Skip to content

!SPRING¶

Definition of spring boundary conditions

This boundary condition elastically supports the specified degree of freedom of a specified node against the ground using a spring. No element needs to be defined in the mesh data. To connect two nodes with a spring, use the connector-element springs !SPRING_A / !SPRING_D, which serve a different purpose.

Parameters¶

GRPID = Group ID
AMP = Amplitude function name (specified with !AMPLITUDE)
INCREMENTAL = NO (resists accumulated displacement; default) / YES (resists only displacement increments)

** Second and subsequent lines **

(2nd line) NODE_ID, DOF_id, Value

Variable	Type	Description
NODE_ID	I/C	Node number or node group name
DOF_id	I	Constrained degree of freedom
Value	R	Spring constant

Example¶

!SPRING, GRPID=1
  1, 1, 0.5

When specifying INCREMENTAL=YES for node 1 and AMP=AMP1 for node 2

!SPRING, GRPID=1, INCREMENTAL=YES
  1, 1, 0.5
!SPRING, GRPID=1, AMP=AMP1
  2, 1, 0.5

Notes¶

!SPRING can be used in static analysis and implicit dynamic analysis.
GRPID is referenced from !STEP through its LOAD line and is used to activate spring support for each step.
For the behavior of spring supports with INCREMENTAL and AMP, see Functions Reference: Boundary Conditions and Loads.

See Also¶