Section Definition

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)

$$F={\displaystyle \sum f_i}$$

(2)

$$M={\displaystyle \sum m_i}+{\displaystyle \sum O{N}_i}\times f_i$$