RFEM 5

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RFEM 5

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6.1

General description

Nodal loads are forces and moments that act on nodes (see Chapter 4.1).

To apply a nodal load, a node must already be defined.

Figure 6.10 New Nodal Load dialog box
Figure 6.11 Table 3.1 Nodal Loads

The nodal load's number is automatically assigned in the New Nodal Load dialog box and can also be changed there. The numbering's sequence is not important.

On Nodes No.

In this text box, specify the numbers of the nodes on which the load acts. You can also select nodes graphically with .

When you have selected the graphical input by clicking the toolbar button, you have to enter the load data first. After clicking [OK], you can select the relevant nodes one by one in the work window.

Definition Type

It is possible to define nodal loads By components with reference to the axes of the global or user-defined coordinate system or By direction with reference to an object.

Coordinate System

In most cases, forces and moments are related to the global coordinate system as vectors By components. A user-defined coordinate system can also serve as a reference.

Force PX / PY / PZ

For the By components definition type, you have to enter the values of the forces in these text boxes or table columns. If the model type has been restricted to a planar system in the general data, you can only access the relevant boxes.

Moment MX / MY / MZ

These text boxes and table columns manage the values of the moments.

A positive moment acts clockwise about the corresponding positive global or user-defined axis. Input is facilitated by the global axes of coordinates in the RFEM graphic.

Moments can not only be displayed as vectors but also as arcs. To control the display properties (see Chapter 11.1.2), use the menu option

    • Options → Display Properties → Edit.

The Display Properties dialog box opens where you set the Category Loads → Nodal Loads → Nodal Moments. Then the Arc display option is available for selection on the right.

Figure 6.12 Section of Display Properties dialog box: Nodal moments with Arc display option

It is also possible to import nodal loads from Excel spreadsheets (see Chapter 12.5.2).

Direction Type

For the definition type By direction, it is possible to describe the load direction independent of a coordinate system. For this, there are different definition options available in the list.

When you select an option, the Edit Direction dialog box opens where you can enter additional parameters.

Figure 6.13 Edit Direction dialog box
Force P

For the definition type By direction, you have to enter the values of the forces in these text boxes or table columns.

Moment M

These text boxes and table columns manage the values of the moments.

Converting nodal loads into surface loads

Nodal loads often result in singularities because the load is concentrated when introduced in a single FE node. To reduce this effect, select the Convert Nodal/Line Load to Surface Load option in the Tools menu. You can also use the shortcut menu of a nodal load shown on the left to access the dialog box for converting nodal loads. As usual, right-click the object to open the shortcut menu.

A dialog box opens (see Figure 6.14) where you can define the parameters for distributing the load. After clicking [OK], the corresponding free rectangular or circular load is created.

Figure 6.14 Convert Nodal Load to Surface Load dialog box