Section Definition

A section is a cut in the structure where forces and moments will be computed and stored in output files.

It is defined by:
  • A cutting plane
  • A reference point to compute forces
  • A direction of the section.

Figure 1. Definition of a Section for an Oriented Solid
In Radioss the cutting plane is defined by a group of elements and its orientation by a group of nodes as shown in Figure 2.

Figure 2. Definition of a Section for a Shell Mesh
Then, a point is defined for the center of rotation of the section and a reference frame is attached to this point to compute the internal efforts.

Figure 3. Center of Rotation and its Associated Frame for a Section
The resultant of all forces applied to the elements and its application point are computed by:(1)
F = f i
M = m i + O N i × f i

Figure 4. Resultant of Force and Moment for a Node I with the Rotation Point O