance. Subsequently, based on this method, a three-dimensional magnetic-pneumatic HSLDS isolator is designed. Experiments show reduced vertical and radial natural frequencies under variable-load conditions. Broadband vibration tests further confirm improved vertical isolation and enhanced attenuation of the measured radial vibration component under the present excitation configuration. This study presents a solution for the three-dimensional vibration reduction in ship piping and electromechanical equipment.