The Investigations of Suspension Model and Its Experimental Characteristics for the Air Springs of Truck Trailer

Air springs applied as shock damping elements are often found in the design of variety modern truck and trailer suspensions. They can also be found as damping and stabilizing suspension elements in the passenger cars and other machines. The advantage of air springs, compared to steel coil springs or leaf springs, is a better damping quality in a wide range of frequencies. The air springs stiffness can be regulated according to the requirements and working conditions. The applied air springs also allow to stabilize the distance between the vehicle body and road level in function of loading. Some proposals of vehicle suspension models can be found in technical literature where the air spring is the main elastic subassembly. Mathematical model descriptions of the suspension with air spring for vehicles apply the thermodynamic laws and relationships between the mechanical forces of cooperating suspension elements, parts geometry (suspension arms), material stiffness (reinforced rubber) and other properties (damping). The results of own investigations on the suspension model of an air spring for cargo trailer have been taken into consideration in this paper. The presented suspension model was applied to design the frame construction of a light stanchion trailer where aerodynamic drag and construction mass were reduced. The suspension model of air springs for a trailer was applied for frame loads evaluation of the light trailer. It was also used for the strength analysis of the frame construction with the reduced mass. The estimated frame loads such as torque, normal forces and bending moments were used for strength estimation of the upgraded trailer frame.