Non-Linear Simulation Model for Articulated Vehicles with Controllable Dampers and Flexible Sub-Structures

In this paper, a non-linear simulation analysis for a 4 axles tractor semitrailer vehicle is addressed using a 14 degrees-of-freedom ride model that includes the structural dynamics of both tractor and semitrailer frames. The system non-linearity is arising due to the inclusion of switchable dampers in the vehicle cab suspension systems. The modal properties of the articulated vehicle frames are calculated using the FEM (finite element method) and then incorporated with the rigid parameters and motions of the different components of the vehicle system. The equations of motion are derived taking into account the interaction between both tractor and semitrailer frames. The Runge-Kutta method has been used to solve the non-linear differential equations of motion of the vehicle system in the time domain. Random signals are used to simulate the road surface irregularities and to excite the components of the vehicle system with low and high roughness levels (smooth and rough roads). The effect of controllable dampers including two-state switching systems on the ride performance are investigated and compared to a passive system. During the modeling and assessment stages, reasonable damping constrains as well as vehicle loading and velocity conditions are taken into consideration. The results showed that suspension systems equipped with controllable dampers could reduce the vibrations levels of the vehicle cab and then improve the ride quality, which affect the driver and vehicle safety, within the scope of the factors considered in this study.