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.

Select one or more nodes assigned with spring support types.
On the Specifications ribbon tab, select the Other Supports > Multi-Linear Spring tool in the Supports group. The Create Support dialog opens to the Multilinear Spring tab.
In the table, type the Spring Stiffness constant which corresponds to a Displacement. These should be in order starting with the minimum displacement (e.g., this may also be the largest negative displacement) to the maximum positive displacement. All spring constants should be zero or positive values.
Click Assign.