The benefits of nonlinear cubic viscous damping on the force transmissibility of a Duffing-type vibration isolator

Vibration isolation systems with nonlinear stiffness under sinusoidal excitation exhibit unwanted jump phenomena and superharmonics when they are lightly damped. These characteristics can be suppressed by linear viscous damping but the force transmissibility over the high frequency range increases as a result. In this study, nonlinear viscous damping will be chosen to solve this problem with the aid of a single-degree-of-freedom model with cubic stiffness. Simulation results show that nonlinear viscous damping can reduce the resonant peak as well as suppressing the adverse properties of nonlinear stiffness, jumps and harmonics, without compromising the transmissibility over the high frequency range. Nonlinear damping preserves the benefits of linear damping while removing the undesirable effects over the non-resonant regions and therefore improves the overall performance.