Dynamic runs and stabilizing runs

run dynamic

run stabilizing

Sometimes we have a very big system and a dynamic run takes a long time. Ideally we would like to start the simulation with the system in an equilibrium state but do not want to wait for a long dynamic run to finish.

Procedure

1. Select the Step submodel and set the Value after step to 1.

2. In Simulation mode, click on the Run parameters button .

The Run parameters dialog box appears.

3. Set the Print interval to 0.002 s.

4. Click on the Standard options tab.

5. Look at the Simulation mode area.

By default the Dynamic mode is selected and Stabilizing mode is not. You can select one or both of these modes.

6. Click on the Stabilizing radio button.

7. Do a run and examine the results for the Body_Mass.

Figure 44: Variables of the mass

You will find that the velocity and acceleration have negligible values and the body is in its equilibrium position. The car body has dropped a distance of:

Here, Distance = Mbody * g / Ksuspension + (Mbody + Mwheel) * G / Ktyre

Note

It is not possible to produce a meaningful plot because there is not enough data.

There is a confusing collection of terms which mean (almost) the same thing:

• stabilizing run

• steady-state run

• free response run

• equilibrium position run

Stabilizing run is the Simcenter Amesim Run preferred term. At this stage it is useful to define more precisely what we mean by a state variable.