Reaction Rod Link in Rear Cab Suspension to Control Cab Dynamics in Tractor-Semitrailer Vehicles

Articulated vehicles form an important part of our society for the transport of goods. Compared to rigid trucks, tractor-trailer combinations can transport huge quantities of load without increasing the axle load. The fifth wheel (FW) acts as a bridge between the tractor and trailer, which can be moved within the range to achieve rated front and rear axle loads. When the FW is moved front, it adversely affects the cab dynamics and cab suspension forces. Compared to the cab pitch and roll, yaw motion increases drastically. The current study tries to address this issue by providing reaction rod links in the rear cab suspension. In this study, a 4×2 tractor with a three-axle semitrailer is considered by keeping the FW at its frontmost position, which is the worst-case scenario for a cab. Three different cases of reaction rod arrangement and its influence on cab dynamics are studied in comparison with a model without reaction rods. To assess this, time signal–based relative pseudo-fatigue damage, power spectral density (PSD), and level crossing plots are analyzed. The outcome shows that cab pitch, roll, and yaw motion reduce by a considerable amount with the presence of a reaction rod. Cab suspension forces will also reduce. The horizontal V-inclination of the reaction rod plays a major role in improving cab yaw motion and reducing the lateral forces. A straight link without any inclination helps in reducing the pitch and roll motion of the cab.