Dynamic characteristics of a piecewise damping passive vibration isolator based on translating cam mechanism

This study proposes a passive vibration isolator with a piecewise damping characteristic based on a translating cam mechanism to address the trade-off between resonance suppression and high-frequency isolation in conventional linear systems. The proposed design enables zero damping at small displacements and activates damping beyond a prescribed threshold through the geometric segmentation of the cam profile. A nonlinear dynamic model of the system is established, and an equivalent damping formulation is derived based on cam kinematics. The dimensionless governing equations are obtained, and the amplitude–frequency response is analyzed using the method of averaging. Numerical simulations based on the fourth-order Runge–Kutta method are conducted for validation. The results show that the proposed isolator effectively reduces the resonance peak while maintaining low transmissibility in the high-frequency region. Compared to conventional linear damping systems, the optimized design achieves a reduction of 37.8% in resonance amplitude and a decrease of 15.3% in average high-frequency transmissibility. The analytical predictions are in good agreement with numerical results. These findings demonstrate that the proposed cam-based piecewise damping mechanism provides an effective purely mechanical solution for improving vibration isolation performance.