M. To assign multilinear springs to spring supports
To model varying resistance to external loads at a spring support, use the following procedure.
You must assign spring supports to nodes before assigning multilinear spring definitions. You may not use multilinear springs in a model that contains tension-only or compression-only springs.
You may want to change the system of input units to convenient values for your spring constants before creating a spring support type.
Note: Multilinear springs can only be used with a select set of analysis
types. Each load case should be separated by a Change command as well. See
TR.27.4 Multilinear Spring Support Specification
for details.