How to display the primary load-bearing direction graphically in RF-LAMINATE?


Displaying the primary load-bearing direction in the RF-LAMINATE add-on module
While entering data in the RF-LAMINATE add-on module, there is an option to control the orthotropic direction of each individual layer graphically. To do this, simply place the cursor in the desired row of the corresponding position. Then, a coordinate system is displayed in the surface in the RFEM model (see Figure 01). This is to be interpreted as follows:

red axis = x-axis = β-value of the corresponding layer

Generally, the outer layers specify the main load-bearing direction, which is why it is sufficient to consider only the first layer. The red axis specifies the primary load-bearing direction (see Figure 01).

Displaying the primary load-bearing direction in RFEM
However, the primary load-bearing direction can also be interpreted directly in RFEM. The local axis systems of the surfaces can be displayed in detail (see Figure 02). The orthotropic direction β refers to the local x-axis of the surface. For the example shown in Figure 03, it has a consequence that the primary load-bearing direction for the left surface runs from one support to another and the secondary surface direction to the right surface. If you want to change the supporting direction for the right surface, it is possible to either rotate the local surface axis system (see Figure 04) or create a new structure and rotate the orthotropic direction β by 90° (see Figure 05).

If the primary load-bearing direction is not clearly evident, it is worth taking a look at the stiffness matrix of the surface (see Figure 06). There, it is possible to find the 'decisive' load-bearing direction, e.g. by means of the bending stiffness. The element D11 refers to the local x-axis of the surface and the element D22 refers to the local axis y of the surface.


Primary load-bearing direction Secondary load-bearing direction Orientation Axis system


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RFEM Main Program
RFEM 5.xx

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Structural engineering software for finite element analysis (FEA) of planar and spatial structural systems consisting of plates, walls, shells, members (beams), solids and contact elements

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Deflection analysis and stress design of laminate and sandwich surfaces

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