Spring-damper

Rotational spring and damper between two shafts.

  • rotational
  • Gradara equations
  • 2 ports
  • 2 parameters
BlockSpring-damperKindspringDamperLibraryRotational

Description

A linear torsion spring and viscous damper in parallel between two shafts. Use it for a compliant coupling or a flexible shaft.

Example

Clutch, backlash, and rotational sources A clutch that locks, gear backlash, a spring-damper coupling, and a load that steps its torque.

100 rad/s at 0.1 sDriveClose at 0.5 sClutchDriven 1 kg·m²Driven speedω ref 10 sin 2πtSpeed sourceBacklash 0.1 radInertia 0.01Speed behind backlash0.5 N·mTorque sourceCouplingInertia 0.02, damping 0.05Coupled speed0.4 N·mShaft loadLoad speed
In Gradara, select a Spring-damper block and press F1, then choose Open example. It opens as a new model in My models, ready to run.

Also in this example:ConstantMechanical loadStepInertia & loadSpeed sensorSine waveBacklashInertia (ideal)ClutchTorque sourceConstant torqueSpeed sourceSpeed sensor (ideal)

Ports

Conserving terminals 2

  • arotational

    Flange a. Torque into the flange is positive.

  • brotational

    Flange b. Receives the opposite torque: b.tau = −a.tau.

Parameters

  • Stiffnessc10 N·m/rad

    ≥ 0

    Torsional stiffness, in N·m/rad. Zero or positive.

  • Dampingd0.1 N·m·s

    ≥ 0

    Damping coefficient, in N·m·s. Zero or positive.

Equations

Modelica
τ = c · (b.phi − a.phi) + d · (dφ_b/dt − dφ_a/dt)
b.tau = τ, a.tau = −τ

Assumptions and limitations

  • The spring is unstretched when both flanges are at the same angle; there is no offset parameter.

Tips

  • For an unstretched angle other than zero, use Torsion spring and Torsion damper in parallel.

See also

Select a block in Gradara and press F1 to open its page offline.