EFFECTS OF LOADING MASS ECCENTRICITIES ON UNSPRUNG MASS ROTATIONAL DYNAMIC RESPONSES OF HEAVY VEHICLE ON IRREGULAR ROAD PAVEMENT

Abstract

Using individual independent unsprung masses in suspension system modeling is not a realistic reflection of vehicle dynamics in response to eccentric wheel kinematics and asymmetric heavy vehicle loading. This is because the use of such masses does not accurately represent the unsprung mass system's influence on heavy vehicles' dynamics, including its impact on the sprung masses or wheel pavement dynamic loading. This study aims to examine how heavy vehicle asymmetric loading and wheels' eccentric kinematic excitation affect the rotational dynamic response of the unsprung masses. A total of 450 models were used to investigate various asymmetrical cases, from which 9 3D 24 DOF heavy vehicles' 4 DOF rear tandem drive axle suspension systems were selected for analysis using SIMWISE 4D. These vehicles were tested for a pothole depth of 25 mm and a vehicle translational speed of 60 km/h. The study found that the nature of the pavement distress factor (kinematic excitation) determines the suspension's rotational dynamic response and, consequently, the sprung mass. Moreover, the load distribution on the sprung mass also affects the rotational dynamic response of the tandem beams