Openings are used to create cutouts into surfaces. In areas where openings are placed, no finite elements are generated nor are surface loads applied.
Openings can be set graphically into surfaces. RFEM creates a polygonal chain for various types of openings and integrates it into the surface.
Enter the lines that enclose the opening in this text box. The lines must be defined as a polygonal chain. Openings on the edge of a surface are allowed as well.
When you use the graphical selection, click the opening's boundary lines one after the other in the graphic. Once a sufficient number of boundary lines has been defined, RFEM automatically recognizes the opening.
Use the Select Boundary Lines button in the openings menu list to graphically select previously defined lines. The lines must form a closed continuous line.
Openings can be placed directly into a surface that lies in the work plane by using one of the buttons shown on the left. The definition types for openings are, in a somewhat reduced form, based on the line types described in Chapter 4.2 (e.g. circle, ellipse). Once the contour lines have been determined, the opening is created. With this input option, it is not necessary to create lines for the opening in advance.
For plane surfaces, the automatic integration is active by default. For curved surfaces, you have to integrate the opening manually. In the Edit Surface dialog box, go to the Integrated tab and enter the number of the opening into the text box (see Figure 4.74).
This table column shows the area of the opening.