Creating post-processing variables

We will now use the post-processing integrated features to compute the velocity and acceleration from the displacement of the body (body displacement variable).

Step 1: Create the post-processing variable for the velocity

Procedure

1. In Simulation mode, launch a simulation run.

2. Select the Body mass component so that its variables are displayed in the Contextual variables view window.

3. Open the Post processing tab if it is not already present (Edit > Show/Hide > Post processing).

4. Drag and drop the body displacement variable from the Contextual variables view window to the Post processing tab.

5. Edit the title to read computed velocity.

6. Edit the expression to read differ(x1@Body_Mass).

Step 2: Create the post-processing variable for the acceleration

Procedure

1. In the Post processing tab, right-click and select Add from the contextual menu.

A new line appears in the tab.

2. Edit the title to read computed acceleration.

3. Edit the expression to read differ(A1).

Step 3: Plot the results

If we plot the post-processing variable computed velocity and computed acceleration and compare them with body velocity and acceleration at port 1 we get similar results:

Figure 76: computed velocity and body velocity

Figure 77: computed acceleration and acceleration at port 1

Note

There are very small differences because computed velocity and computed acceleration are computed using the Simcenter Amesim expression interpreter whereas body velocity and acceleration at port 1 are computed by the Simcenter Amesim solver.