Revision of Ver.7.4.1

Surface Spring Supports

Enter spring stiffness per unit supporting area of planar or solid elements to create elastic spring supports. Elastic Link elements may be created simultaneously. This function is mainly used to define a number of elastic supports on surfaces represented by the modulus of spring. For example, if the user wishes to define elastic supports for subgrades of foundations or underground structures, subgrade springs will be automatically entered at each node represented by concentrated stiffness. This function enable the user to specify the surface or line stiffness without having to worry about the discretization (sizes) of elements, which is automatically taken care of by the program.  

From the Main Menu select Model > Boundaries > Surface Spring Supports.

Select Geometry > Boundaries > Surface Spring Supports in the Menu tab of the Tree Menu.

Click to the right of Surface Spring Supports: Display the Surface Spring Supports Table

Note
The data entered in Surface Spring Supports are converted into Point Spring Supports or Elastic Link data and saved as such.

Revision of Ver.7.4.1

 Boundary Group Name

Select a Boundary Group in which the specified boundary condition is included. Select "Default" if Group assignment is unnecessary. Click to the right to prompt the "Define Boundary Group" dialog box to add, modify or delete Boundary Groups.

 

Surface Spring

Convert to
Select a type of data to be created using the stiffness per unit area.

Point Spring: Point spring support

Elastic Link: Elastic link element

Element Type
Assign the type of elements for which elastic spring supports or elastic link elements are to be created.

Frame: Create elastic spring supports or elastic link elements on the nodes of beam elements.

Width: Width of beam elements to calculate the support stiffness per unit length.

Planar: Create elastic spring supports or elastic link elements on the nodes of planar elements.

Solid (Face): Create elastic spring supports or elastic link elements on a face of solid elements.

Solid (Node): Create elastic spring supports or elastic link elements on the nodes of solid elements

Note
If the element type is selected as solid, a face of the elements must be specified.

 

When Point Spring is selected

 

• Spring Type : Linear

Modulus of Subgrade Reaction: Subgrade stiffness

Kx: Stiffness per unit area in the node's local x- direction (GCS X-direction)

Ky: Stiffness per unit area in the node's local y- direction (GCS Y-direction)

Kz: Stiffness per unit area in the node's local z- direction (GCS Z-direction)

 

 

• Spring Type : Compression / Tension

Direction: Direction of the Point Spring

Normal(+): Normal (+ dir) to the surface (average normal direction of surfaces connected to the node defined with Point Spring)

Normal(-): Normal (- dir) to the surface (average normal direction of surfaces connected to the node defined with Point Spring)

Note

The normal direction of planar elements is defined by the right hand rule based on the node entry sequence. For solid elements, the normal direction (+) is oriented away from the surfaces of the elements.

UCS-x(+): UCS +x-direction (GCS +X-direction)

UCS-x(-): UCS -x-direction (GCS -X-direction)

UCS-y(+): UCS +y-direction (GCS +Y-direction)

UCS-y(-): UCS -y-direction (GCS -Y-direction)

UCS-z(+): UCS +z-direction (GCS +Z-direction)

UCS-z(-): UCS -z-direction (GCS -Z-direction)

Modulus of Subgrade Reaction: Subgrade stiffness

 

When Elastic Link is selected

Direction: Direction of the elastic link

Normal(+): Normal direction of the surface (average normal direction of surfaces connected to the node defined with Elastic Link)

Normal(-): Normal direction of the surface (average normal direction of surfaces connected to the node defined with Elastic Link)

Note
The normal direction of planar elements is defined by the right hand rule based on the node entry sequence. For solid elements, the normal direction (+) is oriented away from the surfaces of the elements.

UCS-x(+): UCS +x-direction (GCS +X-direction)

UCS-x(-): UCS -x-direction (GCS -X-direction)

UCS-y(+): UCS +y-direction (GCS +Y-direction)

UCS-y(-): UCS -y-direction (GCS -Y-direction)

UCS-z(+): UCS +z-direction (GCS +Z-direction)

UCS-z(-): UCS -z-direction (GCS -Z-direction)

Modulus of Subgrade Reaction: Subgrade stiffness

Length of Elastic Link: Length of elastic link element. The length dose not affect the analysis. It is simply required to define a vector internally in the solver.

Tens. Only, Comp.-Only: Check in an option to assign elastic link with tension-only or compression-only elements