FEA Boundary Conditions

Nodal and element face boundary conditions in FEA analyses are applied to nodes or elements by using the commands on this page.

Scripted Input Files

In scripted input files, FEA boundary conditions are applied with a series of FixLine commands, which is available in two versions. The first one selects a line through the mesh. All nodes close to that line can be assigned load or dislacement conditions or rotated for skewed boundary conditions. The second one selects a previously defined path. All nodes along that path can be assigned nodal load or displacement conditions, rotated for skewed boundary conditions. All or element faces can be assigned stresses. The formats of the two forms are:

FixLine #1,#2,#3,#4,<#5>

 Displacement #1,<#2>
   .
 Load #1,#2
   .
 Rotate #1,#2
   .
 Select

EndFixLIne and

FixLine #6

 Displacement #1,<#2>
   .
 Load #1,#2
   .
 Rotate #1,#2
   .
 Stress #1,#2,<#3>,<#4>
   .
 Select

EndFixLIne where

(#1, #2) and (#3, #4) define (x, y) coordinates (in mm) for the points at the beginning and end of the line (or (R, Z) coordinates in axisymmetric calculations).

1. 5 is optional tolerance (in mm).
2. 6 is the id of a previously defined path.

Within FixLine blocks, there can be Displacement commands and Load commands to set displacements or loads in the x and/or y direction, a Rotate command to rotate the nodes for skewed boundary conditions, Stress commands to apply normal and/or tangential stresses on element faces, or a Select command to select nodes for conditional output of results. All nodes within a distance specified by the tolerance (#5) of the selected line or along the defined path (#6) will be assigned each specified nodal boundary condition or rotated. Stress boundary conditions can only be applied along paths in the second version of the command.