Table 1 List of parameters.

From: Nonlinear dynamics of a non-stationary rotor-disk-bearing system with rub-impact and geometric nonlinearity under non-ideal excitation

Parameters

Definition

Parameters

Definition

\(M_{\text {ud1}}\)

Unbalance mass of disk 1

\(M_{\text {d2}}\)

Mass of disk 2

\(M_{\text {ud2}}\)

Unbalance mass of disk 2

v(xt)

Displacement in the z-axis

I

Moment of inertia of shaft

w(xt)

Displacement in the y-axis

\(I_{21}\)

Diametrical mass moment of inertia of disk 1

\(K_h\)

Radial stiffnesses of the stator

\(I_{22}\)

Diametrical mass moment of inertia of disk 2

\(K_l\)

Linear stiffnesses of the bearings

\(I_{11}\)

Polar mass moment of inertia of disk 1

\(K_{nl}\)

Nonlinear stiffnesses of the bearings

\(I_{12}\)

Polar mass moment of inertia of disk 2

\(C_b\)

Damping of the bearings

\(\dot{\beta }\)

Shaft rotational speed

\(C_r\)

Damping of the shaft

\(r_1\)

Eccentricity of the disk 1 unbalance

\(\rho\)

Mass density of shaft

\(r_2\)

Eccentricity of the disk 2 unbalance

A

Shaft cross-sectional area

\(M_{\text {d1}}\)

Mass of disk 1

E

Young’s modulus of elasticity of the shaft