FAQ A06 - Powertrain: How to set the value of damping parameters when this value is requested by a submodel?

Category: Simcenter Amesim

Topic: Applicative solutions

Access Level: End User

Publish Date: November 2013

Question

Powertrain: How to set the value of damping parameters when this value is requested by a submodel?

Answer

You can find a simple example of setting damping parameters from the demo $AME/demo/Libraries/TR/LehrsDampingRatio:

The damping coefficient rtor is computed using the Lehr’s equation:

with:

rtor: damping coefficient [Nm/(rad/s)]

Z: damping ratio [-]

K: Stiffness [Nm/rad]

M: Mass (for translation) or Inertia (for rotation) [kg.m2]

This equation is using SI unit, in fact, we define in the model:

You can estimate damping coefficient from parameters as masses (or inertias ) and making an assumption the value of the damping ratio. This damping ratio is to set in order to get a satisfying behavior of the system. Usually, for an oscillating system, this behavior is considered as satisfying with a damping ratio between 0.01 and 0.1.