Spline Check and Repair

The Spline Check and Repair tool allows you to check the quality of the splines that are used to define the stiffness and damping of the following components:

Several spline defects can be detected and repaired automatically. The tool checks for these common errors, and repairs them if desired. The check and repair operations may be performed on a single spline, an entity type (for example, ac_bushing), a subsystem, an assembly, or an entire database. The user can choose to perform any one or more of the following checks:

When this check is performed, the spline(s) will be examined for symmetry about the specified origin, where the default is (0, 0). If asymmetry is detected and the repair option is selected, the quadrant with the greater number of values will be mirrored to the quadrant having the smaller number.

This checks whether the curve passes through the origin (0, 0). This is useful, for example, because a spring or damping curve that does not pass through (0, 0) has the effect of a preload force. If the curve fails this check and the repair option is selected, then a (0, 0) point is added, unless there is a (0, Y) data point, in which case the Y value is set to 0.

This checks whether the curve's abscissa is evenly spaced. This may be important because the Akima spline interpolation (AKISPL) works best on evenly spaced data. If the curve fails this check and the repair option is selected, then the curve will be resampled. The new sampling rate is determined using either the smallest interval of the existing data points or by the specified number of points.

This checks whether a minimum slope value is maintained. One can hereby detect constant values of the Y-axis. If the curve fails this check and the repair option is selected, then the user will be warned and prompted to manually modify the spline manually. If the Minimum Slope check is selected, the following monotony checks are not available, since they are guaranteed to pass if the spline meets the minimum slope criterion.

This check is intended to ensure a monotonically consistent (always increasing or decreasing) curve. This is useful, for example, because a damping curve with an inconsistent slope may lead to a self-exciting system. If the curve fails this check and the repair option is selected, then the user is warned and prompted to repair this manually.

This check is performed on the spline derivative. It is intended to ensure a monotonically consistent (always increasing or decreasing) slope. If the curve fails this check and the repair option is selected, then a user-specified filter will be applied to the spline in attempt to smooth the data.