Ride analysis of railway vehicle considering rigidity and flexibility of the carbody

ABSTRACT In this paper, a twenty-one degrees of freedom mathematical model of a railway vehicle is formulated, considering its main components (i.e. carbody, bolster, bogie frame, and wheel axle) as rigid for the rigid body analysis of ride behavior of the vehicle. The ride comfort of the vehicle is analyzed and optimized using ISO 2631 criteria. Further, vertical flexibility of the carbody is accounted for with few modifications in the model, and the effect of vertical stiffness on ride behavior is analyzed and compared with a rigid carbody analysis using the Spering ride index. The carbody bending frequencies are investigated using the covariance method, and it is found that the reduction in stiffness of carbody beyond a specific frequency introduces significant carbody acceleration and declines the vehicle ride. The increased carbody bending frequencies can achieve higher vehicle speed and adequate isolation from track excitations.