High-Speed Train-Track-Bridge Dynamic Interaction considering Wheel-Rail Contact Nonlinearity due to Wheel Hollow Wear

Table 1

Degrees of freedom of the vehicle.

Component	Type of motion
	Longitudinal	Lateral	Vertical	Roll	Pitch	Yaw
Car body	Xc	Yc	Zc	ϕc	βc	Ψc
Bogie frame (i = 1∼2)	Xti	Yti	Zti	ϕti	βti	Ψti
Axle box (i = 1∼8)	—	—	—	—	βai	—
Wheel set (i = 1∼4)	Xwi	Ywi	Zwi	ϕwi	βwi	Ψwi