Damping control in a spring and suspension with sign-changing stiffness

Vibration isolation in a range as close to zero frequency as possible is important for human and sensitive high-precision equipment. Springs with variable sign-changing stiffness can cancel the stiffness and provide perfect vibration isolation. However, it is possible in certain damping conditions. This paper presents an approach of damping control in suspensions with such springs. A model of the mode of deformation is formulated and validated for analysis of structural damping in the springs. A vibration model is formulated to estimate a maximum efficiency of a soft suspension in the infra frequency range and predict a reasonable level of slip damping. Novel materials and designs are demonstrated for control and minimization of the damping. Validity of the approach is illustrated with numeric and measured data obtained from development test of the springs and suspensions equipped with such springs.