Spline Stiffness Model

The spline stiffness formulation interpolates a Force vs. Deflection table using Akima’s cubic interpolation method. For values of deflection outside the supplied range, the force is linearly extrapolated using the slope at the corresponding end-point. For each direction employing the spline-stiffness formulation, you must supply a Force vs. Deflection table in the property file. The force is calculated as follows:

Where:

$q_i$ is the displacement of Body-I relative to Body-J in the $i^{th}$ direction after offset, scaling and coupling effects have been considered.

$table$ is the force-deflection table specified in the [SPLINE_STIFFNESS_xx] block in the .gbs file.