Rotary friction

| C |
in the palette on the schematic

The block is designed to simulate the contact friction of two rotating surfaces with a constant pressing force.

The relative slip speed ω in rad/s is determined by the formula:

where ωC, ωR – angular speeds at ports "C" and "R", respectively, rad/s

The Stribeck curve [1] and viscous friction (Figure 1) are used to determine the friction torque.


Figure 1. Dependence of friction torque on relative speed
The friction torque is determined by the formula:



where:
  • TC and TC – torques applied to ports "C" and "R", respectively, Nm
  • Tbrk – breakaway friction torque, Nm
  • Tc – dry (coulomb) friction torque, Nm
  • ωth – breakaway angular speed, rad/s
  • C – damp ratio, s/rad
  • Fr – coefficient of internal friction, Nm·s/rad

The value of the breakaway friction torque Tbrk in Nm is displayed next to the block.

Inputs

Name Description Connection line type
C Port for connecting a conditionally fixed case (case) Rotary mechanics
R Port for connecting a conditionally moving shaft (rotor) Rotary mechanics

Outputs

None.

Properties

Name Parameter Description By default Data type
Breakaway friction torque, Nm Tbrk Breakaway friction torque 2 Вещественное
Breakaway angular speed, rad/s Wth The threshold value of the speed below which the value of the friction torque is reduced to achieve the stability of the numerical solution 0.001 Вещественное
Dry (coulomb) friction torque, Nm Tc Dry (coulomb) friction torque 1 Вещественное
Damp ratio, s/rad C Damp ratio 1 Вещественное
Coefficient of internal friction, Nm·s/rad Fr Coefficient of internal friction 0.1 Вещественное

Parameters

Name Parameter Description Data type
Angular speed differential, rad/s W Relative slip speed Вещественное
Friction torque, Nm T Torque at the port "R" Вещественное
Power of friction torque, W Q Power of friction torque, W Вещественное

Examples

Examples of block application:

Literature

  1. Richard Stribeck: Die wesentlichen Eigenschaften der Gleit- und Rollenlager, Z. Verein. Deut. Ing. Vol. 46 Seite 38ff. 1341–1348 (1902).