Element: Create Surface Spring

Function

Creates Point Spring elements or Elastic links by entering Spring Stiffness per unit area.

Call

 Model > Element > Create Surface Spring

<Create Surface Spring: Point Spring>

<Create Surface Spring: Elastic Link>

Object

Assign a Surface Spring type.
 

Frame

Create Point Spring or Elastic Link at nodes of 1D element. Element Width must be entered to calculate Spring Stiffness per unit length.
Planar

Create Point String or Elastic Link at nodes of 2D element.
Solid-Face

Select faces of 3D element, and create Point String or Elastic Link at nodes of the selected faces.

Element Edge

 Select Element Edge where Surface Spring will be assigned.
 

Convert to

Select a Surface Spring type.
 

Point Spring

Create a Point Spring.
 

Modulus of Subgrade Reaction

Enter the Modulus of Subgrade Reaction.

Kx

Enter Spring Stiffness per unit area in nodal local x-direction.

Ky

Enter Spring Stiffness per unit area in nodal local y-direction.

Kz

Enter Spring Stiffness per unit area in nodal local y-direction.

The following formulas can be used to obtain the Modulus of Subgrade reaction.  Please refer to country design code for further explanation.

where,

Damping Constant/Area

Enter the Damping Constant per unit area.

Cx

Enter Damping Constant per unit area in nodal local x-direction.

Cy

Enter Damping Constant per unit area in nodal local y-direction.

Cz

Enter Damping Constant per unit area in nodal local z-direction.

The following formulas can be used to obtain the Damping constants.  

where,

lambda: Volumetric Elastic Modulus

G: Shear Elastic Modulus

v: Poisson's Ratio

A: Cross-sectional Area

Elastic Link

 Create a Elastic Spring.

BC Set

Select a Boundary Condition Set in which the Surface Spring boundary condition is included. Click to the right to add, modify, or delete Boundary Set.

Direction

Select direction of Elastic Link element. It can be selected between the positive and negative normal direction of surface.

Modulus of Subgrade Reaction

Enter the Modulus of Subgrade Reaction.

Length of Elastic Link

Enter the length of Elastic Link.

Tens.-Only, Comp.-Only

Creates tension only or compression only elastic link.

Max. Number of Properties

Enter the maximum number of properties which can be assigned to the Surface Spring function.
 

MergeNodes

Mesh Set

Notes

Although Surface Spring is registered and managed as Mesh Set, it will be treated as Boundary Condition Set in analysis. Therefore, both BC Set and Mesh Set must be defined.