Dynamic model and vibration of rack vehicle on curve line

When rack vehicles traverse curved track sections, severe dynamic interactions between the gears and the rack, as well as between the wheel and rail, may lead to gear-rack disengagement or derailment, posing a safety risk. To address this, a coupled dynamics model of rack vehicles and track on curved sections is developed, based on gear system dynamics and vehicle-track coupling theory. The model is validated and used to investigate dynamic responses of rack vehicles on curved tracks, with a focus on gear-rack engagement dynamics. The study also examines how different curve radii influence vibration patterns. Results show that vehicle vibrations and dynamic meshing behavior are more severe on curved sections compared to straight ones. Specifically, the lateral acceleration of the vehicle body and the lateral force between the wheel and rail increase by 32.3% and 40%, respectively. During curve negotiation, lateral vibrations dominate over vertical ones, with gear offset reaching 1.323 mm. The primary frequencies of vehicle body acceleration and lateral force range from 1 to 3 Hz, while the frequencies for vertical and longitudinal gear acceleration vibrations range from 29 to 60 Hz. Additionally, vehicle body acceleration, derailment coefficient, and gear-rack meshing vibrations increase as the curve radius decreases.