Numerical Investigation into the Critical Speed and Frequency of the Hunting Motion in Railway Vehicle System

Table 2

Notation	Parameter	Value	Unit
	Car body mass	28000	kg
	Bogie frame mass	3000	kg
	Wheelset mass	2400	kg
	Roll moment of inertia of car body	84560	kg·m^2
	Yaw moment of inertia of car body	1102730	kg·m^2
	Roll moment of inertia of bogie frame	2106	kg·m^2
	Yaw moment of inertia of bogie frame	2600	kg·m^2
	Yaw moment of inertia of wheelset	1029	kg·m^2
	Longitudinal stiffness of primary suspension	85	MN/m
	Lateral stiffness of primary suspension	15	MN/m
	Vertical stiffness of primary suspension	1.1	MN/m
	Longitudinal stiffness of secondary suspension	0.2	MN/m
	Lateral stiffness of secondary suspension	0.2	MN/m
	Vertical stiffness of second suspension	0.2	MN/m
	Lateral damping of primary suspension	10	kN·s/m
	Vertical damping of primary suspension	20	kN·s/m
	Lateral damping of secondary suspension	30	kN·s/m
	Vertical damping of secondary suspension	10	kN·s/m
	Series stiffness of yaw damper	10	MN/m
	First stage damping of yaw damper	300	kN·s/m
	Second stage damping of yaw damper	20	kN·s/m
	Blow-off force of yaw damper	3000	N
	Blow-off velocity of yaw damper	0.01	m/s
	Half of track gauge	0.7465	m
	Half of primary spring arm	1	m
	Half of secondary spring arm	1.23	m
	Half of secondary vertical damping arm	1.323	m
	Half of yaw damper arm	1.35	m
	Vertical distance from car body center of gravity to secondary suspension	0.852	m
	Vertical distance from car body center of gravity to secondary lateral damping	0.97	m
	Vertical distance from bogie frame center of gravity to secondary suspension	0.162	m
	Vertical distance from bogie frame center of gravity to wheelset center	0.148	m
	Vertical distance from bogie frame center of gravity to secondary lateral damping	0.044	m
	Longitudinal distance from bogie frame center to car body center	8.75	m
	Half of wheelbase	1.25	m
	Longitudinal creep force coefficient	8.4	MN
	Lateral creep force coefficient	8.4	MN
	Lateral/spin creep force coefficient	3000	N·m^2
	Spin creep force coefficient	16	N
	Axle load	10900	kg
	Normal force acting on wheelset	53410	N
	Coefficient of friction	0.3	—
	Acceleration of gravity	9.8	m/s^2