In the analysis and design of vehicle suspension systems, springs and dampers, which are usually inherently nonlinear, are the most crucial elements to improve the ride comfort, assure the stability, and increase the longevity of suspension systems to a large extent. Therefore, it is of great significance to determine a proper stiffness and damping characteristics to meet various requirements in practice. In this study, a nonlinear frequency domain analysis method is introduced for nonlinear analysis and design of vehicle suspension systems. The explicit relationship between system output spectrum and model parameters is derived by using the nonlinear frequency domain analysis method, and the characteristic parameters of interest can therefore be analyzed directly. The optimal nonlinear stiffness and damping characteristics of vehicle suspension systems can then be achieved. Comparative studies indicate that the optimal nonlinear damping characteristics demonstrate better dynamic performance than the corresponding linear counterparts and several existing nonlinear optimal damping characteristics obtained by simulations. Simulation studies based on the full vehicle dynamic model verify the nonlinear advantages in terms of three different vehicle evaluation standards. The study shows that the nonlinear optimal damping characteristic obtained by using the nonlinear frequency domain analysis method is very helpful in improvement of vehicle vibration performance and decrease of suspension stroke. Meanwhile, the optimized nonlinear damper will not cause any negative effect on the handling capability.

Chapter Contents:

• Abstract
• 13.1 Introduction
• 13.2 System model and the output frequency response function (OFRF) method
• 13.2.1 System model
• 13.2.2 Determination of the system OFRF
• 13.2.3 Optimization and system analysis
• 13.2.4 Conclusion
• 13.3 Comparative studies
• 13.3.1 Existing nonlinear damping characteristics
• 13.3.2 Damping characteristics designed via the OFRF-based analysis method
• 13.3.3 Comparative studies
• 13.3.4 Dynamic model verification
• 13.3.5 Conclusion
• 13.4 Application on a dynamic vehicle model
• 13.4.1 Dynamic vehicle model
• 13.4.2 Simulation study
• 13.4.3 Summary
• 13.5 Conclusion and future work
• References

Inspec keywords: vibrations; springs (mechanical); frequency-domain analysis; shock absorbers; vehicle dynamics; elastic constants; mechanical stability

Other keywords: ride comfort improvement; full vehicle dynamic model; proper stiffness determination; vehicle vibration performance improvement; nonlinear optimal damping characteristic; model parameters; nonlinear frequency domain analysis method; decrease suspension stroke; system output spectrum; springs; nonlinear vehicle suspension systems; stability assurance; vehicle evaluation standards; dampers; optimal nonlinear stiffness; frequency domain design

Subjects: Elasticity (mechanical engineering); Vibrations and shock waves (mechanical engineering); Buckling and instability (mechanical engineering); Mechanical components; Mathematical analysis; Vehicle mechanics