Research on Nonlinear Dynamic Characteristics of Semi-active Suspension System with SMA Spring

In this paper, the nonlinear dynamic characteristics of vehicle semi-active suspension system with SMA spring was studied. SMA spring was applied in semi-active suspension system to substitute ER and MR fluid to provide controllable force. Hysteretic cycle and multinomial model were introduced to set up a new kind of continuous SMA strain-stress-temperature model, based on which the nonlinear dynamic model of vehicle semi-active suspension system with SMA spring was set up. The first-order nonlinear approximate solution of suspension system was given, and based on which the stability and bifurcation characteristic of suspension system were analyzed. The result of analysis shows that the nonlinear stiffness parameters can not cause the bifurcation of suspension system, and the qualitative change of the dynamic characteristic of suspension system has relationship with the nonlinear damping parameters. Finally, the result of analysis was proved by simulation.