Ride comfort analysis of a railway vehicle moving on straight track and subjected to average vertical profile (AVP) excitation

In this paper numerical simulation of the ride dynamic behavior of a coupled railway vehicle and track system is presented. A typical Indian railway vehicle of the Alternating Current/Electrical Multiple Unit/Trailer (AC/EMU/T) type running on broad gauge track has been used for the analysis. In numerical implementation, the coupled vehicle and track system is divided into two parts, vehicle and track. The vehicle in the coupled system is a rolling stock and is modeled as a rigid body with 10 Degrees Of Freedom (DOF). The lower structure in the coupled system is a railway track where rails are considered as beams with finite length resting on a continuous elastic foundation. Coupling between the vehicle system and railway track is realized through interaction forces between the wheels and the rail. Linear governing equations of motion of the vehicle have been solved and natural frequencies determined. Dynamic response studies were carried out in the time and frequency domains for the vehicle moving on a straight track with the irregularity of the track vertical profile given as input. The excitation forces due to these inputs were introduced through Hertzian springs connected to the vehicle/track interface. The ride dynamic performance of the vehicle has been evaluated in terms of Sperling's ride indices for both ride comfort and ride quality at different speeds.