In addition to our technical support (e.g. via chat), you’ll find resources on our website that may help you with your design using Dlubal Software.
Frequently Asked Questions (FAQ)
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It is possible to display or calculate the stresses in RFEM as well as in the add-on module by means of the following smoothing options:
- Constant on elements
- Not continuous
- Continuous within surfaces
- Continuous total
- Continuously by groups or Continuous by groups
To compare the results, the same display type and calculation type must be selected in RFEM and RF-STEEL Surfaces.
In RFEM, it is possible to do this in the Project Navigator Show → Results → Surfaces → Distribution of Internal Forces/Stresses (Figure 02). In RF-STEEL Surfaces, this can be displayed or changed in the Details → 'Options' tab (Figure 03).
AnswerBy using the FE mesh refinement, the program allows you to create a mapped FE mesh. The automatic FE mesh generator can thus be controlled to a certain extent. However, it is not possible to use it for setting the given mesh geometry.
The "Without membrane tension" stiffness type describes the plate and plane stiffness of surfaces.The plate stiffness including the shear stiffness perpendicular to the surface plane is defined linearly elastic and the plate stiffness in the surface plane is defined nonlinearly elastic with the material model according to "Drucker-Prager" depending on the defined thickness and the assigned material.In order to ensure that the surface behavior is "Without tension" in the pane direction, the nonlinear material model reacts with yielding tensile stress fy,t going to almost zero in the elements subjected to tension in combination with a relatively small strain hardening modulus Ep. On the other hand, in the case of compressive forces, the elements remain virtually unaffected linearly elastic due to the relatively high yielded compressive stress fy,c and react with an unrestricted compression transmission.Since the "Without membrane tension" stiffness type basically modifies the pane-related degrees of freedom of the surfaces, it is only applied to the surfaces of the relevant model types 3D, 2D - XZ (uX/uZ/φY) and 2D - XY (uX/uY/φZ).To better describe the partial nonlinearity of this surface stiffness type, it was renamed from "Without tension" to "Without membrane tension" as of the Version RFEM 5.06.1103 on 4.02.2016.The Knowledge Base article "Modeling Approaches for Shear/Hole Bearing Connections by Means of FEa" shows possible application.
Rotated surfaces are often used in RFEM to easily model and calculate geometrical conditions. However, if you use a large number of rotated surfaces in the model, you may experience performance drop. This is due to the definition of the surfaces, because they have to be generated in the background again and again using the boundary conditions if a change occurs in the structural system.
Therefore, it is recommended to replace the rotated surfaces by the surfaces of the 'Quadrangle' type, which significantly reduce the amount of data. Furthermore, the quadrangle surfaces also allow you to apply loads to parts of the surface only.
AnswerYou can use the surface releases, but you need to separate the overlapping part with an own surface. Overlapping surfaces should be avoided in general and can be checked by the "Model Check" (Tools → Model Check → Overlapping Surfaces). Please watch the video file (see link below) to see the approach. Alternatively you can add a "Contact Solid" between the two surfaces.
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Wind Simulation & Wind Load Generation
With the stand-alone program RWIND Simulation, wind flows around simple or complex structures can be simulated by means of a digital wind tunnel.
The generated wind loads acting on these objects can be imported to RFEM or RSTAB.
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