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!SPRING_A

Definition of axial spring.

A spring acting along the axis connecting the two nodes of a 2-node connector element (element type 511) is defined. The direction of the spring follows the deformation of the model. To define a spring that connects specific degrees of freedom, use !SPRING_D.

Definition in the Mesh Data

!SPRING_A gives the spring constant as a material property; it does not create a spring by itself. The following two definitions are required in the mesh data (msh).

  • An element of type 511 whose connectivity is the two nodes connected by the spring (see !ELEMENT)
  • A section with TYPE=INTERFACE for that element group (see !SECTION). Give as MATERIAL the name of the material whose spring constant is defined by this keyword

Parameter

None

** 2nd Line **

Define axial spring coefficient.

    (2nd line) SPRING_COEFF
Parameter Name Attributions Contents
SPRING_COEFF R Spring constant

Example of Use

When defining an axial spring (spring constant 1000) connecting node 1 and node 2

msh

!ELEMENT, TYPE=511, EGRP=ESPRING
1, 1, 2
!SECTION, TYPE=INTERFACE, EGRP=ESPRING, MATERIAL=SPRING1
1.0

cnt

!MATERIAL, NAME=SPRING1
!SPRING_A
1000

Note:

  • An axial spring has stiffness only in the axial component. The degrees of freedom normal to the spring axis must be constrained or supported by other elements.
  • When the two nodes have identical coordinates (the spring length is zero), the axial direction is undefined and the spring constant is given equally in the three directions.
  • A material with a spring constant is treated as a material dedicated to connector elements. The same material name cannot be shared with solid elements by also giving elastic properties to it.
  • !SPRING_A is a spring of a connector element connecting two nodes. It differs in purpose from !SPRING, which is a boundary condition that elastically supports a node against the ground.