Theoretical study of the effects of nonlinear viscous damping on vibration isolation of sdof systems

The present study is concerned with the theoretical analysis of the effects of nonlinear viscous damping on vibration isolation of single degree of freedom (sdof) systems. The concept of the output frequency response function (OFRF) recently proposed by the authors is applied to study how the transmissibility of a sdof vibration isolator depends on the parameter of a cubic viscous damping characteristic. The theoretical analysis reveals that the cubic nonlinear viscous damping can produce an ideal vibration isolation such that only the resonant region is modified by the damping and the non-resonant regions remain unaffected, regardless of the levels of damping applied to the system. Simulation study results demonstrate the validity and engineering significance of the analysis. This research work has significant implications for the analysis and design of viscously damped vibration isolators for a wide range of practical applications. © 2009 Elsevier Ltd. All rights reserved.