SPLINE4

Bulk Data Entry Defines a curved surface spline for interpolating motion and forces for aeroelastic problems on aerodynamic geometries.

Format

(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)
SPLINE4 EID CAERO AELIST SETG DZ METH USAGE

Example

(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)
SPLINE4 56 33 12 11 0.0

Definitions

Field Contents SI Unit Example
EID Unique spline identification number.

(Integer > 0)

CAERO Identification number of the aerodynamic component that defines the interpolation surface.

(Integer > 0)

AELIST Identification number of an AELIST entry listing the boxes to be interpolated using this spline.

(Integer > 0)

SETG Refers to the SET1 entry that lists the structural grid points to which the spline is attached.

(Integer > 0)

DZ Linear attachment flexibility. 1.

Default = 0.0 (Real ≥ 0.0)

METH Spline fit method.
IPS (Default)
Harder-Desmarais Infinite Plate Spline.
TPS
Thin Plate Spline.
USAGE Spline usage flag. 2
BOTH (Default)
For both force and displacement transformations.

Comments

  1. The attachment flexibility (units of area) is used for smoothing the interpolation. If DZ = 0.0, the spline will pass through all deflected grid points. If DZ is much greater than the spline area, a least squares plane fit will be applied. Intermediate values will provide smoothing.
  2. The USAGE field allows you to specify that the particular spline interpolant defined in this entry is to be used for both the force transformation and the displacement transformation. Currently, only the BOTH option is supported for the USAGE field.
  3. SPLINE4 cannot be used for slender bodies (CAERO2).