Frequently Asked Questions (FAQ)

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Knowledge Base

Knowledge Base

In the Knowledge Base page, you’ll find technical articles and tips & tricks that may help you with your design using Dlubal Software.


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  • Answer

    RSTAB is a 3D structural frame analysis program where the design of 2D and 3D frameworks is possible. The efficient RSTAB solver allows for linear and nonlinear calculations of internal forces, deformations, and support reactions.

    With RFEM, you extend the member design by plates, shells and solids according to the Finite Element Method. These elements can be combined arbitrarily in a structure. RFEM contains almost all functions from RSTAB; that is why also pure frameworks can be designed with it.

    The user interface and the handling of RSTAB and RFEM are almost identical, but RFEM offers more functions due to the greater scope of the program. The import of structure and load date from RSTAB to RFEM and vice versa is possible as long as the objects are supported by both programs.

    Various add-on modules are available for structural design in RSTAB and RFEM considering both material and standard-specific requirements. Thanks to the modular software concept, it is possible to put together a program package which is adapted to the individual needs. It is possible to upgrade the program at any time.
  • Answer

    If a rolled cross-section with the desired dimensions is not available in the cross-section library, it can be created manually. To do so, select the cross-section you wish to change and click the "Parametric Input" button. A dialog box opens where you can enter the desired data (see Figure 1).
  • Answer

    Yes, support forces of single surfaces can be displayed in the table "4.21 Surfaces - Contact Stresses" available in the RFEM table window. This table can be opened by right-clicking one of the tabs of the "4.xx - Results" table (see Figure 1). In addition to the contact stresses, you can also see the corresponding support forces (see Figure 2).
  • Answer

    You find this setting in the "General Data" of the model.
    You can distinguish between the model types "3D", "2D - XY", "2D - XZ" and "2D - XY".

    If you want to enter a floor as a 2D model, and the axial forces within the slab should not be taken into account, set the model type to "2D - XY". If you want to enter a wall, set "2D - XZ".

    Find more information in the RFEM manual, chapter 12.2.1 General - Type of Model.
  • Answer

    First, select the National Annex "DIN" in the "1.1 General Data" window. Then, open the [Details...]. A dialog box opens where you can find the design for limiting the gaping joint which is described as "Highly eccentric loading in the core". See Figure 01.
  • The address and/or company name was changed in the authorization file, but this is not applied in the print header



    The title block of the printout report is created using the authorization file, which was used in the initial installation of our programs. 
    A subsequent change in the authorization file does not necessarily change all report headers immediately.

    For the changed title block to be created as default in the authorization file, the "old" one has to be removed first.
    To do so, please delete the file "DlubalProtocolConfigNew.cfg" in the following (default) directory:
    C:\ProgramData\Dlubal\Global\General Data

    While deleting the file, our applications must be closed!
  • Answer

    Yes, this is done by creating a user-defined cross-section in the cross-section library.
  • Answer

    RFEM provides two ways to divide surfaces:

    1)  Split Surface

    The requirements to split a surface evenly are that it has four sides and is convex; in other words, none of the four internal angles may be greater than 180°.
    This function is accessed by right-clicking the surface and selecting "Split Surface". In the corresponding "Split Surface" dialog box, the number of divisions in each direction and the individual relative distances are entered (see Figure 1).

    2)  Divide Surface

    If any lines are drawn within the surface plane, they may be used to divide the surface (see Figure 2). First you have to check, whether the division lines are integrated in the surface. This is normally the case due to the automatic object detection (see Figure 3). Afterwards, right-click on the surface and select "Divide Surface" to use the desired function (see Figure 4).
  • Answer

    To take into account external concentrated loads that act eccentrically on a member, it is possible to model a connection via a rigid member. The rigid member is connected perpendicularly to the corresponding member, and the length of the rigid member corresponds to the value of the eccentricity.
    Alternatively, the corresponding torsional moment, which is a result of the eccentric load introduction, could be entered as external loading. This way, it would not be necessary to define a rigid member and the corresponding eccentricity would still have been taken into account.
  • Answer

    To use SHAPE-MASSIVE cross-sections for tapered members, two conditions must be met.
    1st In the General Data of the SHAPE-MASSIVE structure, the option "Stresses in stress points" must be deactivated. See Figure 01.
    2nd The nodes (corner points) of the cross-sections used for the taper must be arranged the same way in both cross-sections. See Figure 02.

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