4.6.2. Modeling Tips

Copy & Paste the Spline in Spline List

The user can copy and paste a spline in Spline List. This function is possible in the same model only.

• When the user copies the spline, the user clicks the right mouse button after the mouse cursor putting on the spline.

  

  Figure 4.29 Spline List dialog box

Example to use z value in spline

Spline not only returns y value according to x value, but it can also define a lookup table that outputs y values as a function of x and z values.

Let us consider an example in which the x and z values are set from 0 to 30, and the y value increases according to the x and z value increase.

Figure 4.30 3-axis data table

To create this 3D table example in RecurDyn, user needs to add the Z value. It can be added by pressing the Append Z Value button in Spline dialog, and the number of Y columns increases as the row value of Z increases. That is, the Z value is included for each Y curve. In Figure 4.31, there is an example of creating the table of the previous example.

Figure 4.31 Example of creating 3D table in Spline dialog

If there are 4 rows of Z value, there are 4 Y columns (Y1, Y2, Y3, Y4). It means there are 4 spline curves.

Figure 4.32 Spline Viewer dialog for 3D table example

Then, 2 spline curves are used to return the linearly interpolated value from them. For example, if x=5 and z=25 (AKISPL(5,25,spline_curve)),

since 20<25<30,

Y1 = AKISPL(5,20,spline_curve) = 11.18

Y2 = AKISPL(5,30,spline_curve) = 13.13

As a result, AKISPL(5,25,spline_curve) = 12.155

Figure 4.33 Linear interpolation for Z value

Direct open Spline dialog in Database

The user can open the Spline dialog directly from the database without going through the Spline List dialog.

• The user can open the spline dialog using the right mouse menu Properties.

• The user can open the spline dialog using the shortcut P.

• The user can open the spline dialog with mouse double clicking.